Semi-final pool the rest (organized) Flashcards by Gil Eizenberg

Which amino acid is an activator of N-acetyl-glutamate synthase?

Select one:

a. glutamine
b. lysine
c. arginine
d. aspartate
e. asparagine

The correct answer is:

c. arginine

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In what form is ammonia transported from muscle to the liver?

Select one:

a. asparagine
b. arginine
c. leucine
d. glutamine
e. valine

The correct answer is:

b. glutamine

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Which hepatocytes express the highest activity of the ornithine cycle enzymes?

Select one:

a. periportal
b. pericentral
c. perivenous
d. centrolobular

The correct answer is:

a. periportal

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Which amino acid contributes to the increase in the activity of sirtuins?

Select one:

a. tryptophan
b. phenylalanine
c. tyrosine
d. valine
e. glutamine

The correct answer is:

a. tryptophan

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What is the effect of acidosis on the activity of glutamine synthesis in the liver?

Select one:

a. increase in the periportal hepatocytes
b. increase in the pericentral hepatocytes
c. decrease in the perivenous hepatocytes
d. decrease in all regions of the lobules

answer:

b. increase in the pericentral hepatocytes

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Which amino acid does NOT contribute to the formation of pyruvate in the course of its degradation?

Select one:

a. Alanine
b. Glutamine
c. Tyrosine
d. Leucine
e. spartateAAspartate

The correct answer is:

d. Leucine

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Which amino acid can NOT provide any C-atom for the synthesis of glucose in humans?

Select one:

a. Glutamate
b. Isoleucine
c. Leucine
d. Phenylalanine
e. Tryptophan

The correct answer is:

c. Leucine

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Which pair of amino acids are released at the highest concentration from skeletal muscle in the fasting state?

Select one:

a. Glutamate, aspartate
b. Glutamine, asparagine
c. Alanine, glutamine
d. Alanine, leucine
e. Valine, leucine

The correct answer is:

c. Alanine, glutamine

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What happens in the course of glutaminolysis?

Select one:

a. Glutamine is converted to aspartate
b. Glutamine is converted to asparagine
c. Glutamine is completely oxidized to CO2 and water
d. Glutamine is converted to glucose

The correct answer is:

a. Glutamine is converted to aspartate

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Which amino acid is the most common source of the 1C-groups transferred by tetrahydrofolate?

Select one:

a. Alanine
b. Serine
c. Threonine
d. Isoleucine
e. Methionine

The correct answer is:

b. Serine

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Deficiency of which vitamin would cause enhanced excretion of methylmalonate in the urine?

Select one:

a. B1
b. B2
c. biotin
d. B12
e. D

The correct answer is:

d. B12

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Which amino acids should be enriched in the diet of a patient with phenylketonuria?

Select one:

a. Phe, Gln
b. Arg, Lys
c. Trp, Tyr
d. Asp, Glu
e. Ala, Glu

The correct answer is:

c. Trp, Tyr

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Which interconversion includes glutamic semialdehyde as an intermediate?

Select one:

a. Arginine to Proline
b. Glutamate to Glutamine
c. Glutamate to α-ketoglutarate
d. Methionine to Threonine

The correct answer is:

a. Arginine to Proline

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Which vitamin is a co-factor in the synthesis of hydroxyproline?

Select one:

a. B1
b. B2
c. B6
d. B12
e. C

The correct answer is:

e. C

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What is the role of Se in the function of the thyroid gland?

Select one:

a. Se participates in the structure of thyroxine
b. Se participates in the structure of thyroglobulin
c. Se participate in the structure of deiodinase
d. Se forms a complex with iodine to activate it for thyroxine synthesis

The correct answer is:

c. Se participate in the structure of deiodinase

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How is the nitrogen balance changed, if the food is depleted of Leu, but all other amino acids are doubled?

Select one:

a. no change
b. negative N-balance
c. positive N-balance
d. positive N-balance only in children
e. positive N-balance only in adults

The correct answer is:

b. negative N-balance

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How is the nitrogen balance changed, if the food is depleted of Glu, but all other amino acids are doubled?

Select one:

a. no change
b. negative N-balance
c. positive N-balance
d. negative only in children
e. positive N-balance only in adults

The correct answer is:

a. no change

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Dietary supplementation with which amino acid could counteract the sleep-promoting effect of serotonin?

Select one:

a. Glu
b. Trp
c. Leu
d. Lys
e. Arg

The correct answer is:

c. Leu

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Which one is a metalloprotease?

Select one:

a. pepsin
b. trypsin
c. elastase
d. carboxypeptidase
e. chymotrypsin

The correct answer is:

d. carboxypeptidase

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Which zymogen does not need another protease for its activation?

Select one:

a. trypsinogen
b. pepsinogen
c. chymotrypsinogen
d. proelastase

The correct answer is:

b. pepsinogen

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Which amino acid is present in the active site of the proteasome proteases?

Select one:

a. Aspartate
b. Tyrosine
c. Lysine
d. Threonine
e. Trpyptophan

The correct answer is:

d. Threonine

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Which metal ion is present in the active site of the matrix metalloproteases?

Select one:

a. Zn2+
b. Fe2+
c. Fe3+
d. Cu2+
e. Ca2+

The correct answer is:

a. Zn2+

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Which amino acid acts as a signal to suppress autophagy?

Select one:

a. Glycine
b. Leucine
c. Glutamate
d. Glutamine
e. Arginine

The correct answer is:

b. Leucine

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Which compound is the first N-free intermediate released in the indirect deamination of aspartate?

Select one:

a. pyruvate
b. oxaloacetate
c. fumarate
d. α-ketoglutarate
e. methylmalonate

The correct answer is:

c. fumarate

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Which protein kinase is activated to transmit the anabolic signal of insulin? Select one: a. PKA b. AMPK c. PKC d. mTOR

The correct answer is: d. mTOR

Where is hepcidin produced? Select one: a. liver b. spleen c. intestine d. adrenal gland e. pancreas

The correct answer is: a. liver

What is the normal degree of transferrin saturation with iron? Select one: a. 10 % b. 30 % c. 60 % d. 80 % e. 100-120 %

The correct answer is: b. 30 %

Which intermediate is elevated in blood in lead poisoning? Select one: a. δ-aminolevulinate b. protoporphyrin c. haem d. bilirubin e. biliverdin

The correct answer is: a. δ-aminolevulinate

Which factor regulates the activity of aminolevulinate synthase 1 (ALAS1)? Select one: a. ferroportin b. transferrin receptor 2 c. haem d. iron response element binding protein 1 e. ferritin

The correct answer is: c. haem (\*heme)

Which factor regulates the activity of aminolevulinate synthase 2 (ALAS2)? Select one: a. protoporphyrin b. hemoglobin c. haem d. iron response element binding protein 1 e. ferroportin

The correct answer is: d. iron response element binding protein 1

Which compound is a substrate of haem oxygenase? Select one: a. O2 b. CO c. CO2 d. HCO3-

The correct answer is: a. O2

Which compound is a product of haem oxygenase? Select one: a. CO b. O2 c. CO2 d. HCO3- e. NADPH

The correct answer is: a. CO

Why is blue light used to treat neonatal icterus? Select one: a. blue light promotes the conjugation of bilirubin b. blue light activates the haem oxygenase in the skin c. blue light generates lipid-soluble photoisomers of bilirubin d. blue light generates photoisomers of bilirubin with higher water solubility

The correct answer is: d. blue light generates photoisomers of bilirubin with higher water solubility

In what form do the dietary purine bases enter the blood circulation? Select one: a. nucleotide b. nucleoside c. free base d. uric acid

answer: d. The correct answer is: uric acid

Which enzyme is needed for the salvage of purine bases? Select one: a. phosphoribosyl-pyrophosphate synthetase b. xanthine oxidase c. xanthine dehydrogenase d. AMP deaminase

The correct answer is: a. phosphoribosyl-pyrophosphate synthetase

Which two amino acids contribute with 2 N-atoms each to the de novo synthesis of one adenine? Select one: a. Asparagine, Glutamine b. Aspartate, Glutamine c. Asparagine, Glutamate d. Aspartate, Glutamate

The correct answer is: b. Aspartate, Glutamine

Which amino acid contributes with both C- and N-atoms to the de novo synthesis of adenine? Select one: a. Glycine b. Glutamine c. Aspartate d. Tryptophan

The correct answer is: a. Glycine

The degradation of which nucleotide generates propionyl-CoA? Select one: a. AMP b. GMP c. UMP d. TMP

The correct answer is: d.TMP

Which amino acid contributes with 4 atoms to the de novo synthesis of one pyrimidine ring? Select one: a. Glycine b. Proline c. Aspartate d. Proline

The correct answer is: c. Aspartate

Which compound is a substrate of the ribonucleotide reductase? Select one: a. AMP b. ADP c. ATP d. phosphoribosyl-pyrophosphate

The correct answer is: b. ADP

Select all valid statements! Select one or more: a. In the course of the urea cycle fumarate is produced b. Enzymes of the urea cycle participate in the de novo synthesis of arginine c. The amide group of glutamine serves as nitrogen source for the N-acetylglutamate-activated carbamoylphosphate synthetase d. Ornithine can be synthesized from glutamate

The correct answers are: a. In the course of the urea cycle fumarate is produced. b. Enzymes of the urea cycle participate in the de novo synthesis of arginine d. Ornithine can be synthesized from glutamate

Select all valid statements! Select one or more: a. Citrullin is an intermediate of the urea cycle b. Citrullin is a precursor of the de novo arginine biosynthesis c. Urea may be produced by the kidney d. Arginine may be produced by the kidney

The correct answers are: a. Citrullin is an intermediate of the urea cycle b. Citrullin is a precursor of the de novo arginine biosynthesis d. Arginine may be produced by the kidney

Select the false statement! Select one: a. Urea can be produced by the kidney b. The nitrogen atoms present in urea are derived from free ammonium ion and from aspartate c. The de novo synthesis of arginine requires ornithine synthesis d. Ornithine is synthesized from glutamate e. Arginine may be produced in the kidney

The correct answer is: a. Urea can be produced by the kidney

A part of the carbon skeleton of which amino acids may enter the citric acid cycle in the form of succinyl-CoA? Select one or more: a. Isoleucine b. Leucine c. Tyrosine d. Proline e. Valine

The correct answers are: a. Isoleucine e. Valine

A part of the carbon skeleton of which amino acids may enter the citric acid cycle in the form of a-ketoglutarate? Select one or more: a. Proline b. Glutamine c. Arginine d. Cysteine e. Phenylalanine

The correct answers are: a. Proline b. Glutamine c. Arginine

A part of the carbon skeleton of which amino acids may enter the citric acid cycle? Select one or more: a. Leucine b. Asparagine c. Phenylalanine d. Tyrosine

The correct answers are: a. Asparagine b. Phenylalanine c. Tyrosine

Which of the following answer(s) complete(s) the sentence correctly? Glutamate is reduced to glutamic semialdehyde in the course of the formation of........ Select one or more: a. Ornithine. b. Proline. c. Glutamine. d. Glutathione. e. g-aminobutyrate.

The correct answers are: a. Ornithine b. Proline.

Select all valid statements! Select one or more: a. Formation of tyrosine is an essential step in the physiological degradation of phenylalanine b. Degradation of phenylalanine starts with removal of the amino group by phenylalanine a-ketoglutarate transaminase c. The carbon skeleton of phenylalanine yields acetoacetate

The correct answers are: a. Formation of tyrosine is an essential step in the physiological degradation of phenylalanine c. The carbon skeleton of phenylalanine yields acetoacetate

Select all valid statements! Select one or more: a. Formation of tyrosine is an essential step in the physiological degradation of phenylalanine b. Phenylalanine may loose its amino group by a phenylalanine a-ketoglutarate transaminase under pathological conditions c. Carbon skeleton of phenylalanine yields acetoacetate

The correct answers are: a. Formation of tyrosine is an essential step in the physiological degradation of phenylalanine b. Phenylalanine may loose its amino group by a phenylalanine a-ketoglutarate transaminase under pathological conditions c. Carbon skeleton of phenylalanine yields acetoacetate

Select all valid statements! Select one or more: a. Folic acid should be reduced in order to serve as a one carbon carrier b. S-adenosylmethionine is a methyl-group donor c. Regeneration of S-adenosylmethionine from S-adenosylhomocystein requires B12 vitamin d. One carbon units carried by the derivative of folic acid are derived from S-adenosylmethionine

The correct answers are: a. Folic acid should be reduced in order to serve as a one carbon carrier b. S-adenosylmethionine is a methyl-group donor c. Regeneration of S-adenosylmethionine from S-adenosylhomocystein requires B12 vitamin

Select all valid statements! Select one or more: a. One carbon units carried by tetrahydrofolic acid may be derived from serine, glycine, tryptophan or histidine b. All one carbon units bound by tetrahydrofolic acid can be transformed into each other c. The methyl group carried by tetrahydrofolic acid is derived from methionine

The correct answer is: a. One carbon units carried by tetrahydrofolic acid may be derived from serine, glycine, tryptophan or histidine

Which of the following amino acids are nutritionally essential for the human organism? Select one or more: a. Proline b. Valine c. Phenylalanine d. Methionine e. Cysteine

The correct answers are: b. Valine c. Phenylalanine d. Methionine

Which of the following amino acids are nutritionally non-essential for the human organism? Select one or more: a. Proline b. Valine c. Tyrosine d. Methionine e. Cysteine

The correct answers are: a. Proline c. Tyrosine e. Cysteine

Which of the following amino acids are nutritionally essential for the human organism? Select one or more: a. Isoleucine b. Serine c. Cysteine d. Phenylalanine e. Tryptophan

The correct answers are: a. Isoleucine d. Phenylalanine e. Tryptophan

Select those enzymes which can catalyse directly the release of ammonia! Select one or more: a. Glutaminase b. Glutamate dehydrogenase c. Isoleucine-a-ketoglutarate aminotransferase d. Arginase e. Mitochondrial carbamoylphosphate synthetase

The correct answers are: a. Glutaminase b. Glutamate dehydrogenase

Select those enzymes which can incorporate free ammonia (from ammonium ion) into organic compounds! Select one or more: a. Glutamine synthetase b. Glutamate dehydrogenase c. Mitochondrial carbamoylphosphate synthetase d. Argininosuccinate lyase e. Asparagine synthetase

The correct answers are: a. Glutamine synthetase b. Glutamate dehydrogenase c. Mitochondrial carbamoylphosphate synthetase

Select the false statement! Select one: a. Aspartate is a nitrogen donor in the course of urea formation b. One of the nitrogen atoms of urea is derived from free ammonia c. The amide group of glutamine is removed by glutamate dehydrogenase d. The amino group of alanine may be released as free ammonia in a series of two consecutive reactions e. The transaminase reactions require pyridoxal phosphate

The correct answer is: c. The amide group of glutamine is removed by glutamate dehydrogenase

Which of the following reactions, enzymes or compounds participate in the urea cycle? Select one or more: a. synthesis of carbamoyl phosphate b. aspartate c. formation of argininosuccinate d. ornithine e. arginase

The correct answers are: a. synthesis of carbamoyl phosphate b. aspartate c. formation of argininosuccinate d. ornithine e. arginase

Phenylketonuria can be a consequence of: Select one or more: a. dihydrobiopterin reductase deficiency b. vitamin B6 deficiency c. phenylalanine hydroxylase deficiency d. defective synthesis of biopterin e. vitamin C deficiency

The correct answers are: a. dihydrobiopterin reductase deficiency c. phenylalanine hydroxylase deficiency d. defective synthesis of biopterin

Which of the urea cycle enzymes are not localized in the cytosol? Select one or more: a. carbamoyl phosphate synthetase I b. ornithine transcarbamoylase c. argininosuccinate lyase d. argininosuccinate synthetase e. arginase

The correct answers are: a. carbamoyl phosphate synthetase I b. ornithine transcarbamoylase

What is the fate of the exocytosed glutamic acid localized in the synaptic cleft? Select one or more: a. Glutamate can enter into the postsynaptic neuron by ionotropic receptors b. Glutamate dehydrogenase splits the molecule in the synaptic cleft, the formed alfa-ketoglutarate is taken up by the postsynaptic neuron c. Most of glutamate is taken up by astrocytes at the expense of Na+ gradient. d. Glutamate is transformed into glutamine in astrocytes e. Released glutamate will be recycled to the neurons in the form of glutamine

The correct answers are: c. Most of glutamate is taken up by astrocytes at the expense of Na+ gradient. d. Glutamate is transformed into glutamine in astrocytes e. Released glutamate will be recycled to the neurons in the form of glutamine

Which of the following statements is/are true for the digestive enzymes? Select one or more: a. The carboxypeptidase is a carboxyl protease b. Elastase and pepsin are thiolproteases c. No Zn2+ protease can be found in the gastrointestinal tract d. Both trypsin and chymotrypsin are serine proteases.

The correct answer is: d. Both trypsin and chymotrypsin are serine proteases.

Which of the following agents and enzymes are required for the synthesis of cystein? Select one or more: a. methionine b. adenosylhomocysteinase c. serine d. cystathionine synthase e. cystathionase

The correct answers are: a. methionine b. adenosylhomocysteinase c. serine d. cystathionine synthase e. cystathionase

Which of the following statements are valid for transamination? Select one or more: a. It is a reversible reaction b. The coenzyme of transaminases is a noncovalently bound cobalamin c. In the first step of catalysis ketoacids are attached to the lysine residue of the enzyme forming a Schiff base d. The Schiff base linkage is in tautomeric equilibrium between an aldimine and a ketimine.

The correct answers are: a. It is a reversible reaction d. The Schiff base linkage is in tautomeric equilibrium between an aldimine and a ketimine.

Tetrahydrofolate has the following one-carbon derivatives: Select one or more: a. methyl H4folate b. methylene H4folate c. methenyl H4folate d. carboxyl H4folate

The correct answers are: a. methyl H4folate b. methylene H4folate c. methenyl H4folate

S Adenosylmethionine (SAM) is the methyl donor in the synthesis of Select one or more: a. carnitine b. epinephrine c. choline d. norepinephrine

The correct answers are: a. carnitine b. epinephrine c. choline

S Adenosylmethionine (SAM) is the methyl donor in the synthesis of Select one or more: a. urea b. methyl-malonyl-CoA c. choline d. epinephrine

The correct answers are: c. choline d. epinephrine

Transamination of the following amino acids results in formation of citric acid cycle intermediates Select one or more: a. lysine b. aspartate c. leucine d. glutamate

The correct answers are: b. aspartate d. glutamate

Degradation of the following amino acids results in formation of citric acid cycle intermediates Select one or more: a. valine b. leucine c. isoleucine d. tryptophan

The correct answers are: a. valine c. isoleucine

Which of the following amino acids are ketoplastic? Select one or more: a. serine b. leucine c. cysteine d. lysine

The correct answers are: b. leucine d. lysine

The reaction catalysed by the mitochondrial carbamoyl phosphate synthetase Select one or more: a. uses 2 ATP molecules b. uses glutamine as a substrate c. inhibited by N-acetylglutamate d. activated by N-acetylglutamate

The correct answers are: a. uses 2 ATP molecules d. activated by N-acetylglutamate

Which of the following statements are true for the urea cycle? Select one or more: a. A citric acid cycle intermediate is formed in the cycle b. The enzymes of the cycle are located either in the cytosol or in the mitochondria c. Condensation of citrulline and glutamate requires hydrolysis of ATP d. Synthesis of one urea molecule consumes energy equivalent to three high group transfer potential bonds

The correct answers are: a. A citric acid cycle intermediate is formed in the cycle b. The enzymes of the cycle are located either in the cytosol or in the mitochondria

Synthesis of tyrosine requires Select one or more: a. dietary phenylalanine b. phenylalanine hydroxylase c. tetrahydrobiopterin d. dihydrobiopteridine reductase e. transamination of phenylalanine

The correct answers are: a. dietary phenylalanine b. phenylalanine hydroxylase c. tetrahydrobiopterin d. dihydrobiopteridine reductase

Synthesis of proline involves Select one or more: a. glutamate b. N-methyllysine c. pyrroline-5-carboxylate reductase d. glutamic semialdehyde e. pyrroline-5-carboxylate

The correct answers are: a. glutamate c. pyrroline-5-carboxylate reductase d. glutamic semialdehyde e. pyrroline-5-carboxylate

Tryptophan can be the precursor of the following compounds: Select one or more: a. Lysine b. acetoacetyl-CoA c. nicotinamide d. alanine e. serotonin

The correct answers are: b. acetoacetyl-CoA c. nicotinamide d. alanine e. serotonin

Which of the following enzymes are regulated by N-acetylglutamate? Select one: a. N-acetylglutamate synthase b. Ornithine transcarbamoylase c. Carbamoyl phosphate synthetase I d. Carbamoyl phosphate synthetase II e. Arginase

The correct answer is: c. Carbamoyl phosphate synthetase I

Which of the following parameters are suitable to differentiate the deficiency of carbamoyl phosphate synthetase I and ornithine transcarbamoylase ? Select one: a. Determination of blood pH b. Determination of citrulline level in blood c. Determination of arginine level in plasma d. Determination of orotic acid level in urine e. Determination of ammonia level in blood

The correct answer is: d. Determination of orotic acid level in urine

Patients with deficiency of carbamoyl phosphate synthetase I and ornithine transcarbamoylase are treated with sodium benzoate and sodium phenylacetate. What is the rationale of this treatment? Select one or more: a. Benzoate conjugates with Gly and removes 1 N atom b. Phenylacetate conjugates with hippurate and removes 1 N atom c. Benzoate and phenylacetate activate the enzymes of urea cycle d. Phenylacetate conjugates with glutamine and removes 2 N atoms e. N- containing conjugation products of benzoate and phenylacetate are released in the urine

The correct answers are: b. Benzoate conjugates with Gly and removes 1 N atom d. Phenylacetate conjugates with glutamine and removes 2 N atoms e. N- containing conjugation products of benzoate and phenylacetate are released in the urine

Which of the following intermediates can be converted to serine in a single step reaction? Select one: a. Pyruvate b. Some citric acid cycle intermediates c. Some ornithine cycle intermediates d. Glycine e. Choline

The correct answer is: d. Glycine

Which of the following amino acids are non-essential for an adult human? Select one or more: a. Phe b. Tyr c. Met d. Cys e. Glu

The correct answers are: b. Tyr d. Cys e. Glu

Which of the following proteases is/are involved in the activation of pancreatic proenzymes? Select one or more: a. Carboxypeptidase A b. Enteropeptidase c. Trypsin d. Chymotrypsin e. Elastase

The correct answers are: b. Enteropeptidase c. Trypsin

Which of the following statements are valid for aminotransferases (AT)? The AT needs: Select one or more: a. Efficient amount of Vitamin B6 b. The presence of free aminoacids c. The presence of free ketoacids d. The formation of Schiff base between the amino group of the aminoacid and aldehyde group of pyridoxal phosphate e. The presence of AT in blood circulation

The correct answers are: a. Efficient amount of Vitamin B6 b. The presence of free aminoacids c. The presence of free ketoacids d. The formation of Schiff base between the amino group of the aminoacid and aldehyde group of pyridoxal phosphate

Which of the following statements are valid for the S-adenosylmethionine cycle? Select one or more: a. Met + ATP forms S-adenosylmethionine b. Stable covalent bond exists between one C atom of Met and 5'C atom of adenosine c. S-adenosylmethionine is converted to homocysteine + H2O d. Homocysteine+ N5-Methyl FH4 form Met + FH4 e. Homocysteine methyltranferase uses a vitamin B12 derived cofactor

The correct answers are: a. Met + ATP forms S-adenosylmethionine d. Homocysteine+ N5-Methyl FH4 form Met + FH4 e. Homocysteine methyltranferase uses a vitamin B12 derived cofacto

Which of the following amino acids have their alpha-amino groups removed by dehydratases? Select one or more: a. Histidine b. Tryptophan c. Serine d. Glutamine e. Threonine

The correct answers are: c. Serine e. Threonine

Which of the following amino acids are derived from alpha-ketoglutarate ? Select one or more: a. Glutamate b. Cysteine c. Aspartate d. Proline e. Serine

The correct answers are: a. Glutamate d. Proline

Which of the following statements are valid for N-acetyl-glutamate? Select one or more: a. its concentration depends on the concentration of arginine b. its concentration depends on the concentration of ornithine c. it is an activator of carbamoyl phosphate synthetase I d. it is an inhibitor of argininosuccinate lyase e. it is an activator of ornithine transcarbamoylase

The correct answers are: a. its concentration depends on the concentration of arginine c. it is an activator of carbamoyl phosphate synthetase I

Hyperhomocysteinemia can be the consequence of: Select one or more: a. cystathionine -synthase defficiency b. methylene tetrahydrofolate reductase deficiency c. folate deficiency d. B12 deficiency e. methionine deficiency

The correct answers are: a. cystathionine -synthase defficiency b. methylene tetrahydrofolate reductase deficiency c. folate deficiency d. B12 deficiency

High citrulline levels are characteristic in the following enzyme deficiencies: Select one or more: a. carbamoyl phosphate synthetase b. arginino succinate synthetase c. arginino succinase d. ornithine transcarbamoylase

The correct answers are: b. arginino succinate synthetase c. arginino succinase

Which enzyme is critical in the activation of zymogens for the digestion of proteins in the small intestine? Select one: a. enteropeptidase b. hexokinase c. papain d. pepsin e. secretin

The correct answer is: a. enteropeptidase

Which of these is NOT an intestinal protease? Select one: a. chymotrypsin b. elastase c. enteropeptidase d. pepsin e. trypsin

The correct answer is: d. pepsin

Which of the following is a zymogen that can be converted to an endopeptidase that hydrolyzes peptide bonds adjacent to Lys and Arg residues? Select one: a. chymotrypsinogen b. pepsin c. pepsinogen d. proelastase e. trypsinogen

The correct answer is: e. trypsinogen

In amino acid catabolism, the first reaction for many amino acids is a: Select one: a. decarboxylation requiring thiamine pyrophosphate (TPP). b. hydroxylation requiring NADPH and O2. c. oxidative deamination requiring NAD+. d. reduction requiring pyridoxal phosphate (PLP). e. transamination requiring pyridoxal phosphate

The correct answer is: e. transamination requiring pyridoxal phosphate.

The cofactor required for all transaminations is derived from: Select one: a. niacin. b. pyridoxine (vitamin B6). c. riboflavin d. thiamin. e. vitamin B12

The correct answer is: b. pyridoxine (vitamin B6).

The cofactor involved in a transaminase reaction is: Select one: a. biotin phosphate. b. lipoic acid. c. nicotinamide adenine dinucleotide phosphate (NADP+). d. pyridoxal phosphate (PLP) e. thiamine pyrophosphate (TPP)

The correct answer is: d. pyridoxal phosphate (PLP)

Transamination of alanine to alpha-ketoglutarate requires the cofactor: Select one: a. thiamine pyrophosphate (TPP). b. pyridoxal phosphate (PLP). c. No coenzyme is involved. d. NADH. e. biotin.

The correct answer is: b. pyridoxal phosphate (PLP).

Pyridoxal phosphate is a cofactor in this class of reactions: Select one: a. transamination. b. reduction. c. methylation. d. desulfuration. e. acetylation.

The correct answer is: a. transamination.

Which of the following is not true for the reaction catalyzed by glutamate dehydrogenase? Select one: a. The reaction is similar to transamination in that it involves the coenzyme pyridoxal phosphate (PLP). b. The enzyme is specific for glutamate. c. The enzyme can use either NAD+ or NADP+ as a cofactor. d. NH4+ is produced. e. alpha-ketoglutarate is produced

The correct answer is: a. The reaction is similar to transamination in that it involves the coenzyme pyridoxal phosphate (PLP).

Glutamate is metabolically converted to alpha-ketoglutarate and NH4+ by a process described as: Select one: a. transamination. b. reductive deamination. c. hydrolysis. d. deamidation e. oxidative deamination

The correct answer is: e. oxidative deamination

The conversion of glutamate to an alpha-ketoacid and NH4+: Select one: a. does not require any cofactors. b. is a reductive deamination. c. is accompanied by ATP hydrolysis catalyzed by the same enzyme. d. is catalyzed by glutamate dehydrogenase. e. requires ATP.

The correct answer is: d. is catalyzed by glutamate dehydrogenase.

Which substance is NOT involved in the production of urea from NH4+ via the urea cycle? Select one: a. ornithine b. malate c. carbamoyl phosphate d. ATP e. aspartate

The correct answer is: b. malate

A nitrogen atom of which compound is incorporated in the urea by an enzyme of the urea cycle? Select one: a. ornithine b. glutamate c. carnitine d. aspartate e. adenine

The correct answer is: e. aspartate

Conversion of ornithine to citrulline is a step in the synthesis of: Select one: a. urea. b. tyrosine. c. pyruvate. d. carnitine. e. aspartate.

The correct answer is: a. urea.

In the urea cycle, ornithine transcarbamoylase catalyzes: Select one: a. cleavage of urea to ammonia. b. formation of citrulline from ornithine and another reactant. c. formation of ornithine from citrulline and another reactant. d. formation of urea from arginine. e. transamination of arginine.

The correct answer is: b. formation of citrulline from ornithine and another reactant.

The amino acids serine, alanine, and cysteine can be catabolized to yield: Select one: a. succinate. b. pyruvate. c. oxaloacetate d. fumarate. e. alpha-ketoglutarate.

The correct answer is: b. pyruvate.

Serine or cysteine may enter the citric acid cycle as acetyl-CoA after conversion to: Select one: a. oxaloacetate. b. propionate. c. pyruvate. d. succinate. e. succinyl-CoA.

The correct answer is: c. pyruvate.

The human genetic disease phenylketonuria (PKU) can result from: Select one: a. inability to convert phenylalanine to tyrosine. b. deficiency of protein in the diet. c. inability to catabolize ketone bodies. d. inability to synthesize phenylalanine. e. production of enzymes containing no phenylalanine.

The correct answer is: a. inability to convert phenylalanine to tyrosine.

Nonessential amino acids: Select one: a. may be substituted with other amino acids in proteins. b. can be synthesized in humans. c. are synthesized by plants and bacteria, but not by humans. d. are not utilized in mammalian proteins. e. cannot be converted to intermediates of the citric acid cycle

The correct answer is: b. can be synthesized in humans.

Glutamine, arginine, and proline: Select one: a. do not have a common precursor in their synthesis b. may all be derived from a citric acid cycle intermediate. c. may all be derived from a glycolytic intermediate. d. may all be derived from an urea cycle intermediate.

The correct answer is: b. may all be derived from a citric acid cycle intermediate.

Delta-aminolevulinic acid is formed from succinyl-CoA and __________ and is an intermediate in the biosynthesis of \_\_\_\_\_\_\_\_\_. Select one: a. serine; sphingosine b. serine; heme c. acetyl-CoA; long chain fatty acids d. alpha-ketoglutarate; glutamate and proline e. glycine; porphyrin

The correct answer is: e. glycine; porphyrin

Glutathione is a: Select one: a. product of glutamate and methionine. b. tripeptide of glycine, glutamate, and cysteine. c. enzyme essential in the synthesis of glutamate. d. methyl-group donor in many biosynthetic pathways.

The correct answer is: b. tripeptide of glycine, glutamate, and cysteine.

Which amino acid is not directly involved in the purine biosynthetic pathway? Select one: a. alanine. b. aspartate. c. glutamine. d. glycine.

The correct answer is: a. alanine.

What is not true among the following statements concerning biotransformation Select one or more: a. biotransformation results in formation of ATP b. biotransformation is an intermediary metabolism process c. biotransformation is often called drug metabolism d. biotransformation processes usually require cofactors

The correct answers are: a. biotransformation results in formation of ATP b. biotransformation is an intermediary metabolism process

What is true among the following statements concerning the possible fates of xenobiotics Select one or more: a. they can be converted by enzymes b. they can be eliminated without chemical reactions c. they can be converted spontaneously d. they can be accumulated

The correct answers are: a. they can be converted by enzymes b. they can be eliminated without chemical reactions c. they can be converted spontaneously d. they can be accumulated

What is/are not true among the following statements concerning drug metabolism Select one: a. conjugation is a first phase reaction in biotransformation b. usually fat soluble substrates become water soluble c. in the preparatory phase usually reactive intermediates are formed d. the conjugated derivatives are usually inactivated

The correct answer is: a. conjugation is a first phase reaction in biotransformation

What is true among the following statements: In the cytochrome P450 system Select one or more: a. NADPH is required b. electrons are transferred in two steps c. flavoproteins are involved d. superoxide anions can be formed

The correct answers are: a. NADPH is required b. electrons are transferred in two steps c. flavoproteins are involved d. superoxide anions can be formed

Cytochrome P450 enzymes can be expressed Select one or more: a. only in the liver b. in several cell types c. mainly in the liver but also in other tissues d. in the cytosol

The correct answers are: b. in several cell types c. mainly in the liver but also in other tissues

Drugs can be conjugated Select one or more: a. by glucuronidation b. by acetylation c. with glutathion d. by sulfation

The correct answers are: a. by glucuronidation b. by acetylation c. with glutathion d. by sulfation

What is true among the following statements concerning cytochrome P450 inducers Select one or more: a. polycyclic aromatic hydrocarbons can be inducers b. dioxin is a powerful carcinogen c. nitrosamine derivatives can cause chemical carcinogenesis d. can stimulate proliferation of endoplasmic reticulum e. cannot be drug metabolism substrates

The correct answers are: a. polycyclic aromatic hydrocarbons can be inducers, b. dioxin is a powerful carcinogen, c. nitrosamine derivatives can cause chemical carcinogenesis, d. can stimulate proliferation of endoplasmic reticulum

The straight glucose chains of glycogen molecules are broken down initially to Select one: a. glucose b. glucose- 6- phosphate c. glucose-1- phosphate d. fructose diphosphate e. UDP-glucose

The correct answer is: c. glucose-1- phosphate

The branch points of glycogen are broken down to Select one: a. fructose diphosphate b. glucose c. glucose- 1- phosphate d. glucose -6- phosphate e. UDP-glucose

The correct answer is: b. glucose

The straight chains of glycogen molecules are broken down by Select one: a. adenylate cyclase b. glycogen glicosidase c. glycogen phosphorylase d. glycogen-glycosidase e. protein kinase

The correct answer is: c. glycogen phosphorylase

The debranching enzyme possesses the following activity(ies) Select one: a. A transferase activity b. Both debranching and a transferase activity c. Debranching activity d. Elongase activity e. Neither a debranching and a transferase activity

The correct answer is: b. Both debranching and a transferase activity

Glucagon Select one: a. inhibits the formation of glycogen and stimulates the breakdown of glycogen b. simultaneously inhibits the formation of glycogen and glycogen breakdown c. simultaneously stimulates the formation of glycogen and glycogen breakdown d. simultaneously stimulates the formation of glycogen and ketone bodies e. stimulates the formation of glycogen and inhibits the breakdown of glycogen

The correct answer is: a. inhibits the formation of glycogen and stimulates the breakdown of glycogen

Epinephrine Select one: a. stimulates the formation of glycogen and inhibits the breakdown of glycogen b. simultaneously stimulates the formation of glycogen and ketone bodies c. simultaneously stimulates the formation of glycogen and glycogen breakdown d. simultaneously inhibits the formation of glycogen and glycogen breakdown e. inhibits the formation of glycogen and stimulates the breakdown of glycogen

The correct answer is: e. inhibits the formation of glycogen and stimulates the breakdown of glycogen

Insulin Select one: a. stimulates the formation of glycogen and inhibits the breakdown of glycogen b. simultaneously stimulates the formation of glycogen and ketone bodies c. simultaneously stimulates the formation of glycogen and glycogen breakdown d. simultaneously inhibits the formation of glycogen and glycogen breakdown e. inhibits the formation of glycogen and stimulates the breakdown of glycogen

The correct answer is: a. stimulates the formation of glycogen and inhibits the breakdown of glycogen

Glucagon Select one: a. activates glycogen phosphorylase and increases the rate of glycogen synthesis b. activates glycogen phosphorylase and increases the rate of glycogen breakdown c. activates phosphofruktokinase 1 and increases the rate of gluconeogenesis d. deactivates glycogen phosphorylase and decreases the rate of glycogen synthesis e. deactivates glycogen phosphorylase and increases the rate of glycogen synthesis

The correct answer is: b. activates glycogen phosphorylase and increases the rate of glycogen breakdown

Insulin Select one: a. activates phosphofruktokinase 2 and increases the rate of gluconeogenesis b. decreases the activity of glycogen synthase and decreases the rate of glycogen synthesis c. decreases the activity of glycogen synthase and increases the rate of glycogen synthesis d. increases the activity of glycogen synthase and decreases the rate of glycogen synthesis e. increases the activity of glycogen synthase and increases the rate of glycogen synthesis

The correct answer is: e. increases the activity of glycogen synthase and increases the rate of glycogen synthesis

The binding of epinephrine to a receptor Select one: a. deactivates protein kinase A b. deactivates adenylate cyclase c. causes the breakdown of cyclic AMP to ATP d. activates phosphodiesterase e. activates adenylate cyclase

The correct answer is: e. activates adenylate cyclase

The binding of glucagon to its receptor Select one: a. deactivates protein kinase b. deactivates adenylate cyclase c. causes the breakdown of cyclic AMP to ATP d. activates adenylate cyclase e. activates phosphodiesterase

The correct answer is: d. activates adenylate cyclase

Protein kinase A Select one: a. removes a phosphate molecule from glycogen synthase b. removes a phosphate molecule from cAMP c. adds a phosphate to fructose-6-phosphate d. adds a phosphate molecule to glycogen synthase e. adds a phosphate molecule to cAMP

The correct answer is: d. adds a phosphate molecule to glycogen synthase

Protein kinase A Select one: a. adds a phosphate molecule to phosphorylase kinase b. adds a phosphate molecule to glycogen phosphorylase c. adds a phosphate to glucokinase d. removes a phosphate molecule from glycogen phosphorylase e. removes a phosphate molecule from phosphorylase kinase

The correct answer is: a. adds a phosphate molecule to phosphorylase kinase

Protein kinase A Select one: a. Directly activates glycogen phosphorilase b. activates glycogen synthase c. converts ATP to cAMP d. converts cAMP to ATP e. deactivates glycogen synthase

The correct answer is: e. deactivates glycogen synthase

In glycogenesis, the enzyme (i)\_\_\_\_\_\_\_\_ uses a molecule of (ii)\_\_\_\_\_\_\_\_\_ to lengthen the glycogen chain Select one: a. (i) glycogen synthase (ii) glucose b. (i)glycogen phosphorylase (ii) glucose c. (i) glycogen phosphorylase (ii) UDP-glucose d. (i) glycogen synthase (ii) UDP-glucose e. (i) glycogenin (ii) glucose-1-phosphate

The correct answer is: d. (i) glycogen synthase (ii) UDP-glucose

A person is suffering from a disease which is caused by a defective glucose-6-phosphatase. Such a person Select one: a. can breakdown glycogen completely to glucose b. can convert pyruvate to glucose c. can dephosphorylate glucose-6-phosphate d. can convert glycogen to pyruvate e. can convert acetyl-CoA to glucose

The correct answer is: b. can convert glycogen to pyruvate

A person is suffering from a disease in which is caused by a defective glucose-6-phosphatase. Such a person Select one: a. can convert acetyl-CoA to glucose b. cannot breakdown glycogen completely to glucose c. cannot convert acetyl-CoA to citric acid d. cannot convert glycogen to pyruvate e. would suffer no ill-effects from this defect

The correct answer is: b. cannot breakdown glycogen completely to glucose

In glycogenolysis, the enzyme (i)\_\_\_\_\_\_\_\_ breaks an (ii) _______ bond to release a molecule of (iii)\_\_\_\_\_\_\_\_\_. Select one: a. (i) glycogen synthase (ii) alpha 1-4 (iii) glucose b. (i) glycogen synthase (ii) alpha 1-4 (iii) UDP-glucose c. (i) glycogen phosphorylase (ii) alpha 1-4 (iii) glucose-1-phosphate d. (i) glycogen phosphorylase (ii) alpha 1-6 (iii) glucose-6-phosphate e. (i) debranching enzyme (ii) alpha 1-6 (iii) glucose-1-phosphate

The correct answer is: c. (i) glycogen phosphorylase (ii) alpha 1-4 (iii) glucose-1-phosphate

Which enzyme catalyzes the first ATP producing step of glycolysis? Select one: a. phosphofructokinase 1 b. hexokinase c. pyruvate kinase d. phosphoglycerate mutase e. phosphoglycerate kinase

The correct answer is: e. phosphoglycerate kinase

Which enzyme catalyzes the second ATP producing step of glycolysis? Select one: a. phosphofructokinase 1 b. hexokinase c. pyruvate kinase d. phosphoglycerate mutase e. phosphoglycerate kinase

The correct answer is: c. pyruvate kinase

Upon phosphorylation of phosphofructokinase 2 by protein kinase A in liver: Select one: a. it becomes active. b. it becomes inactive. c. phosphatase function is activated, kinase function is inactivated. d. kinase function is activated, phosphatase function is inactivated. e. phosphofructokinase 2 is not covalently regulated.

The correct answer is: c. phosphatase function is activated, kinase function is inactivated.

The allosteric activator of pyruvate carboxylase is: Select one: a. oxaloacetate b. NADH c. CoA d. ATP e. acetyl-coA

The correct answer is: e. acetyl-coA

When is the glycogen pool of the liver depleted during fasting? Select one: a. in 6 hours b. in 1 hour c. in 24 hours d. in 3 days e. in a week

The correct answer is: c. in 24 hours

# Choose the enzyme, the lack of which leads to fructose intolerance Select one: a. aldolase A (fructose 1,6-bisphosphate aldolase) b. aldolase B (fructose 1-phosphate aldolase) c. fructokinase d. hexokinase e. phosphofructokinase

The correct answer is: b. aldolase B (fructose 1-phosphate aldolase)

Glycolysis in the erythrocyte produces pyruvate that is further metabolized to: Select one: a. CO2. b. lactate. c. glucose. d. hemoglobin. e. ethanol.

The correct answer is: b. lactate.

The conversion of 1 mol of fructose 1,6-bisphosphate to 2 mol of pyruvate by the glycolytic pathway results in a net formation of: Select one: a. 2 mol of NADH and 4 mol of ATP. b. 2 mol of NADH and 2 mol of ATP. c. 2 mol of NAD+ and 4 mol of ATP. d. 1 mol of NADH and 1 mol of ATP. e. 1 mol of NAD+ and 2 mol of ATP.

The correct answer is: a. 2 mol of NADH and 4 mol of ATP.

Which substrates are necessary for the synthesis of bile salts? Select one or more: a. NADPH2 b. NADH2 c. ATP d. O2 e. H2O

The correct answers are: a. NADPH2, c. ATP, d. O2

What is the subcellular localization of the side chain cleavage enzyme in adrenal fascicular cells? Select one: a. Golgi membranes b. mitochondria c. nuclear membrane d. plasma membrane e. rough endoplasmic reticulum

The correct answer is: b. mitochondria

What is the weakly androgenic steroid that is synthesized in the fascicular zone of the adrenal gland? Select one: a. testosterone b. progesterone c. pregnenolone d. dehydroepiandrosterone e. corticosterone

The correct answer is: d. dehydroepiandrosterone

Select the statements valid for the lipoproteins Select one or more: a. Their density increases in parallel with their protein content b. Their density is reciprocally proportional to their lipid content c. The core non-polar lipids are surrounded by polar lipids d. All of them contain phospholipids e. Non-polar interactions bind together the lipids in their structure

The correct answers are: a. Their density increases in parallel with their protein content, b. Their density is reciprocally proportional to their lipid content, c. The core non-polar lipids are surrounded by polar lipids, d. All of them contain phospholipids, e. Non-polar interactions bind together the lipids in their structure

Which of the following statements are valid for the apolipoprotein B-100? Select one or more: a. It is synthesized in the liver b. It is recognized by the LDL-receptor c. It is not present in the structure of VLDL d. It participates in the liver uptake of chylomicron remnants e. It is found in the structure of IDL

The correct answers are: a. It is synthesized in the liver, b. It is recognized by the LDL-receptor, e. It is found in the structure of IDL

Which of the following lipoproteins does not contain triacylglycerols? Select one: a. Chylomicron b. HDL3 c. IDL d. Nascent VLDL e. VLDL

The correct answer is: b. HDL3

Which of the following statements is not valid for the lipoprotein lipase? Select one: a. An isoenzyme with a low KM is present in the mammary gland b. It degrades the majority of plasma triacylglycerols c. It is bound to the luminal surface of the capillary endothelial cells d. Its activity increases in the fasting state e. VLDL carries its cofactor

The correct answer is: d. Its activity increases in the fasting state

Which of the following statements are valid? Select one or more: a. The nascent VLDL is formed in the intestinal epithelial cells b. The VLDL is converted to IDL in the circulation c. The cells recognize the apo B-100 in the structure of VLDL and take up the lipoprotein through it d. The lipoprotein lipase reduces the triacylglycerol content of VLDL e. The apo B-100 of LDL is derived from VLDL

The correct answers are: b. The VLDL is converted to IDL in the circulation, d. The lipoprotein lipase reduces the triacylglycerol content of VLDL, e. The apo B-100 of LDL is derived from VLDL

Which of the following statements is not valid? Select one: a. Cholesterol overload inhibits the expression of LDL-receptors b. Cholesterol overload inhibits the HMG-CoA reductase in the cells c. In case of cholesterol overproduction cholesteryl esters are formed in the cells as a result of the action of LCAT enzyme d. The LDL-derived cholesterol affects the cholesterol synthesis in the cells e. The LDL-receptor recognizes the apo B-100

The correct answer is: c. In case of cholesterol overproduction cholesteryl esters are formed in the cells as a result of the action of LCAT enzyme

Select the statements valid for the bile acids Select one or more: a. The bile acids are synthesized in the intestine b. In the course of synthesis the polar character of the molecules increases c. Bile acids are necessary for the solubilization of cholesterol in water phase d. Deoxycholic acid is one of the primary bile acids e. Lack of bile acids results in steatorrhea

The correct answers are: b. In the course of synthesis the polar character of the molecules increases, c. Bile acids are necessary for the solubilization of cholesterol in water phase, e. Lack of bile acids results in steatorrhea

Which is the committed step of the cholesterol biosynthesis? Select one: a. Mevalonate to 5-phosphomevalonate b. Acetyl-CoA to acetoacetyl-CoA c. Acetoacetyl-CoA to 3-hydroxi-3-methyl glutaryl-CoA d. 5-phosphomevalonate to 5-pyrophosphomevalonate e. 3-hydroxi-3-methyl glutaryl-CoA to Mevalonate

The correct answer is: e. 3-hydroxi-3-methyl glutaryl-CoA to Mevalonate

Select the correct statements Select one or more: a. The nascent HDL does not contain cholesteryl esters b. Triacylglycerols are transferred from VLDL to HDL c. Cholesteryl esters are transferred from VLDL to HDL d. The hepatic lipase degrades the triacylglycerols in HDL2 e. The HDL-derived cholesterol is taken up by the liver in part in the form of LDL

The correct answers are: a. The nascent HDL does not contain cholesteryl esters, b. Triacylglycerols are transferred from VLDL to HDL, d. The hepatic lipase degrades the triacylglycerols in HDL2, e. The HDL-derived cholesterol is taken up by the liver in part in the form of LDL

Select the wrong statement Select one: a. HDL carries ACAT (acyl-CoA cholesterol acyltransferase) b. HDL takes up triacylglycerols with the help of cholesteryl ester transfer protein c. HDL2 delivers cholesterol to the liver d. The HDL contains apo-A1 e. The triacylglycerol content of HDL2 is higher than that of HDL3

The correct answer is: a. HDL carries ACAT (acyl-CoA cholesterol acyltransferase)

At least how many glucose molecules are necessary to provide the carbon atoms for the biosynthesis of one cholesterol molecule in mammalian tissues? Select one: a. 7 b. 8 c. 9 d. 6 e. 5

The correct answer is: c. 9

Which of the following statements are valid for the ABCA1 transporter? Select one or more: a. It is the major transporter of bile salts b. Its deficiency causes atherosclerosis because of the elevated levels of LDL-cholesterol c. High intracellular cholesterol content stimulates its transcription d. It is necessary for the efflux of cholesterol from the cells e. It is a scavenger receptor for LDL f. HDL binds to it

The correct answers are: c. High intracellular cholesterol content stimulates its transcription, d. It is necessary for the efflux of cholesterol from the cells, f. HDL binds to it

Which processes are modulated by the amount of intracellular free cholesterol? Select one or more: a. synthesis of bile acids b. down-regulation of LDL-receptors in the membrane c. transfer of cholesterol from the membrane into HDL d. cholesterol synthesis e. synthesis of cholesterol esters

The correct answers are: a. synthesis of bile acids, b. down-regulation of LDL-receptors in the membrane, c. transfer of cholesterol from the membrane into HDL, d. cholesterol synthesis, e. synthesis of cholesterol esters

Which carbon atom carries the hydroxylic group in cholesterol? Select one: a. C-3 b. C-7 c. C-10 d. C-21 e. C-27

The correct answer is: a. C-3

Which statements are true? Select one or more: a. Cholesterol is formed from HMG-CoA synthesized in the mitochondria b. Cholesterol is formed from HMG-CoA synthesized in the cytosol c. Mevalonate is formed from HMG-CoA by decarboxylation d. NADPH is needed for mevalonate synthesis e. Acetyl-CoA for cholesterol synthesis originates from mitochondria

The correct answers are: b. Cholesterol is formed from HMG-CoA synthesized in the cytosol, d. NADPH is needed for mevalonate synthesis, e. Acetyl-CoA for cholesterol synthesis originates from mitochondria

Cholesterol is synthesized from: Select one: a. oxalate. b. malate. c. lipoic acid. d. choline. e. acetyl-CoA.

The correct answer is: e. acetyl-CoA.

Which of these statements about the regulation of cholesterol synthesis is not true? Select one: a. Cholesterol acquired in the diet has essentially no effect on the synthesis of cholesterol in the liver. b. Failure to regulate cholesterol synthesis predisposes humans to atherosclerosis. c. High intracellular cholesterol stimulates formation of cholesterol esters. d. Insulin stimulates HMG-CoA reductase. e. Cholesterol exerts a negative feedback effect on HMG-CoA reductase.

The correct answer is: a. Cholesterol acquired in the diet has essentially no effect on the synthesis of cholesterol in the liver.

Where is acyl-CoA cholesterol-transferase (ACAT) localized? Select one: a. endoplasmic reticulum membrane b. cytosol c. mitochondrium matrix d. inner mitochondrial membrane

The correct answer is: a. endoplasmic reticulum membrane

Which process is inhibited, if MTP (microsomal TG transfer protein) inhibitor is used as a drug? Select one: a. TG (triglyceride) transfer into adipocytes b. TG (triglyceride) transfer into hepatocytes c. cholesteryl ester transfer into lipid droplets d. cholesteryl ester transfer into chylomicrons

The correct answer is: d. cholesteryl ester transfer into chylomicrons

How many Acetyl-CoA molecules are needed for the synthesis of one molecule of cholesterol? Select one: a. 10 b. 18 c. 20 d. 25

The correct answer is: b. 18

Where is the SREBP regulator domain localized if there is excess cholesterol in the cell? Select one: a. cytosol b. endoplasmic reticulum c. Golgi d. nucleus

The correct answer is: b. endoplasmic reticulum

Which protein of the SREBP-dependent signalling binds directly cholesterol? Select one: a. SCAP b. SREBP c. INSIG d. SREBP-cleavage protease

The correct answer is: a. SCAP

What is the consequence of increased release of PCSK9? Select one: a. enhanced LDL uptake in hepatocytes b. increased number of LDL receptors in hepatocytes c. lower blood plasma LDL level d. higher blood plasma LDL level

The correct answer is: d. higher blood plasma LDL level

What is the consequence of enhanced IDOL production in the liver? Select one: a. enhanced LDL uptake in the liver b. higher number of LDL-receptors in the hepatocytes c. higher blood plasma LDL level d. lower blood plasma LDL level

The correct answer is: c. higher blood plasma LDL level

What is the function of the cholesteryl ester transfer protein (CETP)? Select one: a. transfers cholesteryl esters from extrahepatic cells to HDL b. transfers cholesteryl esters from HDL to VLDL c. transfers cholesteryl esters from the intestine to HDL d. transfers cholesteryl esters from HDL to the liver

The correct answer is: b. transfers cholesteryl esters from HDL to VLDL

What is the function of scavenger receptor B1 (SR-B1)? Select one: a. LDL endocytosis b. HDL endocytosis c. selective uptake of LDL-cholesterol d. selective uptake of HDL-cholesterol

The correct answer is: d. selective uptake of HDL-cholesterol

What chemical changes occur when primary bile acids are converted to secondary bile acids? Select one: a. removal of carboxylic groups b. reduction of the double bond at 3C c. removal of the 3C-hydroxylic group d. removal of the 7C-hydroxylic group

The correct answer is: d. removal of the 7C-hydroxylic group

Which value approaches most closely the daily rate of cholesterol synthesis in the liver (X) and in the extrahepatic tissues (Y) in adults (70 kg body weight)? Numbers are in mg cholesterol synthesized per kg organ mass. Select one: a. X=10; Y=1000 b. X=100; Y=100 c. X=250; Y=10 d. X=500; Y=1 e. X=1000; Y=0

The correct answer is: c. X=250; Y=10

Which proteins are needed for the transfer of dietary cholesterol to extrahepatic tissues? Select one or more: a. apoB48 b. apoB100 c. lipoprotein lipase d. acyl-CoA cholesterol acyl transferase e. lecithin cholesterol acyl transferase

The correct answers are: a. apoB48, b. apoB100, c. lipoprotein lipase, d. acyl-CoA cholesterol acyl transferase

Which statements are true concerning proprotein convertase subtilisin-like/kexin type 9 (PCSK9)? Select one or more: a. it contributes to the intracellular processing of LDL receptors prior their exposure in the membrane b. it stimulates the degradation of LDL receptors c. it triggers the endocytosis of LDL-receptor d. it binds to LDL receptors e. it is a protease that degrades LDL receptors

The correct answers are: b. it stimulates the degradation of LDL receptors, c. it triggers the endocytosis of LDL-receptor, d. it binds to LDL receptors

Which statements are true concerning Idol (inducer of degradation of LDL receptor)? Select one or more: a. it is a transcription factor controlling PCSK9 (proprotein convertase subtilisin-like/kexin type 9) b. it is a protease that degrades LDL receptor c. it binds LDL receptors extracellularly d. it is under the control of LXR (liver X receptor) e. it stimulates the ubiquitination of LDL receptor

The correct answers are: d. it is under the control of LXR (liver X receptor), e. it stimulates the ubiquitination of LDL receptor

Which statements are true concerning FXR (farnesoid X receptor)? Select one or more: a. it operates in fibroblasts, hepatocytes and intestinal epithelial cells b. its ligands are bile acids c. in fibroblasts it induces FGF19 (fibroblast growth factor 19) d. in hepatocytes it induces 7a-hydoxylase e. in intestinal epithelial cells it induces IBAT (ileal bile acid transporter)

The correct answers are: b. its ligands are bile acids, e. in intestinal epithelial cells it induces IBAT (ileal bile acid transporter)

Which statements are true concerning miR-33 microRNA? Select one or more: a. its level increases in cholesterol depletion b. its level increases in cholesterol overload c. it stimulates the translation of ABCA1 (ATP binding cassette A 1 transporter) d. it stimulates the transcription of NPC1 (Nieman-Pick type C 1 protein) e. it suppresses the translation of ABCA1 (ATP binding cassette A 1 transporter)

The correct answers are: a. its level increases in cholesterol depletion, e. it suppresses the translation of ABCA1 (ATP binding cassette A 1 transporter)

Select the factors that cause increase of the plasma LDL-cholesterol level Select one or more: a. LDL-receptor deficiency b. Apo-B100 deficiency c. lipoprotein lipase deficiency d. PCSK9 (proprotein convertase subtilisin-like/kexin type 9) deficiency e. Idol (inducer of degradation of LDL receptor) deficiency

The correct answers are: a. LDL-receptor deficiency, b. Apo-B100 deficiency

What is the biological role of bile acids? Select one or more: a. they contribute to the interfacial activation of pancreatic lipase in the intestine b. their micelles are essential for cholesterol absorption in the intestine c. they are ligands of FXR (farnesoid X receptor) d. their micelles are essential for cholesterol disposal in the intestine e. they are ligands of LXR (liver X receptor)

The correct answers are: a. they contribute to the interfacial activation of pancreatic lipase in the intestine, b. their micelles are essential for cholesterol absorption in the intestine, c. they are ligands of FXR (farnesoid X receptor), d. their micelles are essential for cholesterol disposal in the intestine

Which reactions participate in the bile acid synthesis? Select one or more: a. 7alfa hydroxylation b. 7beta hydroxylation c. 12alfa hydroxylation d. glycine conjugation e. glutamine conjugation

The correct answers are: a. 7alfa hydroxylation, c. 12alfa hydroxylation, d. glycine conjugation

What is the recommended daily allowance of cholesterol in normal mixed-type diet of adults? Select one: a. 0.5 g b. 1 g c. 2 g d. 10 g e. 100 g

The correct answer is: a. 0.5 g

In what form are the C-atoms of cholesterol released from the human body? Select one or more: a. CO2 b. free cholesterol c. cholesteryl esters d. cholate e. bilirubin

The correct answers are: a. CO2, b. free cholesterol, d. cholate

In what form is cholesterol released by the liver? Select one: a. chylomicron b. VLDL c. LDL d. IDL e. in complex with albumin

The correct answer is: b. VLDL

In what form is cholesterol taken up by the liver? Select one or more: a. chylomicron b. chylomicron remnant c. HDL d. LDL e. VLDL

The correct answers are: b. chylomicron remnant, c. HDL, d. LDL

Select the correct order of enzymes or transporters operating in the disposal of excess cholesterol from the human body? Select one: a. ABCA1 / LCAT / LDL / IDL / BSEP b. ABCA1 / LCAT / LDL / VLDL / BSEP c. ACAT / ABCA1 / HDL / LDL / BSEP d. ABCA1 / LCAT / HDL / CETP / LDL e. ABCA1 / ACAT / LCAT / HDL / LDL

The correct answer is: d. ABCA1 / LCAT / HDL / CETP / LDL

Which cells express FXR? Select one or more: a. hepatocytes b. enterocytes c. macrophages d. adipocytes e. smooth muscle cells

The correct answers are: a. hepatocytes, b. enterocytes

Which cells express LXR? Select one or more: a. hepatocytes b. enterocytes c. macrophages d. adipocytes e. smooth muscle cells

The correct answers are: a. hepatocytes, b. enterocytes, c. macrophages, d. adipocytes, e. smooth muscle cells

Which statements are true regarding the lecithin cholesterol acyl transferase? Select one or more: a. It is one of the enzymes of cholesterol synthesis. b. It forms cholesteryl esters. c. It is localized in the membrane of the endoplasmic reticulum. d. Apo AI is its activator. e. It is active in phosphorylated state.

The correct answers are: b. It forms cholesteryl esters. d. Apo AI is its activator.

Which statements are true regarding the synthesis of cholesterol in mammalians? Select one or more: a. Cholesterol is synthesized only in the liver. b. The rate of cholesterol synthesis is constant. c. Cholesterol inhibits the activity of 3-hydroxy 3-methyl glutaryl-CoA reductase d. Cholesterol inhibits the transcription of 3-hydroxy 3-methyl glutaryl-CoA reductase e. Cholesterol inhibits the degradation of 3-hydroxy 3-methyl glutaryl-CoA reductase

The correct answers are: c. Cholesterol inhibits the activity of 3-hydroxy 3-methyl glutaryl-CoA reductase, d. Cholesterol inhibits the transcription of 3-hydroxy 3-methyl glutaryl-CoA reductase

Which metabolic pathway uses the reaction catalyzed by 3-hydroxy 3-methyl glutaryl-CoA reductase? Select one: a. glycolysis b. synthesis of ketone bodies c. oxidation of fatty acids d. synthesis of fatty acids e. synthesis of cholesterol

The correct answer is: e. synthesis of cholesterol

Where is the 3-hydroxy 3-methyl glutaryl-CoA reductase localized within the cell? Select one: a. cytosol b. membrane of the endoplasmic reticulum c. matrix of mitochondria d. the inner membrane of mitochondria e. the outer membrane of mitochondria

The correct answer is: b. membrane of the endoplasmic reticulum

De novo synthesis of purine nucleotides utilizes: Select one or more: a. glutamine. b. components of the tetrahydrofolate one-carbon pool. c. aspartate. d. glycine.

The correct answers are: a. glutamine. b. components of the tetrahydrofolate one-carbon pool. c. aspartate. d. glycine.

The conversion of cholesterol to pregnenolone is a common reaction in the synthesis of adrenal steroid hormones. Which statements are true for the enzyme catalyzing this reaction? Select one or more: a. The enzyme uses biotin as a prosthetic group, which temporarily binds the side chain of cholesterol b. The enzyme is called ``side-chain cleavage enzyme'', and is a member of the family of cytochrom P450 isoenzymes c. The enzyme is localized to the cytosol, where it can easily access its substrate, cholesterol d. Cholesterol needs to be transported into the mitochondria for the reaction to take place e. The complete deficiency of this enzyme is lethal

The correct answers are: b. The enzyme is called ``side-chain cleavage enzyme'', and is a member of the family of cytochrom P450 isoenzymes, d. Cholesterol needs to be transported into the mitochondria for the reaction to take place, e. The complete deficiency of this enzyme is lethal

What is the role of StAR (Steroidogenic Acute Regulatory Protein) in the synthesis of steroid hormones? Select one or more: a. It is a protein required for the transport of cholesterol from the cytosol into the mitochondria b. Congenital lipoid adrenal hyperplasia is a lethal disease, where the mutations are localized to the StAR gene c. It is a protein required for the transport of cholesterol from the mitochondria to the cytosol, where cholesterol can be converted to pregnenolone d. In the adrenal cortex ACTH induces the synthesis of StAR, which is necessary for cortisol production e. In the adrenal cortex angiotensin II induces the synthesis of StAR, which is necessary for aldosterone production

The correct answers are: a. It is a protein required for the transport of cholesterol from the cytosol into the mitochondria, b. Congenital lipoid adrenal hyperplasia is a lethal disease, where the mutations are localized to the StAR gene, d. In the adrenal cortex ACTH induces the synthesis of StAR, which is necessary for cortisol production, e. In the adrenal cortex angiotensin II induces the synthesis of StAR, which is necessary for aldosterone production

Phosphoribosyl pyrophosphate is required for: Select one or more: a. the salvage of adenine b. the salvage of uridine c. conversion of purines to uric acid d. de novo synthesis of purine nucleotides

The correct answers are: a. the salvage of adenine, d. de novo synthesis of purine nucleotides

Select the cytochrom P450 isoenzymes! Select one or more: a. Side chain cleavage enzyme b. 21-Hydroxylase c. 11beta-hydroxy-steroid dehydrogenase d. 17-Hydroxylase e. 17-hydroxy-steroid dehydrogenase

The correct answers are: a. Side chain cleavage enzyme, b. 21-Hydroxylase, d. 17-Hydroxylase

Hypoxanthine-guanine phosphoribosyltransferase is an enzyme: Select one: a. for conversion of hypoxanthine to guanine b. for conversion of guanine to hypoxanthine c. required to convert hypoxanthine and guanine to urate d. participating in the synthesis of the purine ring e. required for the salvage of purine bases

The correct answer is: e. required for the salvage of purine bases

Select the correct statements regarding steroid hormone synthesis in the adrenal gland! Select one or more: a. Aldosterone is produced in the zona fasciculata cells b. Cortisol is produced in the zona fasciculata cells c. Testosterone is produced from estradiol by the aromatase enzyme d. The major products in the zona glomerulosa cells are the weak androgens e. The three layers of the adrenal cortex are specialized for the production of mineralocorticoids, glucocorticoids and estrogens

The correct answer is: a. Cortisol is produced in the zona fasciculata cells

In tissues where the de novo purine synthesis is not active, adenine nucleotides could be supplied by: Select one or more: a. adenine phosphoribosyl transferase b. ATP uptake from the blood c. nucleoside phosphorylase d. hypoxanthine-guanine phosphorybosyl transferase

The correct answers are: a. adenine phosphoribosyl transferase, d. hypoxanthine-guanine phosphorybosyl transferase

What are the signs of aldosterone deficiency? Select one or more: a. hypertension (elevated blood pressure) b. salt loss and dehydration c. elevated K+ concentration in blood d. loss of K+ with the urine e. red bumps on the toes

The correct answers are: b. salt loss and dehydration, c. elevated K+ concentration in blood

Thioredoxin is involved in the conversion of: Select one: a. hypoxantin to ATP. b. dUMP to dTMP. c. UTP to CTP. d. hypoxanthine and guanine to urate e. ribonucleotides to deoxyribonucleotides

The correct answer is: e. ribonucleotides to deoxyribonucleotides

Select the correct order of the enzymes in the de novo synthesis of orotic acid: Select one: a. Carbamoyl-phosphate synthetase/Asp transcarbamoylase/Dihydroorotase/Dihydroorotate dehydrogenase Dihydroorotase Dihydroorotase b. Dihydroorotase/Carbamoyl-phosphate synthetase/Asp transcarbamoylase/Dihydroorotate dehydrogenase c. Asp transcarbamoylase/Carbamoyl-phosphate synthetase/Dihydroorotase/Dihydroorotate dehydrogenase d. Dihydroorotase/Dihydroorotate dehydrogenase/Asp transcarbamoylase/Carbamoyl-phosphate synthetase/

The correct answer is: a. Carbamoyl-phosphate synthetase/Asp transcarbamoylase/Dihydroorotase/Dihydroorotate dehydrogenase Dihydroorotase Dihydroorotase

What is the role of the 11beta-hydroxysteroid dehydrogenase enzyme in the mineralocorticoid target cells? Select one: a. The enzyme inactivates cortisol b. The enzyme activates aldosterone c. The enzyme inactivates DOC (11-deoxycorticosterone) d. The enzyme activates DOC (11-deoxycorticosterone) e. The enzyme activates corticosterone

The correct answer is: a. The enzyme inactivates cortisol

What are the effects of aldosterone? Select one or more: a. Increases Na+-reabsorption in the kidney b. Increases K+-excretion in the kidney c. Promotes salt and water retention d. Promotes salt and water loss e. Induces the gene expression of Na+/K+-ATPase, as well as Na+-, and K+-channels in the kidney tubular cells

The correct answers are: a. Increases Na+-reabsorption in the kidney, b. Increases K+-excretion in the kidney, c. Promotes salt and water retention, e. Induces the gene expression of Na+/K+-ATPase, as well as Na+-, and K+-channels in the kidney tubular cells

The formation of dATP occurs primarily by: Select one: a. salvaging deoxyadenylate by a phosphoribosyltransferase b. salvaging deoxyadenosine by a phosphoribosyltransferase. c. converting ATP to dATP using NADH. d. converting ADP to dADP using thioredoxin. e. converting dIMP to dAMP using 5,10-methylene THF

The correct answer is: d. converting ADP to dADP using thioredoxin.

What are the correct statements regarding cortisol synthesis? Select one or more: a. Cortisol is synthesized exclusively in the zona glomerulosa of the adrenal cortex b. Cortisol is synthesized in the adrenal medulla c. Cortisol synthesis does not require the action of 17-hydroxylase d. The last step of cortisol synthesis is catalyzed by 11-hydroxylase e. Cortisol is synthesized from cholesterol

The correct answers are: d. The last step of cortisol synthesis is catalyzed by 11-hydroxylase, e. Cortisol is synthesized from cholesterol

Which of the following reactions will be inhibited by dihydrofolate analogues, such as methotrexates: Select one or more: a. de novo synthesis of UMP b. conversion of dUMP to dTMP. c. conversion of IMP to GMP d. de novo synthesis of IMP

The correct answers are: b. conversion of dUMP to dTMP. d. de novo synthesis of IMP

Aspartate is involved as a N-donor in: Select one or more: a. conversion of UTP to CTP. b. synthesis of AMP from IMP c. synthesis of GMP from IMP d. de novo synthesis of IMP

The correct answers are: b. synthesis of AMP from IMP, d. de novo synthesis of IMP

Which enzymes are not required for the synthesis of estrogens starting from cholesterol? Select one or more: a. 17-hydroxylase b. 21-hydroxylase c. 11-hydroxylase d. aromatase e. side chain cleavage enzyme

The correct answers are: b. 21-hydroxylase, c. 11-hydroxylase

Select the correct statements regarding the production of female sex steroids! Select one or more: a. The major site of estrogen production is the adrenal cortex b. Testosterone is converted to estradiol by aromatase, a cytochrome P450 isoenzyme c. The ovaries produce estradiol and progesterone d. In the placenta estradiol is synthesized from the weak androgen, DHEA provided by the maternal or fetal adrenal gland e. In the placenta estradiol is synthesized from LDL-cholesterol

The correct answers are: b. Testosterone is converted to estradiol by aromatase, a cytochrome P450 isoenzyme, c. The ovaries produce estradiol and progesterone, d. In the placenta estradiol is synthesized from the weak androgen, DHEA provided by the maternal or fetal adrenal gland

Select the correct statements regarding the production and inactivation of sex steroids! Select one or more: a. Leydig cells produce testosterone b. Testosterone can be reduced to dihydrotestosterone by a cytochrome P450 isoenzyme c. In the ovaries granulosa cells produce progesterone only in the luteal phase, after ovulation d. In the ovaries two cell types, the granulosa cell and the theca interna cell have to cooperate for the production of estradiol e. In the placenta the maternal steroid hormones are inactivated by a cytochrom P450 isoenzyme

The correct answers are: a. Leydig cells produce testosterone, c. In the ovaries granulosa cells produce progesterone only in the luteal phase, after ovulation, d. In the ovaries two cell types, the granulosa cell and the theca interna cell have to cooperate for the production of estradiol

If a cell has an adequate supply of adenine nucleotides but requires more guanine nucleotides: Select one or more: a. Glutamine-PRPP amidotransferase will not be fully inhibited. b. AMP will be a feedback inhibitor of the condensation of IMP with aspartate. c. ATP will stimulate the production of GMP from IMP. d. ATP will inhibit IMP dehydrogenase.

The correct answers are: a. Glutamine-PRPP amidotransferase will not be fully inhibited. b. AMP will be a feedback inhibitor of the condensation of IMP with aspartate. c. ATP will stimulate the production of GMP from IMP.

Select the correct statements regarding the synthesis of prostaglandins and thromboxanes! Select one or more: a. Arachidonic acid is an essential fatty acid, frequently found in membrane phospholipids b. Arachidonic acid is released from membrane phospholipids by phospholipase A2 c. PGH-synthase is a homodimer containing two different types of catalytic sites d. Arachidonic acid is converted to PGG2 by a peroxidase e. Platelets synthesize exclusively PGI2 from arachidonic acid

The correct answers are: b. Arachidonic acid is released from membrane phospholipids by phospholipase A2, c. PGH-synthase is a homodimer containing two different types of catalytic sites

Regulation of de novo AMP synthesis involves: Select one or more: a. allosteric activation by GMP b. allosteric inhibition by AMP c. availability of PRPP

The correct answers are: b. allosteric inhibition by AMP, c. availability of PRPP

Select the correct statements regarding the biological effects of prostaglandins and thromboxanes! Select one or more: a. TXA2 promotes platelet aggregation b. PGE2 promotes platelet aggregation c. PGE2 protects gastric mucosa cells from the erosive effects of gastric juice d. PGI2 inhibits platelet aggregation e. PGE2 and PGF2a play a role in the regulation of uterus contractility

The correct answers are: a. TXA2 promotes platelet aggregation, c. PGE2 protects gastric mucosa cells from the erosive effects of gastric juice, d. PGI2 inhibits platelet aggregation, e. PGE2 and PGF2a play a role in the regulation of uterus contractility

Orotic aciduria might be caused by the deficiency of: Select one or more: a. hypoxanthine-guanosine phosphoribosyl transferase b. UMP synthase c. adenosine deaminase d. Ornithine transcarbamoylase

The correct answers are: b. UMP synthase, d. Ornithine transcarbamoylase

How do the non-steroid anti-inflammatory drugs (NSAIDs) interfere with the synthesis of eicosanoids? Select one or more: a. Aspirin is a competitive inhibitor of the cyclooxygenase, COX-1 isoenzyme b. The cyclooxygenase, COX-1 isoenzyme is completely blocked after acetylation of a Ser residue in its substrate-binding pocket c. Aspirin prevents stroke in the elderly because it irreversibly acetylates the thromboxane synthase enzyme of platelets d. NSAIDs decrease the inflammatory reactions by reversibly blocking the conversion of LTA4 to LTB4 e. The selective blockage of the cyclooxygenase, COX-2 isoenzyme could be a good strategy for pain relief without the side effect of gastric bleeding

The correct answers are: b. The cyclooxygenase, COX-1 isoenzyme is completely blocked after acetylation of a Ser residue in its substrate-binding pocket, e. The selective blockage of the cyclooxygenase, COX-2 isoenzyme could be a good strategy for pain relief without the side effect of gastric bleeding

What are the correct statements regarding leukotrienes? Select one or more: a. The cysteinyl leukotrienes include LTC4, LTD4 and LTE4 b. LTA4 and LTB4 together form the ``slow-reacting substance of anaphylaxis'' that plays a major role in the pathogenesis of asthma bronchiale c. Montelukast (Singulair) and zafirlukast (Accolate) block the receptor for cysteinyl leukotrienes d. Leukotrienes are named after their capability to absorbe white light e. LTB4 is a chemotactic factor for neutrophil granulocytes

The correct answers are: a. The cysteinyl leukotrienes include LTC4, LTD4 and LTE4, c. Montelukast (Singulair) and zafirlukast (Accolate) block the receptor for cysteinyl leukotrienes, e. LTB4 is a chemotactic factor for neutrophil granulocytes

Which of the following conditions out of A-D can cause gout? Select one or more: a. mutation at the allosteric site of PRPP synthase b. glucose-6-phosphatase deficiency c. hypoxanthine-guanine phosphoribosyl transferase deficiency d. fructose intolerance e.

The correct answers are: a. mutation at the allosteric site of PRPP synthase, b. glucose-6-phosphatase deficiency, c. hypoxanthine-guanine phosphoribosyl transferase deficiency, d. fructose intolerance

Administration of allopurinol to a patient with gout, who has a normal HG-PRT level, would lead to all of the following EXCEPT: Select one: a. Decreased de novo synthesis of IMP. b. Decreased urate in the urine. c. An increase of hypoxanthine in the blood. d. Increased levels of PRPP . e. Increased xanthine in the blood.

The correct answer is: d. Increased levels of PRPP .

Which statements are true for the cyclooxygenase enzymes? Select one or more: a. the enzyme is also called PGH-synthase b. cyclooxygenases belong to the family of cytochrome P 450 isoenzymes c. arachidonate is a substrate for the enzyme d. aspirine inhibits cyclooxygenase activity e. in addition to the cyclooxygenase activity, the enzyme also exhibits epoxidase activity

The correct answers are: a. the enzyme is also called PGH-synthase, c. arachidonate is a substrate for the enzyme, d. aspirine inhibits cyclooxygenase activity

How many cyclooxygenase isoenzymes are known? Select one: a. 4 b. 3 c. 2 d. there are no isoforms of this enzyme e. there are no isoforms but the enzyme can exist in phosphorylated form

The correct answer is: c. 2

Which of the following statements is not true? Select one: a. The active form of cyclooxygenase is monomeric b. a serine residue of cyclooxygenase can be acetylated by aspirin c. aspirin blocks cyclooxygenase-1 by irreversible covalent modification d. Cyclooxygenase is a membrane-bound homodimeric enzyme e. each cyclooxygenase monomer contains two different active centers

The correct answer is: a. The active form of cyclooxygenase is monomeric

Which statements are valid for arachidonic acid? Select one or more: a. It can be released from phospholipids b. Phospholipase C catalyzes its release from the plasma membrane c. Prostaglandins are produced from arachidonic acid d. Cyclooxygenase catalyzes the synthesis of leukotrienes

The correct answers are: a. It can be released from phospholipids, c. Prostaglandins are produced from arachidonic acid

Prerequisites for thromboxane synthesis are: Select one or more: a. availability of phospholipid containing arachidonate for phospholipase A2 b. active lipoxygenase c. functional cyclooxygenase d. corticosteroids do not inhibit cyclooxygenase

The correct answers are: a. availability of phospholipid containing arachidonate for phospholipase A2, c. functional cyclooxygenase, d. corticosteroids do not inhibit cyclooxygenase

Which of these can be synthesized by plants but not by humans? Select one: a. linoleate [18:2(D9,12)] b. palmitate (16:0) c. phosphatidylcholine d. pyruvate e. stearate (18:0)

The correct answer is: a. linoleate [18:2(D9,12)]

Which of these statements about eicosanoid synthesis is true? Select one: a. An early step in the path to thromboxanes is blocked by aspirin b. Aspirin acts by blocking the synthesis of arachidonate. c. Plants can synthesize leukotrienes, but humans cannot. d. Thromboxanes are produced from arachidonate via the "lipoxygenase" path.

The correct answer is: a. An early step in the path to thromboxanes is blocked by aspirin

Which of the following is a definition of glycemic index? Select one: a. The decrease in the blood concentration of glucagon after consuming the food compared with an equivalent amount  of white bread. b. The increase in the blood concentration of glucose after  consuming the food. c. The increase in the blood concentration of glucose after  consuming the food compared with an equivalent amount of white bread. d. The increase in the blood concentration of insulin after  consuming the food. e. The increase in the blood concentration of insulin after  consuming the food compared with an equivalent amount of white bread.

The correct answer is: c. The increase in the blood concentration of glucose after  consuming the food compared with an equivalent amount of white bread.

Which of the following will have the lowest glycemic index? Select one: a. baked apple b. A baked potato c. An uncooked apple d. An uncooked potato e. Apple juice

The correct answer is: d. An uncooked potato

Which of the following will have the highest glycaemic index? Select one: a. A baked apple b. A baked potato c. An uncooked apple d. An uncooked potato e. Apple juice

The correct answer is: e. Apple juice

A blood sample is taken from a 50-year-old woman after an overnight fast. Which one of the following will be at a higher concentration than after she had eaten a meal? Select one: a. Glucose b. Insulin c. Ketone bodies d. Nonesterified fatty acids e. Triacylglycerol

The correct answer is: d. Nonesterified fatty acids

A blood sample is taken from a 25-year-old man after he has eaten three slices of toast and a boiled egg. Which one of the following will be at a higher concentration than if the blood sample had been taken after an overnight fast? Select one: a. Alanine b. Glucagon c. Glucose d. Ketone bodies e. Nonesterified fatty acids

The correct answer is: c. Glucose

A blood sample is taken from a40-year-old man has been fasting completely for a week, drinking only water. Which of the following will be at a higher concentration than after a normal overnight fast? Select one: a. Glucose b. Insulin c. Ketone bodies d. Nonesterified fatty acids e. Triacylglycerol

The correct answer is: c. Ketone bodies

Which one of following statements about the fed and fasting metabolic states is correct?  Select one: a. In the fasting state glucagon acts to increase the activity of lipoprotein lipase in adipose tissue. b. In the fasting state, glucagon acts to increase the synthesis of glycogen from glucose. c. In the fed state insulin acts to increase the breakdown of glycogen to maintain blood glucose. d. Ketone bodies are synthesized in liver in the fasting state, and the amount synthesized increase as fasting extends into starvation. e. In the fed state there is decreased secretion of insulin in response to increased glucose in the portal blood.

The correct answer is: d. Ketone bodies are synthesized in liver in the fasting state, and the amount synthesized increase as fasting extends into starvation.

Which one of following statements about the fed and fasting metabolic states is correct?  Select one: a. In the fed state muscle can take up glucose for use as a metabolic fuel because glucose transport in muscle is stimulated in response to glucagon. b. In the fed state there is decreased secretion of glucagon in response to increased glucose in the portal blood. c. In the fed state, glucagon acts to increase the synthesis of glycogen from glucose. d. Plasma glucose is maintained in starvation and prolonged fasting by gluconeogenesis from ketone bodies. e. There is an increase in metabolic rate in the fasting state.

The correct answer is: b. In the fed state there is decreased secretion of glucagon in response to increased glucose in the portal blood.

Which one of following statements about the fed and fasting metabolic states is correct? Select one: a. In the fasting state muscle synthesizes glucose from amino acids. b. In the fed state adipose tissue can take up glucose for synthesis of triacylglycerol because glucose transport in adipose tissue is stimulated in response to insulin. c. Ketone bodies are synthesized in muscle in the fasting state, and the amount synthesized increases as fasting extends into starvation. d. Ketone bodies provide an alternative fuel for red blood cells in the fasting state. e. Plasma glucose is maintained in starvation and prolonged fasting by gluconeogenesis from fatty acids.

The correct answer is: b. In the fed state adipose tissue can take up glucose for synthesis of triacylglycerol because glucose transport in adipose tissue is stimulated in response to insulin.

Which one of following statements about the fed and fasting metabolic states is correct? Select one: a. In the fasting state adipose tissue synthesizes glucose from  the glycerol released by the breakdown of triacylglycerol. b. In the fasting state adipose tissue synthesizes ketone bodies. c. In the fasting state the main fuel for red blood cells is fatty  acids released from adipose tissue. d. Ketone bodies provide the main fuel for the central nervous  system in the fasting state. e. Plasma glucose is maintained in starvation and prolonged fasting by gluconeogenesis in the liver from the amino acids released by the breakdown of muscle protein.

The correct answer is: e. Plasma glucose is maintained in starvation and prolonged fasting by gluconeogenesis in the liver from the amino acids released by the breakdown of muscle protein.

Which one of following statements about the fed and fasting metabolic states is correct? Select one: a. Fatty acids and triacylglycerol are synthesized in the liver in  the fasting state. b. In the fasting state the main fuel for the central nervous  system is fatty acids released from adipose tissue. c. In the fasting state the main metabolic fuel for most tissues  comes from fatty acids released from adipose tissue. d. In the fed state muscle cannot take up glucose for use as a  metabolic fuel because glucose transport in muscle is  stimulated in response to glucagon. e. Plasma glucose is maintained in starvation and prolonged  fasting by gluconeogenesis in adipose tissue from the glycerol released from triacylglycerol.

The correct answer is: c. In the fasting state the main metabolic fuel for most tissues  comes from fatty acids released from adipose tissue.

A 25-year-old man visits his GP complaining of abdominal cramps and diarrhea after drinking milk. What is the most likely cause of his problem? Select one: a. Bacterial and yeast overgrowth in the large intestine b. Infection with the intestinal parasite Giardia lamblia c. Lack of pancreatic amylase d. Lack of small intestinal lactase e. Lack of small intestinal sucrase-isomaltase

The correct answer is: d. Lack of small intestinal lactase

Which one of following statements about glycolysis and gluconeogenesis is correct? Select one: a. All the reactions of glycolysis are freely reversible for  gluconeogenesis. b. Fructose cannot be used for gluconeogenesis in the liver  because it cannot be phosphorylated to fructose-6-  phosphate. c. Glycolysis can proceed in the absence of oxygen only if  pyruvate is formed from lactate in muscle. d. Red blood cells only metabolize glucose by anaerobic  glycolysis (and the pentose phosphate pathway). e. The reverse of glycolysis is the pathway for gluconeogenesis  in skeletal muscle.

The correct answer is: d. Red blood cells only metabolize glucose by anaerobic  glycolysis (and the pentose phosphate pathway).

Which one of following statements about the step in glycolysis catalyzed by hexokinase and in gluconeogenesis by glucose 6-phosphatase is correct? Select one: a. Because hexokinase has a low Km its activity in liver  increases as the concentration of glucose in the portal  blood increases. b. Glucose-6-phosphatase is mainly active in muscle in the  fasting state. c. If hexokinase and glucose-6-phosphatase are both equally  active at the same time there is net formation of ATP from  ADP and phosphate. d. Liver contains an isoenzyme of hexokinase, glucokinase,  which is especially important in the fed state e. Muscle can release glucose into the circulation from its  glycogen reserves in the fasting state.

The correct answer is: d. Liver contains an isoenzyme of hexokinase, glucokinase,  which is especially important in the fed state

Which one of following statements about this step in glycolysis catalyzed by phosphofructokinase and in gluconeogenesis by fructose 1,6-bisphosphatase is correct? Select one: a. Fructose 1,6-bisphosphatase is mainly active in the liver in the fed state. b. If phosphofructokinase and fructose 1,6-bisphosphatase are both equally active at the same time, there is a net formation of ATP from ADP and phosphate. c. Phosphofructokinase is inhibited more or less completely by physiological concentrations of ATP. d. Phosphofructokinase is mainly active in the liver in the fasting state.

The correct answer is: c. Phosphofructokinase is inhibited more or less completely by physiological concentrations of ATP.

Which one of the following statements about glucose metabolism in maximum exertion is correct? Select one: a. Gluconeogenesis from lactate requires less ATP than is formed during anerobic glycolysis. b. In maximum exertion pyruvate is oxidized to lactate in muscle. c. Oxygen debt is caused by the need to exhale carbon dioxide produced in response to acidosis. d. Oxygen debt reflects the need to replace oxygen that has been used in muscle during vigorous exercise. e. There is metabolic acidosis as a result of vigorous exercise

The correct answer is: e. There is metabolic acidosis as a result of vigorous exercise

Which one of following statements about glycogen metabolism is correct? Select one: a. Glycogen is synthesized in the liver in the fed state, then exported to other tissues in low density lipoproteins. b. Glycogen reserves in liver and muscle will meet energy requirements for several days in prolonged fasting. c. Liver synthesizes more glycogen when the hepatic portal blood concentration of glucose is high because of the activity of glucokinase in the liver. d. Muscle synthesizes glycogen in the fed state because glycogen phosphorylase is activated in response to insulin. e. The plasma concentration of glycogen increases in the fed state.

The correct answer is: c. Liver synthesizes more glycogen when the hepatic portal blood concentration of glucose is high because of the activity of glucokinase in the liver.

Which one of following statements about glucose metabolism is correct? Select one: a. Glucagon increases the rate of glycolysis. b. Glycolysis requires NADP+. c. In glycolysis, glucose is cleaved into two three carbon compounds. d. Substrate level phosphorylation takes place in the electron transport system. e. The main product of glycolysis in red blood cells is pyruvate.

The correct answer is: c. In glycolysis, glucose is cleaved into two three carbon compounds.

Which one of following statements about glycogen metabolism is correct? Select one: a. Glycogen synthase activity is increased by glucagon. b. Glycogen phosphorylase is an enzyme that can be activated by phosphorylation of serine residues. c. Glycogen phosphorylase cannot be activated by calcium ions. d. cAMP activates glycogen synthesis. e. Glycogen phosphorylase breaks the α1-4 glycosidic bonds by hydrolysis.

The correct answer is: b. Glycogen phosphorylase is an enzyme that can be activated by phosphorylation of serine residues.

The proton motive force is the sum of: Select one: a. Proton gradient and electrical potential difference across the outer mitochondrial membrane b. Proton gradient and ATP gradient across the outer mitochondrial membrane c. Proton gradient and electrical potential difference across the inner mitochondrial membrane d. Proton gradient and ATP gradient across the inner mitochondrial membrane e. Electrical potential difference and ATP gradient across the inner mitochondrial membrane

The correct answer is: c. Proton gradient and electrical potential difference across the inner mitochondrial membrane

Which statement is false? Select one: a. Trypsin can cleave the peptide bond formed by the carboxyl group of a basic amino acid. b. Trypsin can cleave the peptide bond formed by the amino group of a basic amino acid. c. Chymotrypsin can cleave the peptide bond formed by the carboxyl group of aromatic amino acids. d. Chymotrypsin can cleave the peptide bond near tyrosine. e. Trypsin can cleave the peptide bond near lysine.

The correct answer is: b. Trypsin can cleave the peptide bond formed by the amino group of a basic amino acid.

Which of the following enzyme is not the component of the reagent for triglyceride determination? Select one: a. Peroxidase b. Glycerol kinase c. ACAT d. Glycerol-3-phosphate oxidase e. Lipoprotein lipase

The correct answer is: c. ACAT

Select the correct statement from the sentences below: Select one: a. Higher HDL-cholesterol level is accompanied with higher risk for myocardial infarct. b. Determination of LDL-cholesterol level is important for patients with familial and secondary hypercholesterinaemia. c. Cholesterol is only present in LDL and HDL liporpoteins. d. Hyperlipoproteinaemia is protective against cardiovascular diseases. e. Dyslipidaemia is an essential risk factor in bone diasesas.

The correct answer is: b. Determination of LDL-cholesterol level is important for patients with familial and secondary hypercholesterinaemia.

Which of the following enzymes is present in the reagent for cholesterol determination? Select one: a. Cholesterol esterase b. HMG-CoA-reductase c. LCAT d. Glycerol-3-phosphate oxidase e. Malate-dehydrogenase

The correct answer is: a. Cholesterol esterase

Select the correct statement for the determination of serum cholesterol! Select one: a. LDL-cholesterol level is determinded directly from the plasma-supernatant after precipitation of other lipoproteins. b. HDL-cholesterol level is determinded directly from the plasma-supernatant after precipitation of other lipoproteins. c. In the first step of cholesterol level determination, cholesterol-esthers will be hydrolised by cholesterol peroxidase. d. VLDL-cholesterol level is determinded directly from the plasma-supernatant after precipitation of other lipoproteins. e. Cholesterol determination is performed by the Biuret-reaction.

The correct answer is: b. HDL-cholesterol level is determinded directly from the plasma-supernatant after precipitation of other lipoproteins.

Which statement is false? Select one: a. Enzymatic hydrolysis of cholesteryl esters is needed for determination of HDL-cholesterol. b. Determination of HDL-cholesterol is needed for determination of LDL-cholesterol. c. Determination of HDL-cholesterol is needed for determination of total serum cholesterol. d. Determination of serum triglyceride is needed for determination of LDL-cholesterol. e. Precipitation and sedimentation of VLDL and LDL is needed for determination of HDL-cholesterol.

The correct answer is: c. Determination of HDL-cholesterol is needed for determination of total serum cholesterol.

Which statement is false? The enzymatic reactions involved in determination of LDL-cholesterol include: Select one: a. hydrolysis of cholesteryl esters by cholesteryl esterase b. hydrolysis of cholesteryl esters by cholesteryl esterase c. oxidation of cholesterol by cholesterol oxidase d. oxidation of glycerol by glycerol oxidase e. reduction of hydrogen peroxide by peroxidase

The correct answer is: d. oxidation of glycerol by glycerol oxidase

Which statement is false? Enzymatic determination of serum cholesterol and serum triglyceride both involve: Select one: a. hydrolysis of ester bonds b. phosphorylation on the expense of ATP c. oxidation by molecular oxygen d. production of hydrogen peroxide e. oxidation by hydrogen peroxide

The correct answer is: b. phosphorylation on the expense of ATP

Which statement is true? Enzymatic determination of serum triglyceride does but determination of serum cholesterol does not involve: Select one: a. phosphorylation on the expense of ATP b. hydrolysis of ester bonds c. oxidation by molecular oxygen d. dehydrogenation by using NAD+ e. oxidation by hydrogen peroxide

The correct answer is: a. phosphorylation on the expense of ATP

Which statement is true regarding the enzymatic determination of serum lipids? Select one: a. The assay procedure starts with precipitation of chylomicrons by trichloroacetic acid (TCA). b. Lipoprotein lipase is needed to liberate fatty acids and cholesterol from the lipoproteins. c. Both HDL-cholesterol and LDL-cholesterol are directly determined in different serum fractions. d. LDL-cholesterol content is estimated as one fifth of the total serum triglyceride. e. HDL-cholesterol can be determined in blood serum supernatant after precipitation and sedimentation of VLDL and LDL.

The correct answer is: e. HDL-cholesterol can be determined in blood serum supernatant after precipitation and sedimentation of VLDL and LDL.

An uncoupler is: Select one: a. A lipophilic substance or a protein with the ability to transport protons across the inner mitochondrial membrane bypassing the Fo-F1 ATP synthase b. An inhibitor of the Fo-F1 ATP synthase c. An inhibitor of cytochrome c oxidase d. An inhibitor of the adenine nucleotide translocase e. A lipophilic substance or a protein with the ability to transport NADH across the inner mitochondrial membrane

The correct answer is: a. A lipophilic substance or a protein with the ability to transport protons across the inner mitochondrial membrane bypassing the Fo-F1 ATP synthase

Which statement is true regarding serine proteases? Select one: a. Serine proteases are proteases that have serine and tyrosine bonded at the active site. b. The serine proteases are the enzymes that catalyze the hydrolysis of phosphoanhydryl bond. c. The serine proteases are the enzymes that catalyze the hydrolysis of ester or amide bond. d. Serine proteases are proteases that have serine and proline bonded at the active site. e. Hydrolysis of amide bond involves the reaction of acylation of the carbroxyl group of Asp102.

The correct answer is: c. The serine proteases are the enzymes that catalyze the hydrolysis of ester or amide bond.

Which statement is false regarding serine proteases? Select one: a. Serine proteases are proteases that have serine bonded at the active site. b. Serine proteases are the enzymes that catalyze the hydrolysis of ester or amide bond. c. Catalytic triad of serine proteases located in the active site of the enzyme consist of three amino acids: His57, Ser195 and Asp102. d. Many proteases are synthesized and secreted as inactive forms called zymogens and subsequently activated by proteolysis. e. Catalytic triad of serine proteases located in the active site of the enzyme consist of three amino acids: Lys57, Ser195 and Tyr102.

The correct answer is: e. Catalytic triad of serine proteases located in the active site of the enzyme consist of three amino acids: Lys57, Ser195 and Tyr102.

Which statement is true regarding serine proteases? Select one: a. Chymotrypsin is synthesized as active enzyme. b. Substrate binding pocket of chymotrypsin is more hydrophobic than in trypsin, therefore chymotrypsin prefers medium to large sized hydrophobic residues, such as tyrosine, phenylalanine and tryptophan in binding pocket. c. Substrate binding pocket of chymotrypsin is less hydrophobic than in trypsin, therefore chymotrypsin prefers Arg or Lys in binding pocket. d. Chymotrypsin cleave peptide bonds following a negatively charged amino acid serine or histidine. e. Serine proteases are not sequence specific.

The correct answer is: b. Substrate binding pocket of chymotrypsin is more hydrophobic than in trypsin, therefore chymotrypsin prefers medium to large sized hydrophobic residues, such as tyrosine, phenylalanine and tryptophan in binding pocket.

Which statement is false regarding serine proteases? Select one: a. Bound substrate is attacked by acidophilic Asp195 of chymotripsinogen active site forming transition state complex (tetrahedral intermediate). b. Serine proteases responsible for digestion can be categorised based on their substrate specificity as either chymotrypsin-like, trypsin-like or elastase-like. c. Catalysis by serine proteases involves formation of a covalent acyl-enzyme intermediate. d. Trypsin cleaves peptide bonds following a positively charged amino acid lysine or arginine. e. Chymotrypsin is synthesized as inactive proenzymes (chymotrypsinogen) and activated subsequently by proteolysis.

The correct answer is: a. Bound substrate is attacked by acidophilic Asp195 of chymotripsinogen active site forming transition state complex (tetrahedral intermediate).

Which statement is false regarding serine proteases? Select one: a. Chymotrypsin is a digestive enzyme synthesized in its inactive form in the pancreas, along with the related enzymes trypsin and elastase belonging to the superfamily of serine proteases. b. Chymotrypsin is transported to the small intestine in an inactive form. Once the enzyme enters the small intestine, it becomes activated by proteolysis. c. Serine proteases are inhibited by natural inhibitors called "serpins". One of the best-studied serpins are antithrombin and alpha 1-antitrypsin. d. Activation of trypsin is autocatalytic. e. Zymogens are active forms of serine proteases in which active sites are fully saturated by their substrates.

The correct answer is: e. Zymogens are active forms of serine proteases in which active sites are fully saturated by their substrates.

The effect of an uncoupler is: Select one: a. Dissipation of the proton motive force b. Inhibition of respiration c. Increase of mitochondrial ATP synthesis d. Increase in protein transport to mitochondria e. None of them

The correct answer is: a. Dissipation of the proton motive force

2,4-dinitrophenol is: Select one: a. An inhibitor of the Fo-F1 ATP synthase b. An uncoupler c. An inhibitor of cytochrome c oxidase d. An inhibitor of the adenine nucleotide translocase e. None of them

The correct answer is: b. An uncoupler

Atractyloside is: Select one: a. An inhibitor of the adenine nucleotide translocase b. An inhibitor of the Fo-F1 ATP synthase c. An inhibitor of cytochrome c oxidase d. An uncoupler e. None of them

The correct answer is: a. An inhibitor of the adenine nucleotide translocase

Respiratory control ratio is: Select one: a. The ratio of oxygen consumption of mitochondria in the presence of ADP and substrates divided by the oxygen consumption in the absence of ADP or substrates b. The ratio of the amount of NADH transported across the inner mitochondrial membrane divided by the amount of oxygen consumed by mitochondria c. The ratio of the amount of phosphate incorporated to ATP divided by the amount of oxygen consumed by mitochondria d. The ratio of the amount of oxygen consumed by mitochondria divided by moles of H+ translocated across the inner mitochondrial membrane e. None of them

The correct answer is: a. The ratio of oxygen consumption of mitochondria in the presence of ADP and substrates divided by the oxygen consumption in the absence of ADP or substrates

The P/O ratio is: Select one: a. The ratio of oxygen consumption of mitochondria in the presence of ADP and substrates divided by the rate of oxygen consumption in the absence of ADP or substrates b. The ratio of the amount of NADH transported across the inner mitochondrial membrane divided by the amount of oxygen consumed by mitochondria c. The ratio of the amount of phosphate incorporated to ATP divided by the amount of oxygen consumed by mitochondria d. The ratio of the amount of oxygen consumed by mitochondria divided by moles of H+ translocated across the inner mitochondrial membrane e. None of them

The correct answer is: c. The ratio of the amount of phosphate incorporated to ATP divided by the amount of oxygen consumed by mitochondria

Oligomycin is: Select one: a. An inhibitor of the adenine nucleotide translocase b. An uncoupler c. An inhibitor of complex I d. An inhibitor of the Fo-F1 ATP synthase e. An inhibitor of complex IV

The correct answer is: d. An inhibitor of the Fo-F1 ATP synthase

Inhibitors of complex IV are: Select one: a. Rotenone, antimycin b. Oligomycin, atractyloside c. Malonate, 2,4-dinitrophenol d. CN-, CO, N3- e. None of them

The correct answer is: d. CN-, CO, N3-

Mitochondrial succinate dehydrogenase is: Select one: a. an FMN-linked dehydrogenase b. an NADP+-linked dehydrogenase c. an FAD-linked dehydrogenase d. an NAD+-linked dehydrogenase e. a both NAD+ and NADP+-linked dehydrogenase

The correct answer is: c. an FAD-linked dehydrogenase

Which one of the following is a competitive inhibitor of succinate dehydrogenase? Select one: a. rotenone b. malonate c. alanine d. malate e. ATP

The correct answer is: b. malonate

Which one of the following statements describes the mechanism of action of malonate? Select one: a. Acts as an uncoupler b. Acts as inhibitor of ATP/ADP transporter c. Inactivates the ATP synthase complex d. Inactivates pyruvate kinase e. Acts as a competitive inhibitor of succcinate dehydrogenase

The correct answer is: e. Acts as a competitive inhibitor of succcinate dehydrogenase

Which one of the following statements describes the inhibition of succinate dehydrogenase by malonate? Select one: a. malonate decreases Km by interfering with the binding of the substrate b. malonate does not change Km, but decreases Vmax c. malonate can bind to the free E or to the ES complex as well d. malonate does not affect Vmax e. the inhibition by malonate can be enhanced by increasing the concentration of succinate

The correct answer is: d. malonate does not affect Vmax

# Choose the correct answer: The reaction rate of succinate dehydrogenase was measured in the laboratory practice by detecting the following compound: Select one: a. NADH b. oxidized form of iodonitrotetrazolium chloride c. FADH2 d. reduced iodonitrotetrazolium formazan e. amino-4-antipyrine

The correct answer is: d. reduced iodonitrotetrazolium formazan

Which statement is true regarding the inhibiton of succinate dehydrogenase by malonate? Select one: a. malonate binds irreversibly to the active site of the enzyme b. malonate binds reversibly to the active site of the enzyme and therefore not only ES complexes but EI complexes will also be formed c. Km is decreased in the presence of malonate d. vmax is decreased in the presence of malonate e. both the Km and vmax are decreased in the presence of malonate

The correct answer is: b. malonate binds reversibly to the active site of the enzyme and therefore not only ES complexes but EI complexes will also be formed

We characterized the competitive inhibition of succinate dehydrogenase by malonate in the laboratory practice by plotting the results on a graph. Which one of the following statements is true? Select one: a. we plotted malonate concentration versus succinate concentration b. we plotted 1/v versus 1/[S] c. the intercept on the Y axis of the graph gave the -1/KM d. the intercept on the X axis of the graph gave the 1/vmax e. we plotted the reaction rate versus 1/[S]

The correct answer is: b. we plotted 1/v versus 1/[S]

Which one of the following parameters did we use to calculate the rate of the succinate dehydrogenase reaction in the laboratory practice? Select one: a. the concentration of a reduced redox dye b. the concentration of an oxidized redox dye c. the used amount of succinate d. the produced amount of fumarate e. the produced amount of FAD

The correct answer is: a. the concentration of a reduced redox dye

Which one of the following components was not used in the laboratory practice in which succinate dehydrogenase activity was measured? Select one: a. phenolphtalein indicator b. malonate c. FTF (formate-Triton-formaldehyde solution) d. INT (iodonitrotetrazolium chloride) e. mitochondrial membrane

The correct answer is: a. phenolphtalein indicator

The inhibition of succinate dehydrogenase by malonate can be relieved by adding more of the following chemical to the enzyme system: Select one: a. FAD b. succinate c. fumarate d. maleate e. ubiquinone

The correct answer is: b. succinate

Which one of the following statements is false regarding succinate dehydrogenase? Select one: a. the enzyme oxidizes succinate to fumarate b. the enzyme is bound to the inner mitochondrial membrane c. the enzyme contains Fe-S centers and an FAD prosthetic group d. the enzyme is part of the mitochondrial electron transport chain e. the enzyme pumps protons out of the matrix into the intermembrane space

The correct answer is: e. the enzyme pumps protons out of the matrix into the intermembrane space

Which one of the following statements is false? We can use the enzyme kinetic parameters (Km, vmax, kp) determined by Monte Carlo simulation… Select one: a. to identify the rate-limiting step of a metabolic pathway. b. to find the physiologically relevant substrate of a pathway. c. to decide which enzyme is saturated in vivo by its substrate (if in vivo [S] is known). d. to compare the turnover number of two enzymes. e. to calculate the standard Gibb’s free energy value of a reaction.

The correct answer is: e. to calculate the standard Gibb’s free energy value of a reaction.

Regarding the effect of pH and temperature on enzyme activity, which one of the following statements is true? Select one: a. Increasing the temperature will always lead to a decreased rate of the reaction as a result of protein denaturation. b. The changes of pH affect only the enzyme molecules, but not the substrates. c. The effect of temperature on the enzyme molecules is time-independent. d. The frequency of fruitful collisions of the reactant molecules is determined by their kinetic energy and thus by temperature. e. The plot v (reaction rate) versus T (temperature) is a linear ascending curve in the range of 0-90°C in the case of human enzymes.

The correct answer is: d. The frequency of fruitful collisions of the reactant molecules is determined by their kinetic energy and thus by temperature.

Which one of the following Michaelis-Menten assumptions is not correct? Select one: a. the [S] is much larger than the [E] b. the decrease in the [S] is more than 10% of the initial [S] c. the rate of the P → E+S reaction is negligible d. the [ES] is constant e. the increase of the [P] is linear

The correct answer is: b. the decrease in the [S] is more than 10% of the initial [S]

We identified the rate-limiting step of a metabolic pathway in the biochemistry class using computer simulation. How did we predict the flux-generating (rate-limiting) reaction of the S1 metabolic pathway? Select one: a. The in vivo Vmax of this reaction was high, and the in vivo substrate concentration was much greater than the Km. b. The in vivo Vmax of this reaction was low, and the in vivo substrate concentration was much greater than the Km. c. The in vivo Vmax of this reaction was high, and the in vivo substrate concentration was much less than the Km. d. The in vivo Vmax of this reaction was low, and the in vivo substrate concentration was much less than the Km.

The correct answer is: b. The in vivo Vmax of this reaction was low, and the in vivo substrate concentration was much greater than the Km.

Which statement is true regarding the regulation of pyruvate kinase L and M isoenzymes? Select one: a. cAMP dependent phosphorylation increases the affinity of PK-L for the activiting ligands b. Starvation increases the mRNA level of the PK-M isoenzyme. c. The PK-L isoenzyme is allosterically inhibited by ADP. d. Carbohydrate rich diet increases the mRNA level of the PK-M isoenzyme. e. The PK-M isoenzyme shows no allosteric behavior.

The correct answer is: e. The PK-M isoenzyme shows no allosteric behavior.

Which statement is false regarding the regulation of pyruvate kinase L and M isoenzymes? Select one: a. Carbohydrate rich diet increases the PK-L (liver) isoenzyme mRNA level. b. The PK-M (muscle) isoenzyme is allosterically inhibited by ATP or alanine. c. cAMP dependent phosphorylation decreases the affinity of PK-L for the activiting ligands. d. Starvation decreases the mRNA level of the PK-L isoenzyme. e. The PK-L isoenzyme is allosterically activated by fructose-1,6-bisphosphate.

The correct answer is: b. The PK-M (muscle) isoenzyme is allosterically inhibited by ATP or alanine.

Which parameter was measured in the laboratory practice in which we examined the pyruvate kinase (PK) catalyzed reaction? Select one: a. The absorbance changes of NADH, which was synthesized by pyruvate-dehydrogenase in a coupled enzyme reaction. b. The absorbance changes of NADPH, which was produced by hexokinase and glucose-6-phoshate dehydrogenase in a coupled enzyme reaction. c. The absorbance changes of phosphoenol-pyruvate, which was utilized by the PK catalyzed reaction. d. The absorbance changes of NADH, which was consumed by lactate-dehydrogenase in a coupled enzyme reaction. e. The absorbance changes of ATP, which was synthesized by the PK catalyzed reaction.

The correct answer is: d. The absorbance changes of NADH, which was consumed by lactate-dehydrogenase in a coupled enzyme reaction.

The rate of the reaction catalyzed by pyruvate kinase (PK) increases after…. Select one: a. pipetting alanine to the PK-L isoenzyme reaction mix. b. adding fructose-1,6-bisphosphate to the PK-M isoenzyme reaction mix. c. adding fructose-1,6-bisphosphate to the PK-L isoenzyme reaction mix. d. pipetting ATP to the PK-M isoenzyme reaction mix. e. adding alanine to the PK-M reaction mix.

The correct answer is: c. adding fructose-1,6-bisphosphate to the PK-L isoenzyme reaction mix.

The rate of the reaction catalyzed by pyruvate kinase (PK) decreases after… Select one: a. pipetting alanine to the PK-L isoenzyme reaction mix. b. adding fructose-1,6-bisphosphate to the PK-M isoenzyme reaction mix. c. adding fructose-1,6-bisphosphate to the PK-L isoenzyme reaction mix. d. pipetting ATP to the PK-M isoenzyme reaction mix. e. adding alanine to the PK-M isoenzyme reaction mix.

The correct answer is: a. pipetting alanine to the PK-L isoenzyme reaction mix.

Which statement is true regarding the measurement of pyruvate kinase activity in the laboratory practice? Select one: a. the mitochondrial fractions of liver and muscle were used for the experiments b. we demonstrated the activating effect of phosphoenolpyruvate on the PK-M isoenzyme c. the increase in lactate concentration was followed spectrophotometrically d. we demonstrated the activating effect of fructose-2,6-bisphosphate on the PK-L isoenzyme e. the reaction was initiated by the addition of ADP

The correct answer is: e. the reaction was initiated by the addition of ADP

Which statement is false regarding the measurement of pyruvate kinase activity in the laboratory practice? Select one: a. the reaction rate was measured using a coupled enzyme assay b. lactate was oxidized to pyruvate during the experiments c. the reaction mixture contained Mg2+ ions d. ATP was formed during the experiments e. NADH was oxidized during the experiments

The correct answer is: b. lactate was oxidized to pyruvate during the experiments

Which statement is correct? Select one: a. the pancreatic lipase does not need a cofactor for its activity b. the pancreatic lipase is proteolytically activated in the duodenum c. bile acids and co-lipase are necessary for the interfacial activation of pancreatic lipase in the duodenum d. co-lipase is a serine protease, which proteolytically activates pancreatic lipase in the duodenum e. co-lipase alone can emulsify triglycerides in the duodenum

The correct answer is: c. bile acids and co-lipase are necessary for the interfacial activation of pancreatic lipase in the duodenum

How did we measure the enzyme activity of pancreatic lipase in the laboratory practice? Select one: a. free glycerol generation was measured by complexometry b. free fatty acid generation was followed by spectrophotometry c. free fatty acid generation was followed by titration with sodium hydroxide d. free fatty acid generation was followed by titration with HCl e. free glycerol generation was followed by spectrophotometry

The correct answer is: c. free fatty acid generation was followed by titration with sodium hydroxide

Which statement is true for the measurement of pancreatic lipase activity in the laboratory practice? Select one: a. we used olive oil as a substrate b. we used homogenized milk as substrate c. we excluded co-lipase from the reaction mixture d. we compared the activity of pancreatic lipase with that of lipoprotein lipase e. we added apoCII to the reaction mixture

The correct answer is: b. we used homogenized milk as substrate

Which statement is true for the measurement of pancreatic lipase activity in the laboratory practice? Select one: a. we compared pancreatic lipase activities in the absence and presence of milk b. we compared pancreatic lipase activities in the absence and presence of co-lipase c. we compared pancreatic lipase activities in the absence and presence of bile d. we studied the effect of NaOH on the pancreatic lipase activity e. we used formaldehyde in order to activate pancreatic lipase

The correct answer is: c. we compared pancreatic lipase activities in the absence and presence of bile

Which statement is true for the results of our laboratory experiments in which pancreatic lipase activity was measured? Select one: a. we proved that pancreatic lipase is regulated at the level of gene expression b. we found that pancreatic lipase was already active in the pancreas tissue c. we found a higher pancreatic lipase activity in the presence of bile d. our major conclusion was that formaldehyde stops the reaction e. the point of the experiments was to prove that phenolphtalein is pink at acidic pH

The correct answer is: c. we found a higher pancreatic lipase activity in the presence of bile

Which one of the following materials was not used for the laboratory experiment in which pancreatic lipase activity was measured? Select one: a. pancreatic extract b. NaOH c. phenol red indicator d. bile e. 10% formaldehyde solution

The correct answer is: c. phenol red indicator

Which statement is true regarding the laboratory experiment in which pancreatic lipase activity was measured? Select one: a. the triglycerides in the milk were already emulsified b. the bile used for the experiment contained co-lipase as well c. a weak base was used to titrate the liberated fatty acids d. the reaction was started by the addition of bile e. to evaluate the results we plotted the volume of the used bile versus the incubation time

The correct answer is: a. the triglycerides in the milk were already emulsified

Which effect of the bile acids was demonstrated in the laboratory experiment in which pancreatic lipase activity was measured? Select one: a. bile acids emulsify triglycerides in homogenized milk b. bile acids activate pro-co-lipase by proteolysis c. bile acids activate pancreatic lipase by inducing a conformational change d. bile acids activate co-lipase by inducing a conformational change e. bile acids activate pancreatic lipase by proteolysis

The correct answer is: c. bile acids activate pancreatic lipase by inducing a conformational change

Select the correct statements Select one or more: a. The acyl-CoA dehydrogenase is a mitochondrial enzyme b. NAD is the coenzyme of acyl-CoA dehydrogenase c. The acyl-CoA dehydrogenase generates a trans-double bond d. No ketone bodies are produced, if the acyl-CoA dehydrogenase is deficient

The correct answers are: a. The acyl-CoA dehydrogenase is a mitochondrial enzyme, c. The acyl-CoA dehydrogenase generates a trans-double bond, d. No ketone bodies are produced, if the acyl-CoA dehydrogenase is deficient

Select the statements valid for the ketone bodies Select one or more: a. Produced in the liver b. Non-soluble in water c. Only organs expressing the ß-ketoacyl-CoA-transferase enzyme can utilize them d. Their amount increases in parallel with the increase of b-oxidation of fatty acids in the liver e. They are not produced under physiological conditions

The correct answers are: a. Produced in the liver, c. Only organs expressing the ß-ketoacyl-CoA-transferase enzyme can utilize them, d. Their amount increases in parallel with the increase of b-oxidation of fatty acids in the liver

Select the statements valid for the synthesis of fatty acids Select one or more: a. The activity of acetyl-CoA carboxilase primarily determines the overall rate of the process b. The acetyl-CoA is transported in the form of citrate to the site of synthesis c. NADH2 is utilized in the reactions of the process d. The ATP-citrate-lyase provides the immediate precursor of the synthesis e. The carnitine carrier is involved in the process

The correct answers are: a. The activity of acetyl-CoA carboxilase primarily determines the overall rate of the process, b. The acetyl-CoA is transported in the form of citrate to the site of synthesis, d. The ATP-citrate-lyase provides the immediate precursor of the synthesis

Select the statements valid for the synthesis of palmitoic acid Select one or more: a. The fatty acid synthase is a cytoplasmic enzyme b. The elongation of the molecule by two carbon atoms is accompanied by the oxidation of two NADPH c. The fatty acyl-group is attached to ACP in the course of the synthesis d. Malonyl-CoA loses a carboxyl group during the process e. Acetyl CoA binds to a SH-group of the condensing enzyme

The correct answers are: a. The fatty acid synthase is a cytoplasmic enzyme, b. The elongation of the molecule by two carbon atoms is accompanied by the oxidation of two NADPH, c. The fatty acyl-group is attached to ACP in the course of the synthesis, d. Malonyl-CoA loses a carboxyl group during the process, e. Acetyl CoA binds to a SH-group of the condensing enzyme

The amount of which enzymes increases following a carbohydrate-rich meal Select one or more: a. Acetyl-CoA carboxylase b. Fatty acid synthase c. ATP-citrate lyase d. glucose-6-phosphate dehydrogenase e. malic enzyme

The correct answers are: a. Acetyl-CoA carboxylase, b. Fatty acid synthase, c. ATP-citrate lyase, d. glucose-6-phosphate dehydrogenase, e. malic enzyme

Select the statements valid for the synthesis of triacylglycerols (TAG) Select one or more: a. In adipose tissue the glycerol-kinase provides the glycerol-3-phosphate for the TAG synthesis b. One of the intermediates of the synthesis in the liver is the phosphatidate c. One of the intermediates of the synthesis in the intestine is the 2-monoacylglycerol d. The TAG synthesized in the adipose tissue is transported to other tissues by VLDL e. The absorption of TAG in the intestine involves synthesis of TAG in the epithelial cells

The correct answers are: b. One of the intermediates of the synthesis in the liver is the phosphatidate, c. One of the intermediates of the synthesis in the intestine is the 2-monoacylglycerol, e. The absorption of TAG in the intestine involves synthesis of TAG in the epithelial cells

Select the statements valid for the metabolism of fatty acids with odd number of carbon atoms Select one or more: a. Acetyl-CoA is formed in the course of oxidation b. Propionyl-CoA is formed in the course of oxidation c. Biotin is required d. Succinyl-CoA is formed in the course of oxidation e. Vitamin B12 is required

The correct answers are: a. Acetyl-CoA is formed in the course of oxidation, b. Propionyl-CoA is formed in the course of oxidation, c. Biotin is required, d. Succinyl-CoA is formed in the course of oxidation, e. Vitamin B12 is required

Select the coenzymes needed for the b-oxidation of fatty acids Select one or more: a. CoA b. NADP c. FAD d. NAD e. thiamine-PP

The correct answers are: a. CoA, c. FAD, d. NAD

Select the coenzyme needed for both b-oxidation and synthesis of fatty acids Select one: a. Biotin b. CoA c. FAD d. NAD e. NADP

The correct answer is: b. CoA

Select the coenzymes needed for the synthesis of fatty acids Select one or more: a. CoA b. NADP c. FAD d. NAD e. biotin

The correct answers are: a. CoA, b. NADP, e. biotin

Select the compounds, which are not classified as ketone bodies Select one or more: a. Dihydroxyacetone b. Acetoacetate c. b-hydroxybutyrate d. a-hydroxibutyrate e. oxaloacetate

The correct answers are: a. Dihydroxyacetone, d. a-hydroxibutyrate, e. oxaloacetate

The conversion of palmitoyl-CoA (16:0) to myristoyl-CoA (14:0) and 1 mol of acetyl-CoA by the beta-oxidation pathway results in the net formation of: Select one: a. 2 FADH2, 2 NADH, and 1 ATP. b. 2 FADH2 and 2 NADH. c. 1 FADH2, 1 NADH, and 1 ATP. d. 1 FADH2 and 1 NADPH. e. 1 FADH2 and 1 NADH.

The correct answer is: e. 1 FADH2 and 1 NADH.

The following statements are valid for the beta-oxidation of saturated fatty acids with even number of C-atoms: Select one or more: a. localized to the cytosol b. fatty acids must be activated by ketothiolase using ATP c. Malonyl-CoA is an allosteric regulator d. oxidation of 1 mol palmitoic acid to CO2 and water covers the synthesis of 106 mol ATP e. requires vitamin B12 cofactor

The correct answers are: c. Malonyl-CoA is an allosteric regulator, d. oxidation of 1 mol palmitoic acid to CO2 and water covers the synthesis of 106 mol ATP

The rate of fatty acid synthesis is increased by Select one or more: a. insulin b. long-chain fatty acids c. NADH d. glucagon e. citrate

The correct answers are: a. insulin, e. citrate

Which factors participate in intestinal lipid digestion? Select one: a. Lipase and ATP b. Lipase, bile acid and CoA c. Lipoprotein lipase and bile acids d. Mucins and phospholipids e. Pancreatic lipase and bile acids Clear my choice

The correct answer is: e. Pancreatic lipase and bile acids

What is the mechanism of fatty acid activation? Select one: a. a reaction requiring free CoA and ATP b. binding to carnitine c. formation of UDP-acids d. phosphorylation with ATP e. transfer of CoA from malonyl Co

The correct answer is: a. a reaction requiring free CoA and ATP

Which molecule is needed for the transport of fatty acids into the mitochondria? Select one: a. Cardiolipin b. Carnitine c. Carnosine d. Creatine e. Glycine

The correct answer is: b. Carnitine

Which are the enzymes catalyzing the synthesis of fatty acids? Select one or more: a. Acetyl-CoA-carboxylase b. Ketoacyl-reductase c. Malonyl-transacylase d. Acetyl-(acyl) transacylase e. Ketoacyl-synthetase

The correct answers are: a. Acetyl-CoA-carboxylase, b. Ketoacyl-reductase, c. Malonyl-transacylase, d. Acetyl-(acyl) transacylase, e. Ketoacyl-synthetase

Which enzymes participate in the metabolism of ketone bodies? Select one or more: a. ATP-citrate-lyase b. HMG-CoA-lyase c. HMG-CoA -synthase d. HMG-CoA-reductase e. Succinyl-CoA-acetoacetate CoA transferase

The correct answers are: b. HMG-CoA-lyase, c. HMG-CoA -synthase, e. Succinyl-CoA-acetoacetate CoA transferase

Transport of fatty acids from the cytoplasm to the mitochondrial matrix requires: Select one: a. ATP, carnitine, and coenzyme A. b. ATP, carnitine, and pyruvate dehydrogenase. c. ATP, coenzyme A, and hexokinase. d. ATP, coenzyme A, and pyruvate dehydrogenase. e. carnitine, coenzyme A, and hexokinase.

The correct answer is: a. ATP, carnitine, and coenzyme A.

Fatty acids are activated to acyl-CoAs and the acyl group is further transferred to carnitine because: Select one: a. Acyl-carnitines are transported across the mitochondrial membrane, but acyl-CoAs do not. b. acyl-CoAs easily cross the mitochondrial membrane, but the fatty acids themselves will not. c. Carnitine is required to oxidize NAD+ to NADH. d. Fatty acids cannot be oxidized by FAD unless they are in the acyl-carnitine form. e. None of the above is true.

The correct answer is: a. Acyl-carnitines are transported across the mitochondrial membrane, but acyl-CoAs do not.

Carnitine is: Select one: a. a 15-carbon fatty acid. b. an essential cofactor for the citric acid cycle. c. essential for intracellular transport of fatty acids. d. one of the amino acids commonly found in protein. e. present only in carnivorous animals.

The correct answer is: c. essential for intracellular transport of fatty acids.

Which of these is able to cross the inner mitochondrial membrane? Select one: a. acetyl-CoA b. fatty acyl-carnitine c. fatty acyl-CoA d. malonyl-CoA e. None of the above can cross.

The correct answer is: d. malonyl-CoA

Saturated fatty acids are degraded two carbons at a time, producing acetyl-CoA. Under aerobic conditions, how many ATP molecules would be produced per acetyl-CoA formed? Select one: a. 2 b. 3 c. 4 d. 5 e. 6

The correct answer is: c. 4

Which of the following is(are) true of the oxidation of 1 mol of palmitate (a 16-carbon saturated fatty acid; 16:0) by the beta-oxidation pathway, beginning with the free fatty acid in the cytoplasm? Select one or more: a. Activation of the free fatty acid requires the equivalent of two ATPs. b. Inorganic pyrophosphate (PPi) is produced. c. Carnitine functions as an electron acceptor. d. 8 mol of FADH2 are formed. e. 8 mol of acetyl-CoA are formed. f. There is no direct involvement of NAD+.

The correct answers are: a. Activation of the free fatty acid requires the equivalent of two ATPs. b. Inorganic pyrophosphate (PPi) is produced e. 8 mol of acetyl-CoA are formed.

Which of the following statements apply (applies) to the beta-oxidation of fatty acids? Select one or more: a. The process takes place in the cytosol of mammalian cells. b. Carbon atoms are removed from the acyl chain one at a time. c. Before oxidation, fatty acids must be converted to their CoA derivatives. d. NADP+ is the electron acceptor. e. The products of beta-oxidation can directly enter the citric acid cycle for further oxidation.

The correct answers are: c. Before oxidation, fatty acids must be converted to their CoA derivatives. e. The products of beta-oxidation can directly enter the citric acid cycle for further oxidation.

Which of the following is not true regarding the oxidation of 1 mol of palmitate (16:0) by the beta-oxidation pathway? Select one: a. ATP is needed. b. 8 mol of acetyl-CoA are formed. c. AMP and PPi are formed. d. 8 mol of FADH2 are formed. e. The reactions occur in the mitochondria.

The correct answer is: d. 8 mol of FADH2 are formed.

Which compound is an intermediate of the ß-oxidation of fatty acids? Select one: a. CH3--CH2--CO--CH2--OH b. CH3--CH2--CO--CH2--CO--OPO32- c. CH3-- (CH2)20--CO--COOH d. CH3--CH2--CO--CO--S--CoA e. CH3--CO--CH2--CO--S--CoA

The correct answer is: e. CH3--CO--CH2--CO--S--CoA (Acetoacetyl-CoA)

Which of the following statements concerning the ß-oxidation of fatty acids is true? Select one: a. About 1,200 ATP molecules are ultimately produced per 20-carbon fatty acid oxidized. b. The free fatty acid must be carboxylated in the beta position by a biotin-dependent reaction before the process of beta-oxidation commences. c. Two NADH are produced for each acetyl-CoA. d. The free fatty acid must be converted to a thioester before the process of ß-oxidation commences.

The correct answer is: d. The free fatty acid must be converted to a thioester before the process of ß-oxidation commences.

Which of the following is /are true of the ß-oxidation of long-chain fatty acids? Select one or more: a. The enzyme complex that catalyzes the reaction contains biotin. b. FADH2 serves as an electron carrier. c. NADH serves as an electron carrier. d. Oxidation of an 18-carbon fatty acid produces six molecules of propionyl-CoA. e. Oxidation of a 15-carbon fatty acid produces at least one propionyl-CoA.

The correct answers are: b. FADH2 serves as an electron carrier. c. NADH serves as an electron carrier. e. Oxidation of a 15-carbon fatty acid produces at least one propionyl-CoA.

The following fatty acid, in which the indicated carbon is labeled with 14C, is fed to an animal: 14CH3(CH2)9COOHAfter allowing 30 minutes for fatty acid ß-oxidation, the label would most likely be recovered in: Select one: a. acetyl-CoA. b. both acetyl-CoA and propionyl-CoA. c. palmitoyl-CoA. d. propionyl-CoA.

The correct answer is: d. propionyl-CoA.

A fatty acid with an odd number of carbons will enter the citric acid cycle as acetyl-CoA and: Select one: a. butyrate. b. citrate. c. malate. d. succinyl-CoA. e. a-ketoglutarate.

The correct answer is: d. succinyl-CoA.

In the disease sprue, vitamin B12 (cobalamin) is poorly absorbed in the intestine, resulting in vitamin B12 deficiency. If each of the following fatty acids were in the diet, for which one would the process of fatty acid oxidation be most affected in a patient with sprue? Select one: a. CH3(CH2)14COOH b. CH3(CH2)12COOH c. CH3(CH2)11COOH d. CH3(CH2)10COOH

The correct answer is: c. CH3(CH2)11COOH (sum C can't be odd number)

The major site of formation of acetoacetate from fatty acids is the: Select one: a. Adipose tissue. b. Intestinal mucosa. c. Kidney. d. Liver. e. Muscle.

The correct answer is: d. Liver.

Which of the following is not specifically required in the synthesis of fatty acids? Select one: a. acetyl-CoA b. biotin c. HCO3- (CO2) d. malonyl-CoA e. NADH

The correct answer is: e. NADH

Which of the following statements is /are true regarding the synthesis of fatty acids ? Select one: a. Acyl intermediates are thioesters of a low molecular weight protein called acyl carrier protein. b. CO2 or HCO3- is essential. c. The ultimate source of all the carbon atoms in the fatty acid product is acetyl-CoA. d. All of the above are true.

The correct answer is: d. All of the above are true.

Which of the following is not true of the reaction in which malonyl-CoA is produced during fatty acid synthesis? Select one: a. It is stimulated by citrate. b. It requires acyl carrier protein (ACP). c. It requires CO2 (or bicarbonate). d. The cofactor is biotin.

The correct answer is: b. It requires acyl carrier protein (ACP).

If malonyl-CoA is synthesized from radioactive (14C-labeled) carbon dioxide and unlabeled acetyl-CoA, and the labeled malonate is then used for fatty acid synthesis, the final product (fatty acid) will have radioactive carbon in: Select one: a. Every C. b. Every even-numbered C. c. Every odd-numbered C (carboxyl end is C-1). d. No part of the molecule. e. Only the farthest carbon from C-1.

The correct answer is: d. No part of the molecule.

In comparing fatty acid biosynthesis with ß-oxidation of fatty acids, which of the following statements is incorrect? Select one: a. A thioester derivative of crotonic acid (trans-2-butenoic acid) is an intermediate in the synthetic path, but not in the degradative path. b. A thioester derivative of D-ß-hydroxybutyrate is an intermediate in the synthetic path, not in the degradative path. c. Fatty acid biosynthesis uses NADPH exclusively, whereas ß-oxidation uses NAD+ exclusively. d. Fatty acid degradation is catalyzed by cytosolic enzymes; fatty acid synthesis by mitochondrial enzymes. e. The condensation of two moles of acetyl-CoA in the presence of a crude extract is more rapid in bicarbonate buffer than in phosphate buffer at the same pH; the cleavage of acetoacetyl-CoA proceeds equally well in either buffer.

The correct answer is: d. Fatty acid degradation is catalyzed by cytosolic enzymes; fatty acid synthesis by mitochondrial enzymes.

Which of the following is not true of both the fatty acid synthase system and the fatty acid ß-oxidation system? Select one: a. A derivative of the vitamin pantothenic acid is involved. b. Acyl-CoA derivatives are intermediates. c. Double bonds are oxidized or reduced by pyridine nucleotide coenzymes. d. The processes occur in the mitochondrial matrix.

The correct answer is: d. The processes occur in the mitochondrial matrix.

Enzymes that catalyze the synthesis of long chain fatty acids in vertebrate cells: Select one: a. act as seven separate proteins. b. are encoded in mitochondrial genes. c. are localized in the mitochondrial matrix. d. are part of a single polypeptide chain containing several distinct enzyme activities. e. have none of the characteristics above.

The correct answer is: d. are part of a single polypeptide chain containing several distinct enzyme activities.

The rate-limiting step in fatty acid synthesis is: Select one: a. condensation of acetyl-CoA and malonyl-CoA. b. formation of acetyl-CoA from acetate. c. formation of malonyl-CoA from malonate and coenzyme A. d. the reaction catalyzed by acetyl-CoA carboxylase. e. the reduction of the acetoacetyl group to a ß-hydroxybutyryl group

The correct answer is: d. the reaction catalyzed by acetyl-CoA carboxylase.

Which of the following is not true of the fatty acid elongation system of vertebrate cells? Select one: a. It involves the same four-step sequence seen in the fatty acid synthase complex. b. It is located in the smooth endoplasmic reticulum. c. It produces stearoyl-CoA by the extension of palmitoyl-CoA. d. It uses malonyl-CoA as a substrate. e. The immediate precursor of the added carbons is acetyl-CoA.

The correct answer is: e. The immediate precursor of the added carbons is acetyl-CoA.

The enzyme system for adding double bonds to saturated fatty acids requires all of the following except: Select one: a. A mixed-function oxidase. b. ATP. c. Cytochrome b5. d. Molecular oxygen (O2). e. NADPH.

The correct answer is: b. ATP.

Name substituent A that can form phospholipid with Phosphatidic acid. ## Footnote Select one: a. Choline b. Ethanolamine c. Serine d. Myoinositol e. Phosphatidylglycerol

The correct answer is: a. Choline

Name substituent B that can form phospholipid with Phosphatidic acid Select one: a. Ethanolamine b. Choline c. Serine d. Moinositol e. Phosphatidylglycerol

The correct answer is: a. Ethanolamine

Name substituent C that can form phospholipid with Phosphatidic acid. ## Footnote Select one: a. Serine b. Choline c. Ethanolamine d. Myoinositol e. Phosphatidylglycerol

The correct answer is: a. Serine

Name substituent D that can form phospholipid with Phosphatidic acid. ## Footnote Select one: a. Myoinositol b. Choline c. Ethanolamine d. Serine e. Phosphatidylglycerol

The correct answer is: a. Myoinositol

Name substituent E that can form phospholipid with Phosphatidic acid. Select one: a. Phosphatidylglycerol b. Choline c. Ethanolamine d. Serine e. Myoinositol

The correct answer is: a. Phosphatidylglycerol

Name the component of the A sphingomyelin scheme labeled with A. ## Footnote Select one: a. Ceramide b. Sphingosine c. Fatty acid d. Phosphoric acid e. Choline

The correct answer is: a. Ceramide

Name the component on the A sphingomyelin scheme labeled with C. ## Footnote Select one: a. Phosphoric acid b. Ceramide c. Sphingosine d. Fatty acid e. Choline

The correct answer is: d. Fatty acid

Name the molecule on the scheme. ## Footnote Select one: a. Lysophosphatidylcholine (lysolecithin) b. Phosphatidylcholine c. A sphingomyelin d. Plasmalogen e. Galactosylceramide

The correct answer is: a. Lysophosphatidylcholine (lysolecithin)

Name the molecule on the scheme. ## Footnote Select one: a. Plasmalogen b. Phosphatidylcholine c. A sphingomyelin d. Lysophosphatidylcholine (lysolecithin) e. Galactosylceramide

The correct answer is: a. Plasmalogen

Which of the schemes show Plasmalogen? ## Footnote Select one: a. C b. A c. B d. None of them

The correct answer is: a. C

Which of the schemes show A sphingomyelin? ## Footnote Select one: a. A b. B c. C d. None of them

The correct answer is: a. A

Which of the schemes show Lysophosphatidylcholine (lysolecithin)? ## Footnote Select one: a. B b. A c. C d. None of them

The correct answer is: a. B

Which of the schemes show Phosphatidylcholine? ## Footnote Select one: a. None of them b. A c. B d. C

The correct answer is: a. None of them

Name enzyme A on the figure. Select one: a. Acyl-CoA synthetase b. Carnitine palmitoyltransferase I c. Carnitine palmitoyltransferase II d. Carnitine acylcarnitine translocase

The correct answer is: a. Acyl-CoA synthetase

Name enzyme B on the figure. ## Footnote Select one: a. Carnitine palmitoyltransferase I b. Acyl-CoA synthetase c. Carnitine palmitoyltransferase II d. Carnitine acylcarnitine translocase

The correct answer is: a. Carnitine palmitoyltransferase I

Name enzyme C on the figure. ## Footnote Select one: a. Carnitine palmitoyltransferase II b. Acyl-CoA synthetase c. Carnitine palmitoyltransferase I d. Carnitine acylcarnitine translocase

The correct answer is: a. Carnitine palmitoyltransferase II

Name enzyme D on the figure. ## Footnote Select one: a. Carnitine acylcarnitine translocase b. Acyl-CoA synthetase c. Carnitine palmitoyltransferase I d. Carnitine palmitoyltransferase II

The correct answer is: a. Carnitine acylcarnitine translocase

Name the cellular compartment/organelle labeled as A. Select one: a. Cytosol b. Outer mitochondrial membrane c. Intermembrane space d. Inner mitochondrial membrane e. Mitochondrial matrix

The correct answer is: a. Cytosol

Name the cellular compartment/organelle labeled as B ## Footnote Select one: a. Outer mitochondrial membrane b. Cytosol c. Intermembrane space d. Inner mitochondrial membrane e. Mitochondrial matrix

The correct answer is: a. Outer mitochondrial membrane

Name the cellular compartment/organelle labeled as C. ## Footnote Select one: a. Intermembrane space b. Cytosol c. Outer mitochondrial membrane d. Inner mitochondrial membrane e. Mitochondrial matrix

The correct answer is: a. Intermembrane space

Name the cellular compartment/organelle labeled as D ## Footnote Select one: a. Inner mitochondrial membrane b. Mitochondrial matrix c. Cytosol d. Outer mitochondrial membrane e. Intermembrane space

The correct answer is: a. Inner mitochondrial membrane

Name the cellular compartment/organelle labeled as E. ## Footnote Select one: a. Mitochondrial matrix b. Cytosol c. Outer mitochondrial membrane d. Intermembrane space e. Inner mitochondrial membrane

The correct answer is: a. Mitochondrial matrix

The scheme shows one successful step of the β-oxidation of Palmitoyl-CoA. What is the name of the product labeled with A? Select one: a. Acyl-CoA b. Succinyl-CoA c. Acetyl-CoA d. Myristic acid e. Palmitic acid

The correct answer is: a. Acyl-CoA

The scheme shows one successful step of the β-oxidation of Palmitoyl-CoA. What is the name of the product labeled with B? Select one: a. Acetyl-CoA b. Succinyl-CoA c. Myristoyl-CoA

The correct answer is: a. Acetyl-CoA

The scheme shows the β-oxidation of fatty acids. What is the name of the enzyme labeled with A? Select one: a. Acyl-CoA synthetase b. Acyl-CoA dehydrogenase c. Δ2-Enoyl-CoA hydratase d. L(+)-3-hydroxyacyl-CoA dehydrogenase e. Thiolase

The correct answer is: a. Acyl-CoA synthetase

The scheme shows the β-oxidation of fatty acids. What is the name of the enzyme labeled with B? Select one: a. Acyl-CoA dehydrogenase b. Acyl-CoA synthetase c. Δ2-Enoyl-CoA hydratase d. L(+)-3-hydroxyacyl-CoA dehydrogenase e. Thiolase

The correct answer is: a. Acyl-CoA dehydrogenase

The scheme shows the β-oxidation of fatty acids. What is the name of the enzyme labeled with C? Select one: a. Δ2-Enoyl-CoA hydratase b. L(+)-3-hydroxyacyl-CoA dehydrogenase c. Acyl-CoA synthetase d. Acyl-CoA dehydrogenase e. Thiolase

The correct answer is: a. Δ2-Enoyl-CoA hydratase

The scheme shows the β-oxidation of fatty acids. What is the name of the enzyme labeled with E? Select one: a. Thiolase b. Acyl-CoA synthetase c. Acyl-CoA dehydrogenase d. Δ2-Enoyl-CoA hydratase e. L(+)-3-hydroxyacyl-CoA dehydrogenase

The correct answer is: a. Thiolase

oThe scheme shows the β-oxidation of fatty acids. What is the name of the enzyme labeled with D? Select one: a. L(+)-3-hydroxyacyl-CoA dehydrogenase b. Acyl-CoA synthetase c. Acyl-CoA dehydrogenase d. Δ2-Enoyl-CoA hydratase e. Thiolase

The correct answer is: a. L(+)-3-hydroxyacyl-CoA dehydrogenase

Name the displayed intermedier in the oxidation process of Linoleic acid. ## Footnote Select one: a. Linoleyl-CoA b. ∆3-cis-∆6-cis-Dienoyl-CoA c. ∆2-trans-∆6-cis-Dienoyl-CoA d. ∆2-trans-∆4-cis-Dienoyl-CoA e. ∆3-trans-Enoyl-CoA

The correct answer is: a. Linoleyl-CoA

Name the displayed intermedier in the oxidation process of Linoleic acid. ## Footnote Select one: a. ∆3-cis-∆6-cis-Dienoyl-CoA b. ∆2-trans-∆6-cis-Dienoyl-CoA c. ∆2-trans-∆4-cis-Dienoyl-CoA d. ∆3-trans-Enoyl-CoA e. ∆2-trans-Enoyl-CoA

The correct answer is: a. ∆3-cis-∆6-cis-Dienoyl-CoA

Name the displayed intermedier in the oxidation process of Linoleic acid ## Footnote Select one: a. ∆2-trans-∆6-cis-Dienoyl-CoA b. ∆3-cis-∆6-cis-Dienoyl-CoA c. ∆2-trans-∆4-cis-Dienoyl-CoA d. ∆3-trans-Enoyl-CoA e. ∆2-trans-Enoyl-CoA

The correct answer is: a. ∆2-trans-∆6-cis-Dienoyl-CoA

Name the displayed intermedier in the oxidation process of Linoleic acid. ## Footnote Select one: a. ∆2-trans-∆4-cis-Dienoyl-CoA b. ∆3-cis-∆6-cis-Dienoyl-CoA c. ∆2-trans-∆6-cis-Dienoyl-CoA d. ∆3-trans-Enoyl-CoA e. ∆2-trans-Enoyl-CoA

The correct answer is: a. ∆2-trans-∆4-cis-Dienoyl-CoA

Name the displayed intermedier in the oxidation process of Linoleic acid. ## Footnote Select one: a. ∆3-trans-Enoyl-CoA b. ∆2-trans-Enoyl-CoA c. Linoleyl-CoA d. ∆2-trans-∆4-cis-Dienoyl-CoA e. ∆2-trans-∆6-cis-Dienoyl-CoA

The correct answer is: a. ∆3-trans-Enoyl-CoA

Name the displayed intermedier in the oxidation process of Linoleic acid. ## Footnote Select one: a. ∆2-trans-Enoyl-CoA b. ∆2-trans-Dienoyl-CoA c. ∆3-trans-Enoyl-CoA d. ∆3-trans-Dienoyl-CoA e. Linoleyl-CoA

The correct answer is: a. ∆2-trans-Enoyl-CoA

Name the type of the enzyme that catalyzes the shown reaction, part of the oxidation process of Linoleic acid ## Footnote Select one: a. Dehydrogenase b. Reductase c. Isomerase d. None of these

The correct answer is: c. Isomerase

Name the type of the enzyme that catalyzes the shown reaction, part of the oxidation process of Linoleic acid. ## Footnote Select one: a. Isomerase b. Reductase c. Dehydrogenase d. None of these

The correct answer is: a. Isomerase

Name the type of the enzyme that catalyzes the shown reaction, part of the oxidation process of Linoleic acid. ## Footnote Select one: a. Reductase b. Dehydrogenase c. Isomerase d. None of these

The correct answer is: a. Reductase

Name the ketone body labeled with A. ## Footnote Select one: a. Acetoacetate b. Acetone c. D(–)-3-Hydroxybutyrate d. None of these

The correct answer is: a. Acetoacetate

Name the ketone body labeled with B. ## Footnote Select one: a. Acetone b. Acetoacetate c. D(–)-3-Hydroxybutyrate d. None of these

The correct answer is: a. Acetone

Name the ketone body labeled with C. ## Footnote Select one: a. D(–)-3-Hydroxybutyrate b. Acetoacetate c. Acetone d. None of these

The correct answer is: a. D(–)-3-Hydroxybutyrate

Which of the two reactions is/are catalyzed by a mitochondrial enzyme? ## Footnote Select one: a. A b. B c. Both d. None of them

The correct answer is: b. B

Which of the two reactions is/are spontaneous? ## Footnote Select one: a. A b. B c. Both d. None of them

The correct answer is: a. A

Name enzyme A in the chain of ketogenesis. ## Footnote Select one: a. Acyl-CoA synthetase b. Thiolase c. HMG-CoA synthase d. HMG-CoA lyase e. D(–)-3-Hydroxybutyrate dehydrogenase

The correct answer is: a. Acyl-CoA synthetase

Name enzyme B in the chain of ketogenesis. ## Footnote Select one: a. Thiolase b. Acyl-CoA synthetase c. HMG-CoA synthase d. HMG-CoA lyase e. D(–)-3-Hydroxybutyrate dehydrogenase

The correct answer is: a. Thiolase

Name enzyme C in the chain of ketogenesis. ## Footnote Select one: a. HMG-CoA synthase b. Acyl-CoA synthetase c. Thiolase d. HMG-CoA lyase e. D(–)-3-Hydroxybutyrate dehydrogenase

The correct answer is: a. HMG-CoA synthase

Name enzyme D in the chain of ketogenesis. ## Footnote Select one: a. HMG-CoA lyase b. Thiolase c. HMG-CoA synthase d. Acyl-CoA synthetase e. D(–)-3-Hydroxybutyrate dehydrogenase

The correct answer is: a. HMG-CoA lyase

Name enzyme E in the chain of ketogenesis. ## Footnote Select one: a. D(–)-3-Hydroxybutyrate dehydrogenase b. Acyl-CoA synthetase c. Thiolase d. HMG-CoA synthase e. HMG-CoA lyase

The correct answer is: a. D(–)-3-Hydroxybutyrate dehydrogenase

Name molecule A in the chain of ketogenesis. ## Footnote Select one: a. Acetoacetyl-CoA b. Acetyl-CoA c. 3-Hydroxy-3-methylglutaryl-CoA (Hmg-CoA) d. Acetoacetate e. D(–)-3-Hydroxybutyrate

The correct answer is: a. Acetoacetyl-CoA

Name molecule B in the chain of ketogenesis. ## Footnote Select one: a. Acetyl-CoA b. Acetoacetyl-CoA c. 3-Hydroxy-3-methylglutaryl-CoA (Hmg-CoA) d. Acetoacetate e. D(–)-3-Hydroxybutyrate

The correct answer is: a. Acetyl-CoA

Name molecule C in the chain of ketogenesis. ## Footnote Select one: a. 3-Hydroxy-3-methylglutaryl-CoA (Hmg-CoA) b. Acetoacetyl-CoA c. Acetyl-CoA d. Acetoacetate e. D(–)-3-Hydroxybutyrate

The correct answer is: a. 3-Hydroxy-3-methylglutaryl-CoA (Hmg-CoA)

Name molecule D in the chain of ketogenesis. ## Footnote Select one: a. Acetoacetate b. Acetoacetyl-CoA c. Acetyl-CoA d. 3-Hydroxy-3-methylglutaryl-CoA (Hmg-CoA) e. D(–)-3-Hydroxybutyrate

The correct answer is: a. Acetoacetate

Name molecule E in the chain of ketogenesis. ## Footnote Select one: a. D(–)-3-Hydroxybutyrate b. Acetoacetyl-CoA c. Acetyl-CoA d. 3-Hydroxy-3-methylglutaryl-CoA (Hmg-CoA) e. Acetoacetate

The correct answer is: a. D(–)-3-Hydroxybutyrate

Name enzyme A on the figure ## Footnote Select one: a. CoA Transferase b. Thiolase c. Acetyl-CoA carboxylase d. Carnitine palmitoyltransferase-I

The correct answer is: a. CoA Transferase

Name enzyme B on the figure ## Footnote Select one: a. Thiolase b. CoA Transferase c. Acetyl-CoA carboxylase d. Carnitine palmitoyltransferase-I

The correct answer is: a. Thiolase

Name molecule A on the figure ## Footnote Select one: a. Acyl-CoA b. HMG-CoA c. 3-Hydroxybutyrate d. Acetoacetyl-CoA

The correct answer is: a. Acyl-CoA

Name molecule B on the figure. ## Footnote Select one: a. HMG-CoA b. Acyl-CoA c. 3-Hydroxybutyrate d. Acetoacetyl-CoA

The correct answer is: a. HMG-CoA

Name molecule C on the figure. ## Footnote Select one: a. 3-Hydroxybutyrate b. Acetoacetyl-CoA c. Acyl-CoA d. HMG-CoA

The correct answer is: a. 3-Hydroxybutyrate

Name molecule D on the figure. ## Footnote Select one: a. Acetoacetyl-CoA b. Acyl-CoA c. HMG-CoA d. 3-Hydroxybutyrate

The correct answer is: a. Acetoacetyl-CoA

Name molecule A on the figure Select one: a. Acetyl-CoA b. Acetoacetate c. Acetoacetyl-CoA

The correct answer is: a. Acetyl-CoA

Name molecule B on the figure. ## Footnote Select one: a. Acetoacetate b. Acetyl-CoA c. Acetoacetyl-CoA

The correct answer is: a. Acetoacetate

Name molecule C on the figure. ## Footnote Select one: a. Acetoacetyl-CoA b. Acetyl-CoA c. Acetoacetate

The correct answer is: a. Acetoacetyl-CoA

Name enzyme A on the figure. ## Footnote Select one: a. Acetyl-CoA carboxylase b. Carnitine palmitoyltransferase-I c. CoA Transferase d. Thiolase

The correct answer is: a. Acetyl-CoA carboxylase

Name enzyme B on the figure. ## Footnote Select one: a. Carnitine palmitoyltransferase-I b. Acetyl-CoA carboxylase c. CoA Transferase d. Thiolase

The correct answer is: a. Carnitine palmitoyltransferase-I

Name molecule A on the figure. ## Footnote Select one: a. Glucose b. free fatty acids c. very low density lipoprotein

The correct answer is: a. Glucose

Name molecule B on the figure. ## Footnote Select one: a. free fatty acids b. Glucose c. very low density lipoprotein

The correct answer is: a. free fatty acids

Name molecule C on the figure. ## Footnote Select one: a. very low density lipoprotein b. Glucose c. free fatty acids

The correct answer is: a. very low density lipoprotein

Name molecule A on the figure. ## Footnote Select one: a. Acetyl-CoA b. Acyl-CoA c. Malonyl-CoA d. Acylglycerol

The correct answer is: a. Acetyl-CoA

Name molecule B on the figure. ## Footnote Select one: a. Acyl-CoA b. Acetyl-CoA c. Malonyl-CoA d. Acylglycerol

The correct answer is: a. Acyl-CoA

Name molecule C on the figure. ## Footnote Select one: a. Malonyl-CoA b. Acylglycerol c. Acetyl-CoA d. Acyl-CoA

The correct answer is: a. Malonyl-CoA

Name molecule D on the figure ## Footnote Select one: a. Acylglycerol b. Acetyl-CoA c. Acyl-CoA d. Malonyl-CoA

The correct answer is: a. Acylglycerol

What is the name of process A on the scheme? ## Footnote Select one: a. Lipogenesis b. β-Oxidation c. Esterification d. Ketogenesis

The correct answer is: a. Lipogenesis

What is the name of process B on the scheme? ## Footnote Select one: a. β-Oxidation b. Lipogenesis c. Esterification d. Ketogenesis

The correct answer is: a. β-Oxidation

What is the name of process C on the scheme? Select one: a. Esterification b. Ketogenesis c. Lipogenesis d. β-Oxidation

The correct answer is: a. Esterification

What is the name of process D on the scheme? ## Footnote Select one: a. Ketogenesis b. Lipogenesis c. β-Oxidation d. Esterification

The correct answer is: a. Ketogenesis

Name the Enzyme that catalyzes the reaction. Select one: a. Acetyl-CoA carboxylase b. Malonyl/acetyl transacylase c. Ketoacyl synthase d. Ketoacyl reductase e. Thioesterase

The correct answer is: a. Acetyl-CoA carboxylase

Name the Enzyme that catalyzes the reaction. ## Footnote Select one: a. Biotin carboxylase b. Carboxyl transferase c. Malonyl/acetyl transacylase d. Ketoacyl synthase e. Ketoacyl reductase

The correct answer is: a. Biotin carboxylase

Name the Enzyme that catalyzes the reaction. ## Footnote Select one: a. Carboxyl transferase b. Biotin carboxylase c. Malonyl/acetyl transacylase d. Ketoacyl synthase e. Ketoacyl reductase

The correct answer is: a. Carboxyl transferase

What is the correct sequence of enzymes A, B, C, D and E in the primary structure of fatty acid synthase monomer? ## Footnote Select one: a. Ketoacyl synthase, Hydratase, Enoyl reductase, Ketoacyl reductase, Thioesterase b. Ketoacyl reductase, Thioesterase, Enoyl reductase, Ketoacyl synthase, Hydratase c. Ketoacyl synthase, Thioesterase, Hydratase, Enoyl reductase, Ketoacyl reductase d. Ketoacyl reductase, Hydratase, Enoyl reductase, Ketoacyl synthase, Thioesterase e. Ketoacyl reductase, Ketoacyl synthase, Thioesterase, Enoyl reductase, Hydratase

The correct answer is: a. Ketoacyl synthase, Hydratase, Enoyl reductase, Ketoacyl reductase, Thioesterase

What is the correct sequence of enzymes A, B, C, D and E in the primary structure of fatty acid synthase monomer? ## Footnote Select one: a. Malonyl/acetyl transacylase, Hydratase, Enoyl reductase, Ketoacyl reductase, Acyl carrier protein b. Ketoacyl reductase, Acyl carrier protein, Malonyl/acetyl transacylase, Hydratase, Enoyl reductase c. Hydratase, Enoyl reductase, Ketoacyl reductase, Malonyl/acetyl transacylase, Acyl carrier protein d. Enoyl reductase, Ketoacyl reductase, Acyl carrier protein, Hydratase, Malonyl/acetyl transacylase

The correct answer is: a. Malonyl/acetyl transacylase, Hydratase, Enoyl reductase, Ketoacyl reductase, Acyl carrier protein

What is the correct sequence of enzymes A, B, C, D and E in the primary structure of fatty acid synthase monomer? ## Footnote Select one: a. Ketoacyl synthase, Malonyl/acetyl transacylase, Hydratase, Enoyl reductase, Ketoacyl reductase b. Ketoacyl reductase, Enoyl reductase, Hydratase, Malonyl/acetyl transacylase, Ketoacyl synthase c. Ketoacyl synthase, Ketoacyl reductase, Malonyl/acetyl transacylase, Hydratase, Enoyl reductase d. Ketoacyl reductase, Ketoacyl synthase, Enoyl reductase, Hydratase, Malonyl/acetyl transacylase

The correct answer is: a. Ketoacyl synthase, Malonyl/acetyl transacylase, Hydratase, Enoyl reductase, Ketoacyl reductase

What is the correct sequence of enzymes A, B, C, D and E in the primary structure of fatty acid synthase monomer? ## Footnote Select one: a. Hydratase, Enoyl reductase, Ketoacyl reductase, Acyl carrier protein, Thioesterase b. Thioesterase, Enoyl reductase, Ketoacyl reductase, Acyl carrier protein, Hydratase c. Ketoacyl reductase, Acyl carrier protein, Thioesterase, Enoyl reductase, Hydratase d. Enoyl reductase, Ketoacyl reductase, Hydratase, Acyl carrier protein, Thioesterase

The correct answer is: a. Hydratase, Enoyl reductase, Ketoacyl reductase, Acyl carrier protein, Thioesterase

What is the correct sequence of enzymes A, B, C, D and E in the primary structure of fatty acid synthase monomer? ## Footnote Select one: a. Ketoacyl synthase, Enoyl reductase, Ketoacyl reductase, Acyl carrier protein, Thioesterase b. Thioesterase, Enoyl reductase, Ketoacyl reductase, Acyl carrier protein, Ketoacyl synthase c. Ketoacyl reductase, Acyl carrier protein, Thioesterase, Enoyl reductase, Ketoacyl synthase d. Enoyl reductase, Ketoacyl reductase, Ketoacyl synthase, Acyl carrier protein, Thioesterase

The correct answer is: a. Ketoacyl synthase, Enoyl reductase, Ketoacyl reductase, Acyl carrier protein, Thioesterase

What is the correct sequence of enzymes A, B, C, D and E in the primary structure of fatty acid synthase monomer? ## Footnote Select one: a. Ketoacyl synthase, Malonyl/acetyl transacylase, Ketoacyl reductase, Acyl carrier protein, Thioesterase b. Thioesterase, Malonyl/acetyl transacylase, Ketoacyl reductase, Acyl carrier protein, Ketoacyl synthase c. Ketoacyl reductase, Acyl carrier protein, Thioesterase, Malonyl/acetyl transacylase, Ketoacyl synthase d. Malonyl/acetyl transacylase, Ketoacyl reductase, Ketoacyl synthase, Acyl carrier protein, Thioesterase

The correct answer is: a. Ketoacyl synthase, Malonyl/acetyl transacylase, Ketoacyl reductase, Acyl carrier protein, Thioesterase

What is the correct sequence of enzymes A, B, C, D and E in the primary structure of fatty acid synthase monomer? ## Footnote Select one: a. Ketoacyl synthase, Malonyl/acetyl transacylase, Hydratase, Acyl carrier protein, Thioesterase b. Thioesterase, Malonyl/acetyl transacylase, Hydratase, Acyl carrier protein, Ketoacyl synthase c. Hydratase, Acyl carrier protein, Thioesterase, Malonyl/acetyl transacylase, Ketoacyl synthase d. Malonyl/acetyl transacylase, Hydratase, Ketoacyl synthase, Acyl carrier protein, Thioesterase

The correct answer is: a. Ketoacyl synthase, Malonyl/acetyl transacylase, Hydratase, Acyl carrier protein, Thioesterase

What is the correct sequence of enzymes A, B, C, D and E in the primary structure of fatty acid synthase monomer? Select one: a. Ketoacyl synthase, Malonyl/acetyl transacylase, Hydratase, Enoyl reductase, Thioesterase b. Thioesterase, Malonyl/acetyl transacylase, Hydratase, Enoyl reductase, Ketoacyl synthase c. Hydratase, Enoyl reductase, Thioesterase, Malonyl/acetyl transacylase, Ketoacyl synthase d. Malonyl/acetyl transacylase, Hydratase, Ketoacyl synthase, Enoyl reductase, Thioesterase

The correct answer is: a. Ketoacyl synthase, Malonyl/acetyl transacylase, Hydratase, Enoyl reductase, Thioesterase

Name molecule A on the scheme. ## Footnote Select one: a. Acyl(acetyl)-malonyl enzyme b. 3-Ketoacyl enzyme (acetoacetyl enzyme) c. D(–)-3-Hydroxyacyl enzyme d. 2,3-Unsaturated acyl enzyme e. Acyl enzyme

The correct answer is: a. Acyl(acetyl)-malonyl enzyme

Name molecule B on the scheme ## Footnote Select one: a. 3-Ketoacyl enzyme (acetoacetyl enzyme) b. D(–)-3-Hydroxyacyl enzyme c. Acyl enzyme d. 2,3-Unsaturated acyl enzyme e. Acyl(acetyl)-malonyl enzyme

The correct answer is: a. 3-Ketoacyl enzyme (acetoacetyl enzyme)

Name molecule C on the scheme. Select one: a. D(–)-3-Hydroxyacyl enzyme b. 2,3-Unsaturated acyl enzyme c. Acyl enzyme d. Acyl(acetyl)-malonyl enzyme e. 3-Ketoacyl enzyme (acetoacetyl enzyme)

The correct answer is: a. D(–)-3-Hydroxyacyl enzyme

Name molecule D on the scheme. ## Footnote Select one: a. 2,3-Unsaturated acyl enzyme b. Acyl enzyme c. Acyl(acetyl)-malonyl enzyme d. 3-Ketoacyl enzyme (acetoacetyl enzyme) e. D(–)-3-Hydroxyacyl enzyme

The correct answer is: a. 2,3-Unsaturated acyl enzyme

Name molecule E on the scheme. ## Footnote Select one: a. Acyl enzyme b. Acyl(acetyl)-malonyl enzyme c. 3-Ketoacyl enzyme (acetoacetyl enzyme) d. D(–)-3-Hydroxyacyl enzyme e. 2,3-Unsaturated acyl enzyme

The correct answer is: a. Acyl enzyme

Name enzyme A on the scheme. ## Footnote Select one: a. 3-Ketoacyl synthase b. 3-Ketoacyl reductase c. Hydratase d. Enoyl reductase e. Thioesterase

The correct answer is: a. 3-Ketoacyl synthase

Name enzyme B on the scheme. ## Footnote Select one: a. 3-Ketoacyl reductase b. 3-Ketoacyl synthase c. Hydratase d. Enoyl reductase e. Thioesterase

The correct answer is: a. 3-Ketoacyl reductase

Name enzyme C on the scheme. ## Footnote Select one: a. Hydratase b. Enoyl reductase c. Thioesterase d. 3-Ketoacyl synthase e. 3-Ketoacyl reductase

The correct answer is: a. Hydratase

Name enzyme D on the scheme. ## Footnote Select one: a. Enoyl reductase b. Thioesterase c. 3-Ketoacyl synthase d. 3-Ketoacyl reductase e. Hydratase

The correct answer is: a. Enoyl reductase

Name enzyme E on the scheme ## Footnote Select one: a. Thioesterase b. 3-Ketoacyl synthase c. 3-Ketoacyl reductase d. Hydratase e. Enoyl reductase

The correct answer is: a. Thioesterase

Name enzyme A on the scheme. ## Footnote Select one: a. Acetyl-CoA carboxylase b. Malonyl acetyl transacylase c. 3-Ketoacyl synthase d. 3-Ketoacyl reductase

The correct answer is: a. Acetyl-CoA carboxylase

Name enzyme B on the scheme. ## Footnote Select one: a. Malonyl acetyl transacylase b. Acetyl-CoA carboxylase c. 3-Ketoacyl synthase d. 3-Ketoacyl reductase

The correct answer is: a. Malonyl acetyl transacylase

Name enzyme C on the scheme. ## Footnote Select one: a. Malonyl acetyl transacylase b. Acetyl-CoA carboxylase c. 3-Ketoacyl synthase d. 3-Ketoacyl reductase

The correct answer is: a. Malonyl acetyl transacylase

Name molecule A on the scheme. ## Footnote Select one: a. Glucose-6-phosphate b. Fructose-6-phosphate c. Glyceraldehyde-3-phosphate d. Pyruvate

The correct answer is: a. Glucose-6-phosphate

Name molecule B on the scheme Select one: a. Fructose-6-phosphate b. Glucose-6-phosphate c. Glyceraldehyde-3-phosphate d. Pyruvate

The correct answer is: a. Fructose-6-phosphate

Name molecule C on the scheme. ## Footnote Select one: a. Glyceraldehyde-3-phosphate b. Pyruvate c. Glucose-6-phosphate d. Fructose-6-phosphate

The correct answer is: a. Glyceraldehyde-3-phosphate

Name molecule D on the scheme. ## Footnote Select one: a. Pyruvate b. Glucose-6-phosphate c. Fructose-6-phosphate d. Glyceraldehyde-3-phosphate

The correct answer is: a. Pyruvate

Name molecule A on the scheme. ## Footnote Select one: a. Pyruvate b. Malate c. Citrate

The correct answer is: a. Pyruvate

Name molecule B on the scheme. ## Footnote Select one: a. Malate b. Citrate c. Pyruvate

The correct answer is: a. Malate

Name molecule C on the scheme. ## Footnote Select one: a. Citrate b. Pyruvate c. Malate

The correct answer is: a. Citrate

Name enzyme A on the scheme. ## Footnote Select one: a. Malate dehydrogenase b. Malic enzyme c. ATP-citrate lyase d. Pyruvate dehydrogenase e. Isocitrate dehydrogenase

The correct answer is: a. Malate dehydrogenase

Name enzyme B on the scheme. ## Footnote Select one: a. Glyceraldehyde-3-phosphate dehydrogenase b. Malate dehydrogenase c. Pyruvate dehydrogenase d. Acetyl-CoA carboxylase e. Isocitrate dehydrogenase

The correct answer is: a. Glyceraldehyde-3-phosphate dehydrogenase

Name enzyme C on the scheme. ## Footnote Select one: a. Malic enzyme b. Malate dehydrogenase c. ATP-citrate lyase d. Pyruvate dehydrogenase e. Isocitrate dehydrogenase

The correct answer is: a. Malic enzyme

Name enzyme D on the scheme. ## Footnote Select one: a. ATP-citrate lyase b. Pyruvate dehydrogenase c. Acetyl-CoA carboxylase d. Isocitrate dehydrogenase e. Malate dehydrogenase

The correct answer is: a. ATP-citrate lyase

Name enzyme E on the scheme. ## Footnote Select one: a. Pyruvate dehydrogenase b. Acetyl-CoA carboxylase c. Isocitrate dehydrogenase d. Malate dehydrogenase e. ATP-citrate lyase

The correct answer is: a. Pyruvate dehydrogenase

Name enzyme F on the scheme ## Footnote Select one: a. Acetyl-CoA carboxylase b. Isocitrate dehydrogenase c. Pyruvate dehydrogenase d. ATP-citrate lyase e. Malate dehydrogenase

The correct answer is: a. Acetyl-CoA carboxylase

Name enzyme G on the scheme. ## Footnote Select one: a. Isocitrate dehydrogenase b. Isocitrate lyase c. Aconitase d. ATP-citrate lyase e. Malic enzyme

The correct answer is: a. Isocitrate dehydrogenase

Name molecule A on the scheme ## Footnote Select one: a. Citrate b. Isocitrate c. Malate d. Malonyl-CoA

The correct answer is: a. Citrate

Name molecule B on the scheme. ## Footnote Select one: a. Isocitrate b. Citrate c. Malate d. Malonyl-CoA

The correct answer is: a. Isocitrate

Name molecule C on the scheme. ## Footnote Select one: a. Malate b. Malonyl-CoA c. Citrate d. Isocitrate

The correct answer is: a. Malate

Name molecule D on the scheme. ## Footnote Select one: a. Malonyl-CoA b. Malate c. Isocitrate d. Citrate

The correct answer is: a. Malonyl-CoA

Name molecule A on the scheme. ## Footnote Select one: a. Acetyl-CoA b. Oxaloacetate c. α-Ketoglutarate

The correct answer is: a. Acetyl-CoA

Name molecule B on the scheme. ## Footnote Select one: a. Oxaloacetate b. Acetyl-CoA c. α-Ketoglutarate

The correct answer is: a. Oxaloacetate

Name molecule C on the scheme. ## Footnote Select one: a. α-Ketoglutarate b. Oxaloacetate c. Acetyl-CoA

The correct answer is: a. α-Ketoglutarate

Examine the image. Identify "Molecule X". ## Footnote Select one: a. Peripheral apoprotein b. Cholesterol-rich lipid raft c. Transmembrane protein d. Cholesterol-free lipid raft

The correct answer is: a. Peripheral apoprotein

Examine the image. What could be "Molecule X"? ## Footnote Select one: a. Phospholipid b. Transmembrane protein c. Free fatty acid d. Glycerol

The correct answer is: a. Phospholipid

Examine the image. What is "Molecule X"? ## Footnote Select one: a. Cholesteryl ester b. Free cholesterol c. Phosphatidylserine d. Cholesteryl glycerol e. A small hydrophobic protein

The correct answer is: a. Cholesteryl ester

Examine the image. What is "Molecule X"? ## Footnote Select one: a. Triacylglycerol b. Partially degraded cholesterol c. Free fatty acid d. Glycerol e. A short hydrophobic peptide

The correct answer is: a. Triacylglycerol

Examine the image. What is "Molecule X"? ## Footnote Select one: a. Integral apoprotein b. Cholesterol-rich lipid raft c. Cholesterol-free lipid raft d. Caveola

The correct answer is: a. Integral apoprotein

Examine the image. What is "Molecule X"? ## Footnote Select one: a. Free cholesterol b. Small hydrophobic peptide c. Phosphatidylcholine d. Phosphatidylserine

The correct answer is: a. Free cholesterol

Examine the image. Which is true for "Area X"? ## Footnote Select one: a. Lipoprotein core of mainly nonpolar lipids. b. Lipoprotein core of mainly polar lipids. c. Lipoprotein core rich in hydrophobic proteins. d. Lipoprotein core rich in charged lipids.

The correct answer is: a. Lipoprotein core of mainly nonpolar lipids.

Examine the image. Which is true for "Area X"? ## Footnote Select one: a. Monolayer of mainly amphipathic lipids. b. Bilayer of mainly amphipathic lipids. c. Monolayer of mainly nonpolar lipids. d. Bilayer of nolayer of mainly nonpolar lipids.

The correct answer is: a. Monolayer of mainly amphipathic lipids.

Examine the image. What is "Particle X"? ## Footnote Select one: a. Nascent chylomicron b. Chylomicron remnant c. LDL d. HDL

The correct answer is: a. Nascent chylomicron

Examine the image. What is "Particle X"? ## Footnote Select one: a. Chylomicron b. LDL c. HDL d. Chylomicron remnant

The correct answer is: a. Chylomicron

Examine the image. What is "Particle X"? ## Footnote Select one: a. Chylomicron remnant b. LDL c. HDL d. Nascent chylomicron

The correct answer is: a. Chylomicron remnant

Examine the image. What is "Particle X"? ## Footnote Select one: a. HDL b. LDL c. VLDL d. Chylomicron remnant

The correct answer is: a. HDL

Examine the image. What is "Enzyme X", hydrolyzing the chylomicron's triglycerides? ## Footnote Select one: a. Lipoprotein lipase b. Phospholipase C c. Endothelial lipase d. Lysosomal lipase

The correct answer is: a. Lipoprotein lipase

Examine the image. What is "Molecule X"? ## Footnote Select one: a. Glycerol b. Cholesterol c. Triglycerides d. Phospholipids

The correct answer is: a. Glycerol

Examine the image. What is "Molecule X"? ## Footnote Select one: a. Fatty acids b. Cholesterol c. Phospholipids d. Triacylglycerol e. Cholesteryl ester

The correct answer is: a. Fatty acids

Examine the image. What is "Molecule X"? Select one: a. Cholesterol b. Glycerol c. Triacylglycerol d. Phospholipids

The correct answer is: a. Cholesterol

Examine the image. What is "Particle X"? ## Footnote Select one: a. Nascent VLDL b. Intermediate-density lipoprotein (IDL) c. LDL d. HDL

The correct answer is: a. Nascent VLDL

Examine the image. What is "Particle X"? Select one: a. VLDL b. Intermediate-density lipoprotein (IDL) c. LDL d. HDL

The correct answer is: a. VLDL

Examine the image. What is "Particle X"? ## Footnote Select one: a. Intermediate-density lipoprotein (IDL) b. Nascent VLDL c. LDL d. HDL

The correct answer is: a. Intermediate-density lipoprotein (IDL)

Examine the image. What is "Particle X"? ## Footnote Select one: a. LDL b. HDL c. Intermediate-density lipoprotein (IDL) d. VLDL

The correct answer is: a. LDL

Examine the image. What is "Particle X"? Select one: a. HDL b. LDL c. VLDL d. Intermediate-density lipoprotein (IDL)

The correct answer is: a. HDL

Examine the image. What is "Molecule X"? ## Footnote Select one: a. Glucose b. Fructose c. Glucose 1,6-bisphosphate d. Glucose 1-phosphate

The correct answer is: a. Glucose

Examine the image. What is "Hormone X"? ## Footnote Select one: a. Insulin b. Glucagon c. Adrenaline d. Dopamine

The correct answer is: a. Insulin

Examine the image. What is "Molecule X"? ## Footnote Select one: a. Glucose 6-phosphate b. Glucose 1-phosphate c. Glucose 1,6-bisphosphate d. Fructose 6-phosphate

The correct answer is: a. Glucose 6-phosphate

Examine the image. What are "Path X" and "Path Y"? Select one: a. "Path X" is Glycolysis. "Path Y" is Pentose phosphate pathway. b. "Path X" is Pentose phosphate pathway. "Path Y" is Glycolysis. c. Both pathways are alternative versions of Glycolysis. d. "Path X" is Glycolysis. "Path Y" is Gluconeogenesis. e. "Path X" is Glycogenolysis. "Path Y" is Pentose phosphate pathway.

The correct answer is: a. "Path X" is Glycolysis. "Path Y" is Pentose phosphate pathway.

Examine the image. What is "Molecule X"? ## Footnote Select one: a. Acetyl-CoA b. Glycerol c. Fructose d. Cholesterol e. Glucose

The correct answer is: a. Acetyl-CoA

Examine the image. What is "Molecule X"? ## Footnote Select one: a. Glycerol 3-phosphate b. Glucose c. Fructose 1,6-bisphosphate d. Cholesterol e. Dihydroxyacetone phosphate

The correct answer is: a. Glycerol 3-phosphate

Examine the image. What is "Molecule X"? Select one: a. Acyl-CoA b. Acetyl-CoA c. Pyruvate d. Cholesterol e. Glycerol

The correct answer is: a. Acyl-CoA

Examine the image. What is "Enzyme X"? ## Footnote Select one: a. Acyl-CoA synthetase b. Acyl-CoA lyase c. Acyl-CoA reductase d. Phosphoglycerate mutase e. Hexokinase

The correct answer is: a. Acyl-CoA synthetase

Examine the image. What is "Enzyme X"? ## Footnote Select one: a. Hormone-sensitive lipase b. Triacylglycerol reductase c. Glycerol synthetase d. Fatty acid hydrolase

The correct answer is: a. Hormone-sensitive lipase

Examine the image. "Reaction X", combining Acyl-CoA with Glycerol 3-phosphate, is a reaction of... ? ## Footnote Select one: a. Esterification b. Oxidation-reduction c. Etherification d. Hydrolysis

The correct answer is: a. Esterification

Examine the image. "Reaction X", breaking triacylglycerol (TG) into free fatty acids (FFA) and Glycerol, is a reaction of... ? ## Footnote Select one: a. Hydrolysis (Lipolysis) b. Etherification c. Oxidation-reduction d. Transamination e. Dephosphorylation

The correct answer is: a. Hydrolysis (Lipolysis)

Examine the image. What is "Molecule X"? ## Footnote Select one: a. Glycerol b. Acyl-CoA c. Acetyl-CoA d. Cholesterol e. Glycogen

The correct answer is: a. Glycerol

Examine the image. What is "Enzyme X"? ## Footnote Select one: a. Lipoprotein lipase b. Serine hydrolase c. Choline esterase d. Alcohol dehydrogenase e. Triacylglycerol ligase

The correct answer is: a. Lipoprotein lipase

Examine the image and locate the enzyme Hormone-sensitive lipase. Which compounds inhibit this enzyme? ## Footnote Select one: a. Insulin, Nicotinic acid. b. Insulin, Glucagon. c. Glucagon, Epinephrine. d. Insulin, Vasopressin. e. Epinephrine, Nicotinic acid.

The correct answer is: a. Insulin, Nicotinic acid.

Examine the image and locate the enzyme Hormone-sensitive lipase. Which compounds activate this enzyme? Select one: a. Glucagon, Epinephrine. b. Glucagon, Insulin. c. Insulin, Nicotinic acid. d. Glucagon, Nicotinic acid. e. Insulin, Vasopressin.

The correct answer is: a. Glucagon, Epinephrine.

Examine the image. What is "Enzyme X"? ## Footnote Select one: a. Adenylyl cyclase b. ATP-dependent oxidoreductase c. AMP hydrolase d. cAMP kinase

The correct answer is: a. Adenylyl cyclase

Examine the image. What is "Enzyme X"? ## Footnote Select one: a. Phosphodiesterase b. cAMP kinase c. AMP phosphatase d. AMP ligase

The correct answer is: a. Phosphodiesterase

Examine the image. What is "Enzyme X"? ## Footnote Select one: a. Hormone-sensitive lipase b. cAMP-dependent protein phosphatase c. Triacylglycerol kinase d. Triacylglycerol ligase

The correct answer is: a. Hormone-sensitive lipase

Examine the image. What is "Enzyme X"? ## Footnote Select one: a. cAMP-dependent protein kinase b. cAMP-dependent protein phosphatase c. ATP ligase d. cAMP hydrolase

The correct answer is: a. cAMP-dependent protein kinase

Examine the image. What is "Enzyme X"? Select one: a. Lipase phosphatase b. Lipase kinase c. Lipase hydrolase d. cAMP-dependent protein phosphatase e. Lipase oxidoreductase

The correct answer is: a. Lipase phosphatase

Examine the image. What is "Enzyme X"? Select one: a. Hormone-sensitive lipase b. Diacylglycerol ligase c. Monoacylglycerol synthetase

The correct answer is: a. Hormone-sensitive lipase

Examine the image. What is "Enzyme X"? Select one: a. 2-Monoacylglycerol lipase b. 2-Monoacylglycerol kinase c. 2-Monoacylglycerol ligase d. Glycerol synthetase

The correct answer is: a. 2-Monoacylglycerol lipase

Examine the image. What is "Molecule X"? ## Footnote Select one: a. ATP b. ADP c. AMP

The correct answer is: a. ATP

Examine the image. What is "Hormone X", regulating the 3 indicated steps? Select one: a. Insulin b. Glucagon c. Adrenaline (Epinephrine) d. Noradrenaline (Norepinephrine) e. Testosterone

The correct answer is: a. Insulin

Examine the image. Which type of drugs could be "Molecule X"? Select one: a. beta-Adrenergic blockers b. alpha-Adrenergic blockers c. Both alpha- and beta-Adrenergic blockers

The correct answer is: a. beta-Adrenergic blockers

Examine the image. How do the 3 indicated groups of chemical compounds influence the enzyme Adenylyl cyclase? ## Footnote Select one: a. Epinephrine and Glucagon activate the enzyme; Insulin inhibits it. b. Epinephrine and Insulin activate the enzyme; Glucagon inhibits it. c. Nicotinic acid and TSH activate the enzyme; Norepinephrine inhibits it. d. All activate the enzyme. e. All inhibit the enzyme.

The correct answer is: a. Epinephrine and Glucagon activate the enzyme; Insulin inhibits it.

Examine the image. How do Adenosine and FFA (free fatty acids) influence the enzyme Adenylyl cyclase? ## Footnote Select one: a. Both inhibit the enzyme. b. Both activate the enzyme. c. Adenosine activates the enzyme; FFA inhibit it. d. FFA activate the enzyme; Adenosine inhibits it.

The correct answer is: a. Both inhibit the enzyme.

Examine the image. How do the Methylxanthines influence the indicated steps? ## Footnote Select one: a. Inhibition in both cases. b. Activation in both cases. c. Inhibition of Phosphodiesterase; activation of the Adenosine's effect on Adenylyl cyclase. d. Activation of Phosphodiesterase; inhibition of the Adenosine's effect on Adenylyl cyclase.

The correct answer is: a. Inhibition in both cases.

Examine the image. What are the 2 hormones' effects on the indicated steps? ## Footnote Select one: a. Activation in both cases. b. Inhibition in both cases. c. Activation from the Thyroid hormone; inhibition from the Growth hormone. d. Activation from the Growth hormone; inhibition from the Thyroid hormone.

The correct answer is: a. Activation in both cases.

Examine the image. What is the effect of cAMP on the cAMP-dependent protein kinase? Select one: a. Activation. b. Inhibition. c. Neither activation nor inhibition, cAMP is only a substrate for the enzyme.

The correct answer is: a. Activation.

Examine the image. What are the regulatory effects of Insulin and Thyroid hormone on the Phosphodiesterase? ## Footnote Select one: a. Positive from Insulin; negative from Thyroid hormone. b. Positive from Thyroid hormone; negative from Insulin. c. Positive from both. d. Negative from both.

The correct answer is: a. Positive from Insulin; negative from Thyroid hormone.

Examine the image. What are the regulatory effects of Insulin on the indicated steps? ## Footnote Select one: a. Positive on Lipase phosphatase; negative on the cAMP-independent pathway. b. Negative on Lipase phosphatase; positive on the cAMP-independent pathway. c. Positive in both cases. d. Negative in both cases.

The correct answer is: a. Positive on Lipase phosphatase; negative on the cAMP-independent pathway.

Examine the image. What is "Molecule X"? Select one: a. Acetyl-CoA b. Coenzyme A c. Thiocarboxyl-CoA d. Ethanol-CoA

The correct answer is: a. Acetyl-CoA

Examine the image. What is "Molecule X"? ## Footnote Select one: a. Acetoacetyl-CoA b. Butanethiol-CoA c. Glycerol-CoA d. Coenzyme A e. 1-methylpropanol-CoA

The correct answer is: a. Acetoacetyl-CoA

Examine the image. What is "Molecule X"? ## Footnote Select one: a. Coenzyme A b. Acetate c. Acetoacetate d. Formic acid

The correct answer is: a. Coenzyme A

Examine the image. What is "Molecule X"? Select one: a. 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) b. 3-hydroxy-3-methylpentane-CoA c. Acetylglycerol-CoA d. Thiohexane-CoA e. Butane-2-ol-acetyl-CoA

The correct answer is: a. 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA)

Examine the image. What is "Molecule X"? ## Footnote Select one: a. Mevalonate b. 3-hydroxy-3-methylpentanol c. Hydroxymevalonic acid d. Acetyl-acetoacetate

The correct answer is: a. Mevalonate

Examine the image. What is "Enzyme X"? Select one: a. Thiolase b. CoA lyase c. Acetase d. Kinase

The correct answer is: a. Thiolase

Examine the image. What is "Enzyme X"? Select one: a. HMG-CoA synthase b. HMG-CoA lyase c. HMG-CoA hydrolase d. HMG-CoA esterase

The correct answer is: a. HMG-CoA synthase

Examine the image. What is "Enzyme X"? ## Footnote Select one: a. HMG-CoA reductase b. HMG-CoA oxidase c. HMG-CoA lyase d. HMG-CoA hydrolase

The correct answer is: a. HMG-CoA reductase

Examine the image. What is "Molecule X"? ## Footnote Select one: a. Acetyl-CoA b. Coenzyme A c. Acetoacetyl-CoA d. Succinyl-CoA

The correct answer is: a. Acetyl-CoA

Examine the image. What is "Molecule X"? ## Footnote Select one: a. Mevalonate b. Coenzyme A c. 3-methylpentane d. Isoprene

The correct answer is: a. Mevalonate

Examine the image. What is "Molecule X"? ## Footnote Select one: a. Cholesterol b. Stigmasterol c. Progesterone d. Testosterone

The correct answer is: a. Cholesterol

Examine the image. What is "Molecule X"? ## Footnote Select one: a. Chenodeoxycholyl-CoA b. Acetoacetyl-CoA c. Testosteryl-CoA d. Progesteryl-CoA e. Vitamin D

The correct answer is: a. Chenodeoxycholyl-CoA

Examine the image. What is "Molecule X"? ## Footnote Select one: a. Cholyl-CoA b. Acetyl-CoA c. Hydroxycholesterol-CoA d. Cholesteryl-CoA

The correct answer is: a. Cholyl-CoA

Examine the image. What is "Molecule X"? ## Footnote Select one: a. Glycocholic acid b. Cholic acid c. Cholesteryl-glycine

The correct answer is: a. Glycocholic acid

Examine the image. What is "Molecule X"? ## Footnote Select one: a. Deoxycholic acid b. Cholic acid c. Vitamin D

The correct answer is: a. Deoxycholic acid

Examine the image. What is "Molecule X"? Select one: a. Lithocholic acid b. Cholic acid c. Vitamin D d. Chenodeoxycholic acid

The correct answer is: a. Lithocholic acid

Examine the image. What is "Enzyme X"? ## Footnote Select one: a. Hydroxylase b. Oxidase c. Lyase d. Ligase

The correct answer is: a. Hydroxylase

Examine the image. What is "Enzyme X"? Select one: a. Hydroxylase b. Oxidase c. Lyase d. Ligase

The correct answer is: a. Hydroxylase

You can see the elongation of fatty acid chains below. Where do these reactions occur? ## Footnote Select one: a. Mitochondria b. Cytosol c. Nucleus d. Endoplasmic reticulum

The correct answer is: d. Endoplasmic reticulum

You can see the microsomal fatty acid elongase system below. Which substrate (S) fits in the figure? Select one: a. Acetyl-CoA b. Malonyl-CoA c. Propionyl-CoA d. Butyryl-CoA

The correct answer is: b. Malonyl-CoA

You can see the microsomal fatty acid elongase system below. Which substrate (S) fits in the figure? Select one: a. Acetyl-CoA b. Acyl-CoA c. Propionyl-CoA d. Butyryl-CoA

The correct answer is: b. Acyl-CoA

You can see the elongation of fatty acid chains below. Identify the first enzyme (E1) of the elongase system. ## Footnote Select one: a. 3-Ketoacyl-CoA synthase b. 3-Ketoacyl-CoA reductase c. Malonyl-CoA decarboxylase d. Malonyl-CoA reductase

The correct answer is: a. 3-Ketoacyl-CoA synthase

You can see the elongation of fatty acid chains below. Identify the second enzyme (E2) of the elongase system. ## Footnote Select one: a. 3-Ketoacyl-CoA reductase b. 3-Ketoacyl-CoA oxidase c. 3-Hydroxyacyl-CoA synthase d. 3-Ketoacyl-CoA decarboxylas

The correct answer is: a. 3-Ketoacyl-CoA reductase

You can see the elongation of fatty acid chains below. Identify the third enzyme (E3) of the elongase system ## Footnote Select one: a. 3-Hydroxyacyl-CoA reductase b. 3-Hydroxyacyl-CoA oxidase c. 3-Hydroxyacyl-CoA dehydrase d. 2-trans-Enoyl-CoA synthase

The correct answer is: c. 3-Hydroxyacyl-CoA dehydrase

You can see the elongation of fatty acid chains below. Identify the forth enzyme (E4) of the elongase system. ## Footnote Select one: a. 2-trans-Enoyl-CoA dehydrogenase b. 2-trans-Enoyl-CoA decarboxylase c. 2-trans-Enoyl-CoA oxidase d. 2-trans-Enoyl-CoA reductase

The correct answer is: d. 2-trans-Enoyl-CoA reductase

You can see the elongation of fatty acids. Identify the cofactor (C) used in the following reactions: ## Footnote Select one: a. NADH + H+ b. NAD+ c. NADPH + H+ d. NADP+ e. Both NADPH + H+ and NADH + H+ can be used f. Both NADP+ and NAD+ can be used

The correct answer is: e. Both NADPH + H+ and NADH + H+ can be used

In the picture you can see the regulation of an enzyme. Which enzyme is it? Select one: a. Acetyl-CoA carboxylase b. Acetyl-CoA dehydrogenase c. Malonyl-CoA decarboxylase d. Fatty acid synthase

The correct answer is: a. Acetyl-CoA carboxylase

In the picture you can see the regulatory method of an enzyme which catalyses the first step of lipogenesis. Identify the substrate of this enzyme. Select one: a. Acetyl-CoA b. Citrate c. Propionyl-CoA d. Oxaloacetate

The correct answer is: a. Acetyl-CoA

What product (P) is formed in the reaction catalyzed by Acetyl-CoA carboxylase? ## Footnote Select one: a. Malonyl-CoA b. Propionyl-CoA c. Citrate d. Acetyl-carnitine

The correct answer is: a. Malonyl-CoA

In the picture you can see the regulation of the Acetyl-CoA carboxylase. Identify the missing H1 hormone. ## Footnote Select one: a. Glucagon b. Insulin c. Adrenalin d. Growth hormone

The correct answer is: b. Insulin

Which molecule (L) fits in the figure? ## Footnote Select one: a. Acyl-CoA b. Propionyl-CoA c. Ketoacyl-CoA d. Hydroacyl-CoA

The correct answer is: a. Acyl-CoA

Where does the following reaction occur? ## Footnote Select one: a. Mitochondria b. Cytosol c. Nucleus d. Endoplasmic reticulum

The correct answer is: d. Endoplasmic reticulum

Which substrate would you choose for the following reaction? Select one: a. Stearoyl-CoA b. Palmitoyl-CoA c. Palmitoleoyl-CoA d. Enoyl-CoA

The correct answer is: a. Stearoyl-CoA

What product (P) is formed in the following reaction? ## Footnote Select one: a. Oleoyl-CoA b. Palmitoleoyl-CoA c. Enoyl-CoA d. Palmitoyl-CoA

The correct answer is: a. Oleoyl-CoA

# Choose the missing enzym. Select one: a. Δ9 desaturase b. Δ4 desaturase c. Δ5 desaturase d. Δ6 desaturase

The correct answer is: a. Δ9 desaturase

Identify the cofactor (C) used in the following reaction. ## Footnote Select one: a. NADH + H+ b. NAD+ c. NADPH + H+ d. NADP+

The correct answer is: a. NADH + H+

In the picture you can see the synthesis of both prostacyclins and thromboxanes. Identify the localization of prostacyclin synthesis. ## Footnote Select one: a. Platelets b. Blood vessel walls c. Red blood cells d. Leukocytes

The correct answer is: b. Blood vessel walls

In the picture you can see the synthesis of both prostacyclins and thromboxanes. Identify the localization of thromboxane synthesis. ## Footnote Select one: a. Platelets b. Blood vessel walls c. Red blood cells d. Leukocytes

The correct answer is: a. Platelets

What substrate (S) is used by Cyclooxygenase enzyme in the following reaction? ## Footnote Select one: a. Arachidonic acid b. Lignoceric acid c. Behenic acid d. Stearic acid

The correct answer is: a. Arachidonic acid

Identify the enzyme (E) that catalyses the conversion of Arachidonate to PGG2. ## Footnote Select one: a. Cyclooxygenase b. Peroxidase c. Lipoxygenase d. Dehydrogenase

The correct answer is: a. Cyclooxygenase

What product (P) is formed by Thromboxane synthase enzyme in the reaction below? ## Footnote Select one: a. TXA2 b. TXB2 c. TXC2 d. TXD2

The correct answer is: a. TXA2

What product (P) is formed in the last step of thromboxane synthesis? Select one: a. TXA2 b. TXB2 c. TXC2 d. TXD2

The correct answer is: b. TXB2

Which enzyme (E) fits in the figure? ## Footnote Select one: a. Thromboxane synthase b. Dehydrogenase c. Reductase d. Epimerase

The correct answer is: a. Thromboxane synthase

Which enzyme (E) fits in the figure? ## Footnote Select one: a. Prostacyclin synthase b. Lipoxigenase c. Dehydrogenase

The correct answer is: a. Prostacyclin synthase

Which drug can be used to inhibit the Cyclooxygenase enzyme? ## Footnote Select one: a. Aspirin b. Acyclovir c. Ezetimibe d. Lovastatin

The correct answer is: a. Aspirin

In the picture you can see a synthetic pathway.Identify the molecules synthetized by this pathway ## Footnote Select one: a. Leukotrienes b. Lipoxins c. Prostaglandins d. Thromboxanes

The correct answer is: a. Leukotrienes

In the picture you can see a synthetic pathway. Identify the molecules synthetized by this pathway. ## Footnote Select one: a. Leukotrienes b. Lipoxins c. Prostaglandins d. Thromboxanes

The correct answer is: b. Lipoxins

In the picture you can see the synthesis of leukotrienes and lipoxins. What is the starting material of this synthetic pathway? Select one: a. Arachidonic acid b. Lignoceric acid c. Behenic acid d. Stearic acid

The correct answer is: a. Arachidonic acid

In the picture you can see the synthesis of leukotrienes and lipoxins. Which cell type does the leukotriene synthesis occur in? ## Footnote Select one: a. Red blood cells b. Leukocytes c. Endothelial cells

The correct answer is: b. Leukocytes

In the picture you can see the synthesis of leukotrienes and lipoxins. Which cell type does the lipoxin synthesis occur in? ## Footnote Select one: a. Red blood cells b. Leukocytes c. Endothelial cells

The correct answer is: b. Leukocytes

In the picture you can see the synthesis of leukotrienes and lipoxins. Identify the first synthetized leukotriene (A) ## Footnote Select one: a. Leukotriene A4 b. Leukotriene C4 c. Leukotriene D4 d. Leukotriene E4

The correct answer is: a. Leukotriene A4

In the picture you can see the synthesis of leukotrienes and lipoxins. Identify the leukotriene marked with A. ## Footnote Select one: a. Leukotriene B4 b. Leukotriene C4 c. Leukotriene D4 d. Leukotriene E4

The correct answer is: a. Leukotriene B4

n the picture you can see the synthesis of leukotrienes and lipoxins. Identify the leukotriene marked with A. ## Footnote Select one: a. Leukotriene B4 b. Leukotriene C4 c. Leukotriene D4 d. Leukotriene E4

The correct answer is: d. Leukotriene E4

The correct answer is: b. Leukotriene C4

The correct answer is: c. Leukotriene D4

In the picture you can see the synthesis of leukotrienes and lipoxins. Identify the molecule marked with A. ## Footnote Select one: a. Leukotriene B4 b. Leukotriene C4 c. Leukotriene D4 d. Lipoxin

The correct answer is: d. Lipoxin

Which tissue does NOT have Glycerol kinase enzyme? ## Footnote Select one: a. White adipose tissue b. Liver c. Kidney d. Lactating mammary gland

The correct answer is: a. White adipose tissue (found in BROWN adipose tissue)

Which tissue has Glycerol kinase enzyme? Select one: a. Kidney b. Liver c. Intestine d. All of them

The correct answer is: d. All of them

Which enzyme (E) is missing from the figure? Select one: a. Glycerol kinase b. Glycerol carboxylase c. Glycerol dehydrogenase d. Glycerol dehydratase

The correct answer is: a. Glycerol kinase

Which enzyme (E) is missing from the figure? ## Footnote Select one: a. Glycerol-3-phosphate kinase b. Glycerol-3-phosphate carboxylase c. Glycerol-3-phosphate dehydrogenase d. Glycerol-3-phosphate dehydratase

The correct answer is: c. Glycerol-3-phosphate dehydrogenase

What product (P) is formed in the reaction shown below? ## Footnote Select one: a. Dihydroxyacetone phosphate b. Dihydroxyacetone c. Glyceraldehyde d. Glyceraldehyde-3-phosphate

The correct answer is: a. Dihydroxyacetone phosphate

What compound is used by Glycerol kinase in the following reaction? ## Footnote Select one: a. ATP b. NADH + H+ c. NADPH + H+ d. FAD

The correct answer is: a. ATP

What cofactor is used by Glycerol-3-phosphate dehydrogenase in the following reaction? Select one: a. ATP b. NADH + H+ c. NADPH + H+ d. NAD+ e. NADP+

The correct answer is: d. NAD+

In the picture you can see the synthesis of Phosphatidylcholine. Where do these reactions occur? ## Footnote Select one: a. Liver b. Bowel c. Adipose tissue d. All of them

The correct answer is: d. All of them

In the picture you can see the synthesis of Phosphatidylcholine. Identify the first enzyme (E) of this synthetic pathway. ## Footnote Select one: a. Cholin carboxylase b. Cholin decarboxylase c. Cholin kinase

The correct answer is: c. Cholin kinase

In the picture you can see the synthesis of Phosphatidylcholine. Identify the second enzyme (E) of this synthetic pathway. ## Footnote Select one: a. CTP:phosphocholine cytidyl transferase b. Glucuronyltransferase c. Phosphocholine phosphatase d. CTP:phosphocholine cholin transferase

The correct answer is: a. CTP:phosphocholine cytidyl transferase

In the picture you can see the synthesis of Phosphatidylcholine. Identify the third enzyme (E) of this synthetic pathway. ## Footnote Select one: a. CDP-choline:diacylglycerol phosphocholine transferase b. Glucuronyltransferase c. CDP-choline:phosphocholine acyltransferase d. CDP-choline:diacylglycerol choline transferase

The correct answer is: a. CDP-choline:diacylglycerol phosphocholine transferase

In the picture you can see a synthetic pathway. Identify the product (P) synthetized by this pathway. ## Footnote Select one: a. Phosphatidylcholine b. Phosphatidylserine c. Phosphatidylinositol d. Triacylglycerol

The correct answer is: a. Phosphatidylcholine

Which enzyme (E) is missing from the figure? ## Footnote Select one: a. Phosphatidylinositol synthase b. Inositol transferase c. Cytidine transferase d. CDP-diacylglycerol:inositol acyltransferase

The correct answer is: a. Phosphatidylinositol synthase

What specialized function do inositol phospholipids have? Select one: a. Act as precursors of hormone second messengers b. Neurotransmitters c. Cell adhesion molecules on cell surfaces d. ABO blood group substances

The correct answer is: a. Act as precursors of hormone second messengers

Identify the substrate (S) of the reaction shown below. ## Footnote Select one: a. CDP-diacylglycerol b. CTP-diacylglycerol c. CMP-diacylglycerol d. UDP-diacylglycerol

The correct answer is: a. CDP-diacylglycerol

Where does the Phosphatidylethanolamine-Phosphatidylcholine transformation occur? ## Footnote Select one: a. Liver b. Kidney c. Adipose tissue d. All of them

The correct answer is: a. Liver

What product (P) is formed by Phosphatidylethanolamine N-methyltranferase in the following reaction? Select one: a. Phosphatidylinositol b. Phosphatidylcholine c. Phosphatidylinositol 3-phosphate d. Ethanolamine

The correct answer is: b. Phosphatidylcholine

Identify the missing enzyme (E). Select one: a. Phosphatidylethanolamine N-methyltranferase b. Phosphatidylethanolamine carboxylase c. Phosphatidylcholine synthase

The correct answer is: a. Phosphatidylethanolamine N-methyltranferase

Which enzyme (E) would you complete the figure with? Select one: a. Phosphatidate phosphohydrolase b. Phosphatidate phosphorylase c. Phosphatidate cytidylyltransferase d. 1,2-Diacylglycerol synthase

The correct answer is: a. Phosphatidate phosphohydrolase

Which enzyme (E) would you complete the figure with? ## Footnote Select one: a. Diacylglycerol acyltransferase b. Diacylglycerol kinase c. Triacylglycerol synthase

The correct answer is: a. Diacylglycerol acyltransferase

Identify Compound A in the reaction shown below. ## Footnote Select one: a. Acyl-CoA b. Acetyl-CoA c. Malonyl-Coa d. 3-Monoacylglycerol

The correct answer is: a. Acyl-CoA

What product is formed in the following reaction? Select one: a. Triacylglycerol b. 2,3-Diacylglycerol c. 1,3-Diacylglycerol d. 2-Monoacylglycerol

The correct answer is: a. Triacylglycerol

What product can be synthetized directly from Phosphatidylinositol? ## Footnote Select one: a. Phosphatidylinositol 4-phosphate b. Phosphatidylinositol 4,5-bisphosphate c. Phosphatidylinositol 3,4-bisphosphate d. Phosphatidylinositol 3,5-bisphosphate

The correct answer is: a. Phosphatidylinositol 4-phosphate

In the picture you can see the synthesis of plasmalogen and platelet activating factor (PAF). Identify the precursor of this synthetic pathway. Select one: a. Dihydroxyacetone phosphate b. Glycerol 3-phosphate c. Glyceraldehyde 3-phosphate

The correct answer is: a. Dihydroxyacetone phosphate

In the picture you can see the conversion of Phosphatidylcholine to Lysolecithin. Which enzyme can also form Lysolecithin in an alternative route? ## Footnote Select one: a. LCAT b. ACAT c. Both of them

The correct answer is: a. LCAT

Identify Compound A. ## Footnote Select one: a. Phosphatidylcholine b. Phosphatidylethanolamine c. Plasmalogen d. Platelet activating factor

The correct answer is: a. Phosphatidylcholine

Identify the end-product (P) of Phosphatidylcholine metabolism. Select one: a. Dihydroxyacetone phosphate b. Glycerol 3-phosphate c. Glyceraldehyde 3-phosphate

The correct answer is: b. Glycerol 3-phosphate

Identify the missing enzyme (E). ## Footnote Select one: a. Phospholipase A2 b. Phospholipase A1 c. Phospholipase B d. Phospholipase C e. Phospholipase D

The correct answer is: a. Phospholipase A2

Identify Phospholipase 1 (PL1). ## Footnote Select one: a. Phospholipase A2 b. Phospholipase A1 c. Phospholipase B d. Phospholipase C e. Phospholipase D

The correct answer is: c. Phospholipase B

Identify Phospholipase 2 (PL2). ## Footnote Select one: a. Phospholipase A2 b. Phospholipase A1 c. Phospholipase B d. Phospholipase C e. Phospholipase D

The correct answer is: b. Phospholipase A1

Identify Phospholipase 3 (PL3). ## Footnote Select one: a. Phospholipase A2 b. Phospholipase A1 c. Phospholipase B d. Phospholipase C e. Phospholipase D

The correct answer is: e. Phospholipase D

Identify Phospholipase 4 (PL4). ## Footnote Select one: a. Phospholipase A2 b. Phospholipase A1 c. Phospholipase B d. Phospholipase C e. Phospholipase D

The correct answer is: d. Phospholipase C

Identify Phospholipase 5 (PL5). ## Footnote Select one: a. Phospholipase A2 b. Phospholipase A1 c. Phospholipase B d. Phospholipase C e. Phospholipase D

The correct answer is: a. Phospholipase A2

In the picture you can see the synthesis of ceramide. Identify the missing starting material (SM1). ## Footnote Select one: a. Palmitoyl-CoA b. Palmitic acid c. Palmitoylethanolamide d. Palmitoyl Oligopeptide

The correct answer is: a. Palmitoyl-CoA

In the picture you can see the synthesis of ceramide. Identify the missing starting material (SM2). Select one: a. Serine b. Threonine c. Asparagine d. Glutamine

The correct answer is: a. Serine

In the picture you can see the synthesis of ceramide. Identify the missing starting materials (SM1 and SM2). ## Footnote Select one: a. Palmitoyl-CoA and Serine b. Palmitoyl-CoA and Threonine c. Stearoyl-CoA and Serine d. Stearoyl-CoA and Threonine

The correct answer is: a. Palmitoyl-CoA and Serine

In the picture you can see the synthesis of ceramide. Identify the missing enzyme (E). Select one: a. Serine palmitoyltransferase b. Serine stearoyltransferase c. 3-Ketosphinganine synthase

The correct answer is: a. Serine palmitoyltransferase

In the picture you can see a synthetic pathway. What product (P) is formed in this pathway? ## Footnote Select one: a. Ceramide b. Galactosylceramide (cerebroside) c. Sulfogalactosylceramide (sulfatide) d. Sphingomyelin

The correct answer is: a. Ceramide

Where does the following reaction mainly occur? Select one: a. Golgi apparatus b. Mitochondria c. Peroxisome d. Endoplasmic reticulum

The correct answer is: a. Golgi apparatus

What substrate (S) is used in the synthesis of Sphingomyelin? Select one: a. Ceramide b. Galactosylceramide (cerebroside) c. Sulfogalactosylceramide (sulfatide) d. Glucosylceramide

The correct answer is: a. Ceramide

What product (P) is formed in the reaction shown below? ## Footnote Select one: a. Sphingomyelin b. Galactosylceramide (cerebroside) c. Sulfogalactosylceramide (sulfatide) d. Glucosylceramide

The correct answer is: a. Sphingomyelin

Identify Compound A in the following reaction. ## Footnote Select one: a. Phosphatidylcholine b. Phosphatidylethanolamine c. Phosphatidylserine

The correct answer is: a. Phosphatidylcholine

Identify the missing substrate (S). ## Footnote Select one: a. Ceramide b. Glucosylceramide c. Sphingomyelin

The correct answer is: a. Ceramide

Identify the missing compound (C). ## Footnote Select one: a. UDPGal b. GDPGal c. GDPGlc d. UDPGlc

The correct answer is: a. UDPGal

Identify the missing compound (C). ## Footnote Select one: a. PAPS b. Sulfate ion c. Ammonium persulfate

The correct answer is: a. PAPS

Glucosylceramide is a Glycosphingolipid. Which statement is FALSE concerning these compounds? ## Footnote Select one: a. They are constituents of the outer leaflet of plasma membranes. b. They are important in cell adhesion. c. Some are antigens, for example, ABO blood group substances. d. They can be neurotransmitters.

The correct answer is: d. They can be neurotransmitters.

Identify the missing substrate (S). ## Footnote Select one: a. Ceramide b. Galactosylceramide c. Sphingomyelin

The correct answer is: a. Ceramide

Identify the missing compound (C). ## Footnote Select one: a. UDPGlc b. GDPGal c. GDPGlc d. UDPGal

The correct answer is: a. UDPGlc

Identify the product (P) of the reaction shown below. ## Footnote Select one: a. Glucosylceramide b. Galactosylceramide c. Sphingomyelin d. Sulfogalactosylceramide

The correct answer is: a. Glucosylceramide

What type of compound is the product of this reaction? ## Footnote Select one: a. Ganglioside b. Cerebroside c. Globoside

The correct answer is: a. Ganglioside

The curve indicated by A shows? ## Footnote Select one: a. Plasma insulin concentration b. Plasma glucagon concentration c. Liver glycogen concentration d. Blood glucose concentration

The correct answer is: b. Plasma glucagon concentration

The curve indicated by F shows? ## Footnote Select one: a. Plasma insulin concentration b. Blood ketone bodies concentration c. Liver glycogen concentration d. Blood glucose concentration

The correct answer is: b. Blood ketone bodies concentration

If B is blood glucose level, then the curve indicated by G shows? ## Footnote Select one: a. Plasma insulin concentration b. Blood ketone bodies concentration c. Liver glycogen concentration d. Plasma glucagon concentration

The correct answer is: a. Plasma insulin concentration

The curve indicated by E shows? ## Footnote Select one: a. Plasma insulin concentration b. Blood ketone bodies concentration c. Liver glycogen concentration d. Plasma glucagon concentration

The correct answer is: c, Liver glycogen concentration

If G is plasma insulin concentration, then the curve indicated by B shows? ## Footnote Select one: a. Blood glucose concentration b. Blood ketone bodies concentration c. Liver glycogen concentration d. Plasma glucagon concentration

The correct answer is: a. Blood glucose concentration

What is the role of nucleotides? Select one or more: a. Hydrolysis of PP bound to ATP to drive reactions that require an input of energy b. Building blocks of DNA and RNA c. Component of coenzymes d. Second messengers e. Allosteric effectors of metabolic processes

The correct answers are: a. Hydrolysis of PP bound to ATP to drive reactions that require an input of energy, b. Building blocks of DNA and RNA, c. Component of coenzymes, d. Second messengers, e. Allosteric effectors of metabolic processes

Which of the following statements are valid, if hypoxanthine-guanine phosphoribosyl transferase is deficient? Select one or more: a. Hypoxanthine is not converted to IMP b. Hypoxanthine is converted to CMP c. Guanine is not converted to GMP d. De novo purine nucleotide synthesis is enhanced e. Hyperuricaemia develops

The correct answers are: a. Hypoxanthine is not converted to IMP, c. Guanine is not converted to GMP, d. De novo purine nucleotide synthesis is enhanced, e. Hyperuricaemia develops

Which of the following statements are valid for the salvage reactions of purine and pyrimidine nucleotides? Select one or more: a. Mononucleotides are formed from free bases by phosphoribosylation b. De novo nucleotide synthesis is inhibited c. Purine and pyrimidine bases are utilized d. PRPP is required for the salvage reactions e. Ribonucleosides are phosphorylated using ATP

The correct answers are: a. Mononucleotides are formed from free bases by phosphoribosylation, b. De novo nucleotide synthesis is inhibited, c. Purine and pyrimidine bases are utilized, d. PRPP is required for the salvage reactions, e. Ribonucleosides are phosphorylated using ATP

Which of the following states result in hyperuricaemia? Select one or more: a. Deficiency of glucose-6-phosphatase b. Deficiency of hypoxanthine-guanine-phosphoribosyl transferase c. Cancer patients after chemo and radiation therapy d. Deficiency of orotate-phosphoribosyl transferase e. Deficiency of PRPP-amidotransferase

The correct answers are: a. Deficiency of glucose-6-phosphatase, b. Deficiency of hypoxanthine-guanine-phosphoribosyl transferase, c. Cancer patients after chemo and radiation therapy

Which of the following compounds are substrates of ribonucleotide-reductase? Select one or more: a. ADP b. TMP c. AMP d. GMP e. CDP

The correct answers are: a. ADP, e. CDP

Which of the following compounds provide atoms directly to form the pyrimidine ring? Select one or more: a. Carbamoyl phosphate b. Aspartate c. Glutamine d. CO2/ HCO3- e. Oxalacetate

The correct answers are: a. Carbamoyl phosphate, b. Aspartate, c. Glutamine, d. CO2/ HCO3-

Which of the following enzymes catalyse salvage reactions in nucleotide metabolism? Select one or more: a. Uridine kinase b. Cytidine kinase c. Aspartate carbamoyltransferase d. Hypoxanthine-guanine-phosphoribosyl transferase e. PRPP-amidotransferase

The correct answers are: a. Uridine kinase, b. Cytidine kinase, d. Hypoxanthine-guanine-phosphoribosyl transferase

Which of the following enzymes participate in the synthesis of pyrimidine nucleotides? Select one or more: a. PRPP synthetase b. Carbamoyl phosphate synthetase c. Aspartate carbamoyltransferase d. Adenylosuccinate transferase e. Orotate-phosphoribosyltransferase

The correct answers are: a. PRPP synthetase, b. Carbamoyl phosphate synthetase, c. Aspartate carbamoyltransferase, e. Orotate-phosphoribosyltransferase

Which of the following intermediates are derived from degradation of purine nucleotides? Select one or more: a. Hypoxanthine b. Orotate c. N-carbamoyl--aminoisobutyrate d. Xanthine e. Ribose-1-phosphate

The correct answers are: a. Hypoxanthine, d. Xanthine, e. Ribose-1-phosphate

Which of the following intermediates provide N atom directly to form nucleotide bases? Select one or more: a. Amido group of Gln b. Amino group of Glu c. Asp d. Gly e. NH3

The correct answers are: a. Amido group of Gln, c. Asp, d. Gly

Which of the following intermediates provide C atom directly to form nucleotide bases? Select one or more: a. One carbon atom units attached to tertrahydrofolate b. CO2 c. Asp d. Gly e. Methyl-cobalamin

The correct answers are: a. One carbon atom units attached to tertrahydrofolate, b. CO2, c. Asp, d. Gly

Which of the following factors are involved in the overall regulation of de novo purine nucleotide synthesis? Select one or more: a. PRPP inhibits phosphoribosylamine synthesis b. ADP and GDP are inhibitors of PRPP synthetase c. AMP, IMP and GMP inhibit PRPP-amidotransferase d. GMP inhibits adenylosuccinate synthetase e. ATP is a substrate of GMP-synthetase

The correct answers are: b. ADP and GDP are inhibitors of PRPP synthetase, c. AMP, IMP and GMP inhibit PRPP-amidotransferase, e. ATP is a substrate of GMP-synthetase

Select the enzymes of ``de novo'' pyrimidine biosynthesis! Select one or more: a. Pyrimidine phosphoryl transferase b. aspartate carbamoyl transferase c. ornitine carbamoyl transferase d. CTP synthetase

The correct answers are: b. aspartate carbamoyl transferase, d. CTP synthetase

Which of the compound(s) below is/are allosteric inhibitor(s) of PRPP amidotransferase? Select one: a. ATP b. IMP c. PRPP d. NADH

The correct answer is: b. IMP

Which of the following chemotherapeutic agents is an inhibitor of dihydrofolate reductase? Select one: a. 3-azido-3-deoxythymidine (AZT) b. 5-fluorouracil (Fura) c. 6-merkaptopurine (6-MP) d. Cytosine arabinoside (araC) e. methotrexate (MTX)

The correct answer is: e. methotrexate (MTX)

Which pathways require phosphoribosyl pyrophosphate? Select one or more: a. ``de novo'' purine biosynthesis b. ``de novo'' pyrimidine biosynthesis c. Salvage of purine bases d. Salvage of pyrimidine nucleosides

The correct answers are: a. ``de novo'' purine biosynthesis, b. ``de novo'' pyrimidine biosynthesis, c. Salvage of purine bases

Which conditions could result in hyperuricaemia? Select one or more: a. Increased phosphoribosyl pyrophosphate synthesis b. Decreased rate of purine salvage c. Glucose-6-phosphatase deficiency d. Elevated levels of AMP

The correct answers are: a. Increased phosphoribosyl pyrophosphate synthesis, b. Decreased rate of purine salvage, c. Glucose-6-phosphatase deficiency, d. Elevated levels of AMP

Select the false statement related to the metabolism of deoxyribinucleotides Select one: a. Ribonucleotide reductase is regulated by ATP, dATP, dGTP and dTTP. b. dUMP is converted to dTMP by thymidylate synthase, using N5N10-methylene H4folate. c. dTMP can be formed from dCMP by deamination and subsequent methylation. d. Deoxyribose 1-Phosphate is formed during degradation of deoxynucleosides. e. ``de novo'' synthesis uses the deoxy-form of phosphoribosyl pyrophosphate.

The correct answer is: e. ``de novo'' synthesis uses the deoxy-form of phosphoribosyl pyrophosphate.

Glutamine is an N donor in the synthesis of: Select one or more: a. CTP. b. inosinic acid (IMP). c. orotate. d. UMP

The correct answers are: a. CTP b. inosinic acid (IMP). c. orotate. d. UMP

Which of the following statements is not true of the pathway by which purine nucleotides are synthesized? Select one: a. The amino acid glycine is one of the precursors. b. Inosinate is the purine nucleotide that is the precursor of both adenylate and guanylate. c. Deoxyribonucleotides are formed from 5-phosphodeoxyribosyl 1-pyrophosphate. d. CO2 is required for one of the steps in this pathway.

The correct answer is: c. Deoxyribonucleotides are formed from 5-phosphodeoxyribosyl 1-pyrophosphate.

Which of the following statements correctly describes the pathway by which purine nucleotides are synthesized? Select one: a. Purine deoxynucleotides are made by the same path as ribonucleotides, followed by reduction of the ribose moiety. b. The first enzyme in the path is aspartate transcarbamoylase (ATCase). c. The nitrogen in the purine base that is bonded to ribose in the nucleotide is derived originally from glycine. d. The pathway occurs only in plants and bacteria, not in animals. e. The purine rings are first synthesized, then condensed with ribose phosphate.

The correct answer is: a. Purine deoxynucleotides are made by the same path as ribonucleotides, followed by reduction of the ribose moiety.

Orotic aciduria is an inherited metabolic disease in which orotic acid (orotate) accumulates in the tissues, blood, and urine. The metabolic pathway in which the enzyme defect occurs is: Select one: a. epinephrine synthesis. b. purine breakdown. c. purine synthesis. d. pyrimidine breakdown. e. pyrimidine synthesis.

The correct answer is: e. pyrimidine synthesis.

Precursors for the biosynthesis of the pyrimidine ring system include: Select one: a. carbamoyl phosphate and aspartate. b. glutamate, NH3, and CO2. c. glycine and succinyl-CoA. d. glycine, glutamine, CO2, and aspartate.

The correct answer is: a. carbamoyl phosphate and aspartate.

Which two precursors react directly in the synthesis of UMP? Select one: a. aspartate and carbamoyl phosphate. b. glutamate and aspartate. c. glutamate and carbamoyl phosphate. d. glutamine and aspartate. e. glutamine and carbamoyl phosphate.

The correct answer is: a. aspartate and carbamoyl phosphate.

The ribosyl phosphate moiety needed for the synthesis of orotidylate, inosinate, and guanylate is provided most directly by: Select one: a. ribulose 5-phosphate. b. ribose 5-phosphate. c. guanosine 5'-phosphate. d. adenosine 5'-phosphate. e. 5-phosphoribosyl 1-pyrophosphate.

The correct answer is: e. 5-phosphoribosyl 1-pyrophosphate.

Deficiency of folic acid affects the biosynthesis of: Select one: a. UMP b. CMP. c. orotate. d. thymidylate (TMP). e. any pyrimidine nucleotide

The correct answer is: d. thymidylate (TMP)

An intermediate of purine degradation in humans is: Select one: a. glutamate. b. glycine c. succinate. d. urea. e. xanthine

The correct answer is: e. xanthine

Which of the following enzymes is involved into the pyrimidine de novo synthesis? Select one: a. adenine phosphoribosyl transferase b. cytosine phosphoribosyl transferase c. Gln phosphorybosyl-pyrophosphate amidotransferase d. hypoxantin-guanine phosphoribosyl transferase e. orotic acid phosphoribosyl transferase

The correct answer is: e. orotic acid phosphoribosyl transferase

What is the correct name of the enzyme converting inosine to hypoxantine? Select one: a. hypoxantine phosphorybosyl transferase b. inosine kinase c. inosine phosphatase d. purine nucleoside phosphorylase e. xantine oxidase

The correct answer is: d. purine nucleoside phosphorylase

The product of the reaction catalyzed by the thymidylate synthase is ... Select one: a. TDP b. thymidine c. thymine d. TMP e. TTP

The correct answer is: d. TMP

The product of the reaction catalyzed by the adenosine deaminase is ... Select one: a. adenine b. hypoxantine c. IMP d. inosine e. urate

The correct answer is: d. inosine

Which of the following compounds will be reduced by ribonucleotide reductase? Select one: a. UTP b. UMP c. UDP d. TMP e. dUDP

The correct answer is: c. UDP

Which of the following compounds will be deaminated by cytidylate deaminase? Select one: a. dCDP b. cytidine c. CTP d. CMP e. CDP

The correct answer is: d. CMP

Which reaction is catalyzed by 5' nucleotidase? Select one: a. dephosphorylation of nucleoside monophosphates b. dephosphorypation of nucleoside triphosphates c. phosphorybosyl transfer of purines d. phosphorylation of nucleosides monophosphates e. removal of a ribose-5-phosphate from nucleotides

The correct answer is: a. dephosphorylation of nucleoside monophosphates

Identify compound A ## Footnote Select one: a. purine b. guanine c. uracil d. pyrimidine e. adenine

The correct answer is: a. purine

Identify compound A ## Footnote Select one: a. purine b. guanine c. pyrimidine d. adenine e. cytosine

The correct answer is: c. pyrimidine

Identify compound A and compound B ## Footnote Select one: a. compound A is cytosine, compound B is purine b. compound A is purine, compound B is pyrimidine c. compound A is pyrimidine, compound B is purine d. compound A is guanine, compound B is timine.

The correct answer is: b. compound A is purine, compound B is pyrimidine

Examine the figure below. Which statment is TRUE about the biosynthesis of purine and pyrimidine nucleotides? ## Footnote Select one: a. 2′dGTP stimualtes 2′dADP synthesis. b. ATP inhibits 2'CDP synthesis. c. 2′dGTP exerts a positive feedback for its own synthesis. d. 2′dTTP inhibits 2′dGDP synthesis.

The correct answer is: a. 2′dGTP stimualtes 2′dADP synthesis.

Name the source of the carbon atom designated by X. Select one: a. respiratory CO2 b. acetyl-CoA c. another purine base (AMP, GMP) d. IMP e. vitamin B12

The correct answer is: a. respiratory CO2

Name the source of the nitrogen atom designated by X. Select one: a. aspartate b. asparagine c. arginine d. lysine e. N10 -formyltetrahydrofolat

The correct answer is: a. aspartate

Name the source of the atoms highlighted in blue. ## Footnote Select one: a. glycine b. AMP c. arginine d. citrulline e. urea

The correct answer is: a. glycine

Name the source of the nitrogen atom designated by X. Select one: a. glutamine b. creatinine c. carbamide d. carbamyl phoshpate e. NO

The correct answer is: a. glutamine

Name the source of the carbon atom designated by X. ## Footnote Select one: a. "1C"-tetrahydrofolate b. acetyl-CoA c. SAM d. Glutamine e. Arginine

The correct answer is: a. "1C"-tetrahydrofolate

Name the source of the carbon atom designated by X. ## Footnote Select one: a. N5,N10-methenyltetrahydrofolate b. mycophenolic acid c. methylhydrofolate d. azaserine e. glutamate

The correct answer is: a. N5,N10-methenyltetrahydrofolate

Each source of the de novo synthesized purine are marked with letters A-F below. Which atoms require folic acid for their presence in the molecule? Find the correct pair. ## Footnote Select one: a. E-C b. A-C c. F-D d. B-D e. A-E

The correct answer is: a. E-C (E=N10- Formyltetrahydrofolate, C= N5,N10- Methenyltetrahydrofolate)

Each source of the de novo synthesized purine are marked with letters A-F below. Which atoms require folic amino acid for their presence in the molecule? Find the correct option. ## Footnote Select one: a. E-C b. A-F-C c. D-B d. C-A e. B-F-C

The correct answer is: a. E-C (E=N10- Formyltetrahydrofolate, C= N5,N10- Methenyltetrahydrofolate)

Select the compound that is NOT necessary for de novo synthesizing the compound below: ## Footnote Select one: a. arginine b. glycine c. respiratory CO2 d. N10-formyltetrahydrofolate e. aspartate

The correct answer is: a. arginine

Select the compound that is NOT a carbon source when de novo synthesizing the following compound: ## Footnote Select one: a. acyl-CoA b. glycine c. respiratory CO2 d. N10-formyltetrahydrofolate e. N5,N10-methenyltetrahydrofolate

The correct answer is: a. acyl-CoA

Identify Enzyme X ## Footnote Select one: a. IMP dehydrogenase b. IMP oxygenase c. xanthosine oxidoreductase d. xanthosine kinase e. NADH dehydrogenase

The correct answer is: a. IMP dehydrogenase

Identify Enzyme X ## Footnote Select one: a. adenylosuccinate synthase b. IMP succinyltransferase c. adenylosuccinate kinase d. IMP aminotransferase e. adenylosuccinate deaminase

The correct answer is: a. adenylosuccinate synthase

Identify Enzyme X ## Footnote Select one: a. adenylosuccinase b. AMP synthase c. AMP synthetase d. adenylosuccinate dehydrogenase e. AMP kinase

The correct answer is: a. adenylosuccinase

Identify Enzyme X ## Footnote Select one: a. transamidinase b. GMP synthase c. xanthosine aminotransferase d. xanthosine glumamine transferase e. GMP kinase

The correct answer is: a. transamidinase

Identify the missing Compound X Select one: a. guanosine monophosphate b. hypoxanthine c. uric acid d. aminoxanthosine monophosphate e. xanthine

The correct answer is: a. guanosine monophosphate

Identify the missing Compound X Select one: a. xanthosine monophosphate b. hypoxanthine c. deoxy inosine monophosphate d. guanosine monophosphate e. uracil monophosphate

The correct answer is: a. xanthosine monophosphate

Identify the missing Compound X ## Footnote Select one: a. inosine monophosphate b. inositol monophosphate c. indole monophosphate d. 6-oxopurine monophosphate e. 6-oxo-5-aminopurine monophosphate

The correct answer is: a. inosine monophosphate

Identify the missing Compound X ## Footnote Select one: a. adenylosuccinate b. succinyladenine monophosphate c. succinylinosine monophosphate d. 6-oxopurine monophosphate e. 6-oxo-5-aminopurine monophosphate

The correct answer is: a. adenylosuccinate

Identify the missing Compound X ## Footnote Select one: a. adenosine monophosphate b. adenyl monophosphate c. hypoxanthine monophosphate d. xanthine monophosphate e. 6-amino-inosine monophosphate

The correct answer is: a. adenosine monophosphate

Find out which cofactors are 'B' and 'C' Select one: a. B is NAD+, C is NADH + H+ b. B is NADH + H+, C is NAD+ c. B is NAD+, C is FADH2 d. B is FAD, C is FADH2 e. B is FADH2, C is FAD

The correct answer is: a. B is NAD+, C is NADH + H+

Indentify reactant pair 'X' and 'Y' in the reaction marked with 'A' ## Footnote Select one: a. X is glutamine, Y is glutamate. b. X is asparagine, Y is aspartate. c. X is glutamate, Y is alpha-ketoglutarate d. X is alanine, Y is pyruvate e. X is aspartate, Y is oxaloacetate

The correct answer is: a. X is glutamine, Y is glutamate.

Examine the figure below. Identify 'compound X'. AMPS is adenylosuccinate, XMP is xanthosine monophosphate. Select one: a. Inosine monophosphate b. Purine c. Hypoxanthine monophosphate d. 5-phosphoribosyl 1-pyrophosphate (PRPP) e. Aminoimidazole ribosyl-5-phosphate

The correct answer is: a. Inosine monophosphate

Examine the figure below. Identify 'compound X'. IMP is inosine monophosphate, XMP is xanthosine monophosphate. Select one: a. Adenylosuccinate b. Adenosine c. Adenine d. 5-phosphoribosyl 1-pyrophosphate (PRPP) e. Aminoimidazole carboxylate ribosyl-5-phosphate

The correct answer is: a. Adenylosuccinate

Examine the figure below. Identify 'compound X'. IMP is inosine monophosphate, AMPS is adenlyosuccinate monophosphate. Select one: a. Xanthosine monophosphate b. Guanidine monophosphate c. Guanosine monophosphate d. Hypoxanthine monophosphate e. Uric acid

The correct answer is: a. Xanthosine monophosphate

Select the correct statement below: ## Footnote Select one: a. AMP inhibits adenylosuccinate synthase b. GMP stimulates IMP dehydrogenase c. GTP inhibits adenylosuccinate synthase d. ATP inhibits adenylosuccinate synthase e. GTP promotes IMP dehydrogenase

The correct answer is: a. AMP inhibits adenylosuccinate synthase

Select the false statement below: ## Footnote Select one: a. ATP promotes IMP dehydrogenase b. ATP promotes transamidinase c. AMP inhibits adenylosuccinate synthase d. GMP inhibits IMP dehydrogenase e. GTP promotes adenylosuccinate synthetase

The correct answer is: a. ATP promotes IMP dehydrogenase

Select the false statement below: ## Footnote Select one: a. GMP stimulates IMP dehydrogenase b. If ATP synthesis is deficient, GTP synthesis is decreased. c. AMP inhibits adenylosuccinate synthase d. If GTP synthesis is deficient, ATP synthesis is decreased. e. GTP stimulates adenylosuccinate synthase

The correct answer is: a. GMP stimulates IMP dehydrogenase

Select the correct statement below: ## Footnote Select one: a. GMP inhibits IMP dehydrogenase b. If ATP synthesis is deficient, GTP synthesis is increased compensatory. c. GTP stimulates adenylosuccinate lyase d. If GTP synthesis is deficient, ATP synthesis is increased compensatory. e. ATP inhibits adenylate kinase

The correct answer is: a. GMP inhibits IMP dehydrogenase

Indentify 'compound X' ## Footnote Select one: a. AMP b. CMP c. TMP d. UMP e. CDP

The correct answer is: a. AMP

Indentify 'compound X' Select one: a. GMP b. CMP c. Hypoxanthine d. Guanine monophosphate e. Cytidine monophosphate

The correct answer is: a. GMP

Identify 'enzyme X'. ## Footnote Select one: a. Thioredoxin reductase b. Thioredoxin oxidase c. Thioredoxin convertase d. Thioredoxin oxidoreductase e. Thioredoxin dehydrogenase

The correct answer is: a. Thioredoxin reductase

Identify 'endproduct X'. ## Footnote Select one: a. 2′-Deoxyribonucleoside diphosphate b. 1′-Deoxyribonucleoside diphosphate c. 3′-Deoxyribonucleoside diphosphate d. 4′-Deoxyribonucleoside diphosphate e. 5′-Deoxyribonucleoside diphosphate

The correct answer is: a. 2′-Deoxyribonucleoside diphosphate

Indentify 'Cofactor X' that is needed for the reaction below: ## Footnote Select one: a. NADPH + H+ b. NAD+ c. NADH + H+ d. FADH2 e. FMN

The correct answer is: a. NADPH + H+

What is the role of the following reaction? ## Footnote Select one: a. Provides deoxyribonucleoside diphosphates for DNA synthesis and repair. b. Provides deoxyribonucleoside diphosphates for DNA repair. c. Provides deoxyribonucleoside diphosphates for DNA synthesis. d. Provides deoxyribonucleoside diphosphates for DNA and RNA synthesis. e. Provides deoxyribonucleoside diphosphates for DNA and RNA repair.

The correct answer is: a. Provides deoxyribonucleoside diphosphates for DNA synthesis and repair.

Indentify 'cofactor X' that is oxidized and then reduced by the enzyme highlighted with red in the following reaction: ## Footnote Select one: a. Thioredoxin b. Thiamine pyrophosphate c. NAD+ d. Biotin e. Pyridoxal phosphate

The correct answer is: a. Thioredoxin

Examine the figure below. Identify the missing enzyme 'Enzyme X'. Select one: a. Dihydroorotase b. DHOA synthase c. DHOA synthetase d. Carbamoyl dehydratase e. CAA dehydrogenase

The correct answer is: a. Dihydroorotase

Examine the figure below. Identify the missing enzyme 'Enzyme X'. Select one: a. Orotidylic acid decarboxylase b. Orotate dehydrogenase c. Orotic acid decarboxylase d. Uridine monophosphate synthase e. Uridine monophosphate synthetase

The correct answer is: a. Orotidylic acid decarboxylase

Examine the figure below. Identify the missing enzyme 'Enzyme X'. ## Footnote Select one: a. CTP synthase b. UTP transaminase c. UTP-glutamine transferase d. Pyrimidine nucleotide convertase e. Uridine triphosphate synthase

The correct answer is: a. CTP synthase

Examine the figure below. Identify the missing enzyme 'Enzyme X'. ## Footnote Select one: a. Thymidylate synthase b. dUMP dehydrogenase c. dUMP-N-methyltransferase d. dUMP-N-methenyltransferase e. Folic acid dehydrogenase Clear my choice

The correct answer is: a. Thymidylate synthase

Examine the figure below. Identify the missing enzyme 'Enzyme X'. ## Footnote Select one: a. Ribonucleotide reductase b. UDP dehydrogenase c. UDP reductase d. dUDP synthase

The correct answer is: a. Ribonucleotide reductase

Carbamoyl phosphate synthase II (figure below) is located in the ## Footnote Select one: a. cytosol b. mitochondria c. endoplasmic reticula d. peroxisome e. nucleus

The correct answer is: a. cytosol

Which compound is a pyrimidine analog that is an alternative substrate of Orotate phosphoribosyltransferase enzyme? ## Footnote Select one: a. 5-fluorouracil b. 8-Azaguanine c. 6-Thioguanine d. mycophenolic acid Clear my choice

The correct answer is: a. 5-fluorouracil

Select the FALSE statement about the following pathway ## Footnote Select one: a. The pathway is located in the mitochondrial matrix b. The pathway is energetically costly. c. Several steps of the pathway are catalyzed by multifunctional proteins. d. The carbamoyl phosphate pool for urea and nucleotide synthesis is separated. e. Channeling of the intermediates of pyrimidine biosynthesis serves as a facilitator factor.

The correct answer is: a. The pathway is located in the mitochondrial matrix

Examine the figure below. Identify the missing compund 'Compound X'. Select one: a. Carbamoyl phosphate b. Carbamoyl diphosphate c. Carbamoyl triphosphate d. Methylcarbamoyl phosphate e. Carbamoyl pyrophosphate Clear my choice

The correct answer is: a. Carbamoyl phosphate

Examine the figure below. Identify the missing compund 'Compound X'. ## Footnote Select one: a. Orotic acid b. Orotate phosphate c. Xanthine d. Hypoxanthine e. Orotate phosphoribose

The correct answer is: a. Orotic acid

Select the FALSE statement about the following regulation system: ## Footnote Select one: a. TDP promotes phosphoribosyl pyrophosphate synthesis b. CTP inhibits carbamoyl aspartic acid synthesis c. UTP inhibits carbamoyl phosphate synthesis d. Phosphoribosyl pyrophosphate promotes carbamoyl phosphate synthesis

The correct answer is: a. TDP promotes phosphoribosyl pyrophosphate synthesis

Examine the figure below. Which is the factor that directly regulates 'Reaction A'? CAP is carbamoyl phosphate. Select one: a. The level of purine nucleotides. b. The level of DHOA c. The level of ATP d. The level of CTP. e. The level of TMP.

The correct answer is: a. The level of purine nucleotides.

Examine the figure below. Identify the missing 'Compound X'. ## Footnote Select one: a. Adenosine b. Adenine c. Adenosine monophosphate d. Adenosine diphosphate e. Adenosine triphosphate

The correct answer is: a. Adenosine

Examine the figure below. Identify the missing 'Compound X'. ## Footnote Select one: a. Inosine b. 2'-deoxyadenosine c. Orotic acid d. Guanosine e. Phosphoribosyl pyrophosphate

The correct answer is: a. Inosine

Examine the figure below. Identify the missing 'Compound X'. Select one: a. Guanosine b. 2'-deoxyguanosine c. Guanidine d. Guanosine monophosphate e. Phosphoribosyl pyrophosphate Clear my choice

The correct answer is: a. Guanosine

Examine the figure below. Identify the missing 'Compound X'. ## Footnote Select one: a. Hypoxanthine b. Purine c. Pyrimidine d. Allopurinol e. Xanthosine

The correct answer is: a. Hypoxanthine

Examine the figure below. Identify the missing 'Compound X'. ## Footnote Select one: a. Guanine b. Purine c. Xanthosine d. Guanidine e. Inositol monophosphate

The correct answer is: a. Guanine

Examine the figure below. Identify the missing 'Compound X'. ## Footnote Select one: a. Xanthine b. Xanthosine c. Urea d. Orotic acid e. xylometazoline

The correct answer is: a. Xanthine

Examine the figure below. Identify the missing 'Compound X'. ## Footnote Select one: a. Uric acid b. Urea c. Uracil d. Uridine e. carbamide

The correct answer is: a. Uric acid

Examine the figure below. Identify the missing 'Enzyme X'. ## Footnote Select one: a. Adenosine deaminase b. Adenosine dehydrogenase c. Adenosine phosphatase d. Adenosine kinase e. Purine nucleotide deaminase

The correct answer is: a. Adenosine deaminase

Examine the figure below. Identify the missing 'Enzyme X'. ## Footnote Select one: a. Xanthine oxidase b. Urate synthase c. Purine nucleoside dehydrogenase d. Purine nucleoside oxidase e. Xanthine deaminase

The correct answer is: a. Xanthine oxidase

Examine the figure below. Identify the missing 'Enzyme X'. ## Footnote Select one: a. Purine nucleoside phosphorylase b. Purine nucleotide phosphatase c. Inosine dephosphorylase d. Guanosine phosphorylase e. Purine nucleoside deaminase

The correct answer is: a. Purine nucleoside phosphorylase

Examine the figure below. Which statment is TRUE about the biosynthesis of purine and pyrimidine nucleotides? ## Footnote Select one: a. ATP stimulates 2′dCDP synthesis. b. ATP inhibits 2'UDP synthesis. c. 2′dTTP exerts a positive feedback for its own synthesis. d. 2′dGTP inhibits the synthesis of 2′dADP.

The correct answer is: a. ATP stimulates 2′dCDP synthesis.

The atelectasis in neonatal respiratory distress syndrome is caused by: Select one or more: a. Lack of dipalmitoyl-phosphatidylcholine in the surfactant of the lungs b. Deficient spreading of the phospholipid bilayer on the water-air interface in the alveoli c. Inability of the immature neonatal lung to form lamellar bodies d. High content of saturated fatty acids in the phosphatidylcholine component of the surfactant e. Increased surface tension of the fluid layer of the lungs

The correct answers are: a. Lack of dipalmitoyl-phosphatidylcholine in the surfactant of the lungs, b. Deficient spreading of the phospholipid bilayer on the water-air interface in the alveoli, e. Increased surface tension of the fluid layer of the lungs

Which lipids are essential for the normal function of the alveolar surfactant? Select one or more: a. Dipalmitoyl-phosphatidylcholine b. Oleyl-palmitoyl-phosphatidylcholine c. Cholesteryl-esters d. Phosphatidylethanolamine e. Sphingomyelin

The correct answers are: a. Dipalmitoyl-phosphatidylcholine, d. Phosphatidylethanolamine

The triacylglycerols (TAG) form spontaneously a stable separate phase in water environment, because: Select one: a. Droplets of TAG cause an increase in the entropy of the water phase, which overcomes the positive change of enthalpy for the disruption of intermolecular interactions between the water molecules b. Droplets of TAG cause a decrease in the entropy of the water phase, which overcomes the positive change of enthalpy for the disruption of intermolecular interactions between the water molecules c. The polar phosphodiester bonds of TAGs are hidden in the core of the molecule and thus these are not accessible for the water molecules to form homogeneous solution d. The TAG molecules bind to each other with significantly stronger forces than the water molecules e. The TAGs are emulsifiers

The correct answer is: a. Droplets of TAG cause an increase in the entropy of the water phase, which overcomes the positive change of enthalpy for the disruption of intermolecular interactions between the water molecules

Select the statements valid for the reversed hexagonal structures (HII) of phospholipids Select one or more: a. HII is essential for the normal barrier function of the cellular membranes b. HII is formed mainly by phosphatidylcholine, phosphatidylserine and phosphatidylinositol c. HII is essential for the fusion and rearrangements of membranes d. HII is permanently exposed to the outer surface of the plasma membrane e. HII is formed mainly by phosphatidylethanolamine and diacylglycerol

The correct answers are: c. HII is essential for the fusion and rearrangements of membranes, e. HII is formed mainly by phosphatidylethanolamine and diacylglycerol

Which statements are valid for both phosphatidylserine and phosphatidylinositol-4,5,-bisphosphate? Select one or more: a. Present predominantly in the outer layer of the plasma membrane b. Present predominantly in the inner layer of the plasma membrane c. Anionic phospholipids d. The biosynthesis in mammalian tissues proceeds through diacylglycerol activated with CDP e. The biosynthesis in mammalian tissues proceeds through head group activated with CDP

The correct answers are: b. Present predominantly in the inner layer of the plasma membrane, c. Anionic phospholipids

Select the substrates of the mammalian phosphatidylserine synthase I Select one or more: a. Phosphatidylcholine b. Phosphatidylethanolamine c. CTP d. Serine e. ATP f. diacylglycerol g. CDP-diacylglycerol

The correct answers are: a. Phosphatidylcholine, d. Serine

Select the statement, which is most relevant to the maintenance of appropriate ratio of cationic and anionic phospholipids in the membranes Select one: a. The CTP-phosphocholine cytidylyltransferase binds with high affinity to reversed hexagonal phase membranes and with low affinity to ordered gel phase membranes b. The CTP-phosphocholine cytidylyltransferase is inhibited by cationic phospholipids and activated by anionic phospholipids c. The CTP-phosphocholine cytidylyltransferase is active in dephosphorylated state d. Due to its higher negative charge the phosphorylated CTP-phosphocholine cytidylyltransferase binds to membranes with high content of cationic phospholipids e. Anionic phospholipids donate negatively charged phosphate groups to CTP-phosphocholine cytidylyltransferase, which is inhibited in this way

The correct answer is: a. The CTP-phosphocholine cytidylyltransferase binds with high affinity to reversed hexagonal phase membranes and with low affinity to ordered gel phase membranes

Select the enzymes involved in the control of the phosphatidylcholine biosynthesis: Select one or more: a. glycerol-3-phosphate acyltransferase b. monoacylglycerol-3-phosphate acyltransferase c. phosphatidate phosphohydrolase d. CTP-phosphocholine cytidylyltransferase e. diacylglycerol-acyltransferase f. choline kinase g. CDP-diacylglycerol phosphocholine transferase

The correct answers are: a. glycerol-3-phosphate acyltransferase, c. phosphatidate phosphohydrolase, d. CTP-phosphocholine cytidylyltransferase, choline kinase

The synthesis of both glycerophospholipids and triacylglycerols involves: Select one: a. CDP-choline. b. CDP-diacylglycerol. c. phosphatidate phosphatase. d. phosphatidic acid. e. phosphoethanolamine.

The correct answer is: d. phosphatidic acid.

A strategy that is not employed in the synthesis of phospholipids is: Select one: a. condensation of CDP-alcohol with diacylglycerol. b. condensation of CDP-diacylglycerol with alcohol. c. condensation of CDP-diacylglycerol with CDP-alcohol. d. exchange of free alcohol with head group alcohol of phospholipid

The correct answer is: c. condensation of CDP-diacylglycerol with CDP-alcohol.

In the synthesis of phosphatidylcholine from phosphatidylethanolamine, the methyl group donor is: Select one: a. a tetrahydrofolate derivative. b. choline. c. methanol. d. S-adenosylmethionine (adoMet). e. serine.

The correct answer is: d. S-adenosylmethionine (adoMet).

All glycerol-containing phospholipids are synthesized from: Select one: a. phosphatidic acid. b. mevalonate. c. gangliosides. d. ceramide.

The correct answer is: a. phosphatidic acid.

Palmitoyl-CoA, without intervening catabolic steps, is most directly a precursor of: Select one: a. cholesterol. b. malonyl-CoA. c. sphingosine. d. squalene.

The correct answer is: c. sphingosine.

CDP-diglyceride is not involved in the biosynthesis of: Select one: a. phosphatidylcholine. b. phosphatidylglycerol. c. phosphatidylserine. d. sphingomyelin.

The correct answer is: d. sphingomyelin.

Which of the following is true of sphingolipid synthesis? Select one: a. All of the carbon atoms of palmitate and serine are incorporated into sphingosine. b. CDP-sphingosine is the activated intermediate. c. CO2 is produced during the synthesis of ceramide from palmitate and serine. d. Glucose 6-phosphate is the direct precursor of the glucose in cerebrosides. e. Phosphatidic acid is a key intermediate in the pathway.

The correct answer is: c. CO2 is produced during the synthesis of ceramide from palmitate and serine.

Which enzyme is not involved into the heme biosynthesis? Select one: a. delta-aminolevulinic acid dehydratase b. delta-aminolevulinic acid synthase c. Heme oxygenase d. urophorphyrinogen III cosynthase e. urophorphyrinogen III synthase

The correct answer is: c. Heme oxygenase

Which statements are true? Select one or more: a. delta-aminolevulinic acid synthase is localized in the mitochondrion. b. the coenzyme of delta-aminolevulinic acid synthase is NADH c. delta-aminolevulinic acid dehydratase is sensitive to lead poisoning. d. formation of uroporphirinogen III is an enzyme-independent step.

The correct answers are: a. delta-aminolevulinic acid synthase is localized in the mitochondrion. c. delta-aminolevulinic acid dehydratase is sensitive to lead poisoning.

Which statements are true? Select one or more: a. Glucuronidation of bilirubin takes place in the liver. b. Bilirubin is poorly soluble in water. c. In the clinical setting, conjugated bilirubin is measured as indirect bilirubin. d. Biliary tract obstruction results in elevation of conjugated bilirubin level in the plasma.

The correct answers are: a. Glucuronidation of bilirubin takes place in the liver. b. Bilirubin is poorly soluble in water. d. Biliary tract obstruction results in elevation of conjugated bilirubin level in the plasma.

What is the nitrogen donor in heme biosynthesis? Select one: a. Asparagine b. Aspartate c. Glutamate d. Glutamine e. Glycine

The correct answer is: e. Glycine

Which statement is true? Select one: a. Conjugated bilirubin is less soluble in water than the unconjugated form. b. Liver diseases reduce conjugated bilirubin in the serum. c. Serum conjugated bilirubin is low in biliary tract obstruction. d. The serum level of conjugated bilirubin is high in UDP glucuronidase deficiency. e. The substance deposited in skin and sclera in jaundice is biliverdin.

The correct answer is: b. Liver diseases reduce conjugated bilirubin in the serum.

Bile pigments are: Select one: a. formed by oxidation of sterols. b. formed in the degradation of heme. c. responsible for light reception in the vertebrate eye. d. the products of purine degradation.

The correct answer is: b. formed in the degradation of heme.

Neonatal jundice can be caused by ... Select one or more: a. low activity of UDP-glucuronyl transferase b. low rate of UDP-glucuronic acid production c. accelerated hemolysis

The correct answers are: a. low activity of UDP-glucuronyl transferase, b. low rate of UDP-glucuronic acid production, c. accelerated hemolysis

The substrates of the ALA synthase are .... Select one: a. alanine and acetylCoA b. alanine and succinylCoA c. phosphorybosyl pyrophosphate and glutamine d. pyruvate and NADH e. SuccinylCoA and glycine

The correct answer is: e. SuccinylCoA and glycine

The porphobilinogen is formed by ... Select one: a. ALA synthase b. ALA reductase c. ALA oxidase d. ALA dehydratase e. ALA decarboxylase

The correct answer is: d. ALA dehydratase

The correct answer is: b. mitochondria

What is the weakly androgenic steroid that is synthesized in the adrenal gland? Select one: a. testosterone b. progesterone c. pregnenolone d. dehydroepiandrosterone e. corticosterone

The correct answer is: d. dehydroepiandrosterone

Which steroid hormone needs P450aro (aromatase) enzyme for its biosynthesis? Select one: a. aldosterone b. cortisol c. estradiol d. progesterone e. testosterone

The correct answer is: c. estradiol

What is the primary role of the steroidogenic acute regulatory protein (StAR) in the biosynthesis of steroid hormones ? Select one: a. By acting on the endoplasmic reticular membrane it promotes the activity of P-450 reductase b. By acting on the endoplasmic reticular membrane it promotes the interaction between P-450 reductase and P-450c21 (steroid 21 hydroxylase) c. By acting on the outer mitochondrial membrane it promotes cholesterol delivery to cytochrome P-450scc (cholesterol side chain cleavage enzyme) d. By acting on the outer mitochondrial membrane it promotes the activity of adrenodoxin reductase e. By acting on the outer mitochondrial membrane it promotes the interaction between P-450scc and adrenodoxin

The correct answer is: c. By acting on the outer mitochondrial membrane it promotes cholesterol delivery to cytochrome P-450scc (cholesterol side chain cleavage enzyme)

Which of the following steroidogenic enzymes catalyzes the formation of the aldehyde group during aldosterone biosynthesis? Select one: a. P-450c11 (11-hydroxylase) b. P-450aldo (11-hydroxylase) c. P-450c17 (17-hydroxylase) d. P-450c21 (21-hydroxylase) e. 17 hydroxysteroid dehydrogenase

The correct answer is: b. P-450aldo (11-hydroxylase)

What is the sequence of hydroxylation steps of progesterone when cortisol is biosynthesized from cholesterol? (the numbers designate the carbon atoms present in progesterone) Select one: a. 17,21,11 b. 17,11,21 c. 11,21,17 d. 21,11,17 e. 11,17,21

The correct answer is: a. 17,21,11

Which steroidogenic pathway does not involve 21-hydroxylation? Select one or more: a. Aldosterone b. Cortisol c. Testosterone d. Progesterone

The correct answers are: c. Testosterone, d. Progesterone

Which cytochrome does not participate in the biosynthesis of aldosterone from cholesterol? Select one or more: a. P-450scc (cholesterol side chain cleavage enzyme) b. P-450c17 (17- hydroxylase) c. P-450c21 (21-hydroxylase) d. P-450aro (aromatase)

The correct answers are: b. P-450c17 (17- hydroxylase), d. P-450aro (aromatase)

Which cytochrome participates in the biosynthesis of aldosterone from cholesterol? Select one or more: a. P-450scc (cholesterol side chain cleavage enzyme) b. P-450c17 (17- hydroxylase) c. P-450c21 (21-hydroxylase) d. P-450aro (aromatase)

The correct answers are: a. P-450scc (cholesterol side chain cleavage enzyme), c. P-450c21 (21-hydroxylase)

Which cytochrome does not participate in the biosynthesis of cortisol from cholesterol? Select one: a. P-450scc (cholesterol side chain cleavage enzyme) b. P-450c17 (17- hydroxylase) c. P-450aldo (aldehyde synthase) d. P-450c21 (21-hydroxylase)

The correct answer is: c. P-450aldo (aldehyde synthase)

Which cytochrome participates in the biosynthesis of cortisol from cholesterol? Select one or more: a. P-450scc (cholesterol side chain cleavage enzyme) b. P-450c17 (17- hydroxylase) c. P-450aldo (aldosterone synthase) d. P-450c21 (21-hydroxylase)

The correct answers are: a. P-450scc (cholesterol side chain cleavage enzyme), b. P-450c17 (17- hydroxylase), d. P-450c21 (21-hydroxylase)

Which reaction(s) is catalyzed by the C-450aldo (aldehyde synthase) enzyme of the glomerular zone in the adrenal gland? Select one: a. 11--hydroxylation b. 11--hydroxylation and 18-hydroxylation c. 11--hydroxylation, 18-hydroxylation and 18-hydroxymethyl oxidation d. 18-hydroxylation e. 18-hydroxylation and 18-hydroxymethyl oxidation

The correct answer is: c. 11--hydroxylation, 18-hydroxylation and 18-hydroxymethyl oxidation

Zona glomerulosa of the adrenal cortex is the major site of synthesis of the following substances: Select one or more: a. estradiol b. litocholate c. progesterone d. cortisol e. aldosterone

The correct answer is: e. aldosterone

The following substances are synthesized in the zona fasciculata of the adrenal cortex Select one or more: a. angiotensin II b. corticosterone c. cortisol d. angiotensinogen e. testosterone

The correct answers are: b. corticosterone, c. cortisol

Which hormones can be synthesized from pregnenolone? Select one or more: a. Angiotensin I b. Progesterone c. Dopamine d. Testosterone e. Corticosterone

The correct answers are: b. Progesterone, d. Testosterone, e. Corticosterone

Which mechanisms regulate the synthesis of testosterone? Select one or more: a. Luteinizing hormone (LH) activates the adenylate cyclase in Leydig cells b. Elevated cAMP level promotes the cleavage of the cholesterol side chain c. Cholesterol side chain cleavage is inhibited by cAMP d. Testosterone induces the release of gonadotropin-releasing hormone (GnRH) from the hypothalamus

The correct answers are: a. Luteinizing hormone (LH) activates the adenylate cyclase in Leydig cells, b. Elevated cAMP level promotes the cleavage of the cholesterol side chain

Which compound is not synthesized from cholesterol? Select one: a. Dehydroepiandrosterone b. Litocholate c. Progesterone d. ACTH e. Vitamin D

The correct answer is: d. ACTH

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