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Flashcards in Biochem Deck (226):
1

Which of the following is NOT required for protein synthesis
A. mRNA
B. large ribosomal unit
C. Pyridoxine
D. Methionine
E. NOTA

E. NOTA

mRNA, large ribosomal unit, pyridoxine (vit B6),
and methionine are all required for protein synthesis

2

What do you call vectors which are extrachromosomal circular pieces of DNA that are
found in bacteria?
A. Bacteriophages
B. Hybrids
C. Plasmids
D. Palindromes

C. Plasmids

Plasmid vectors or plasmids are extrachromosomal circular pieces of DNA that are found in bacteria. Bacteriophages are viruses that infect and replicate within bacteria.

3

What term is used to describe the resistance of pH to change in addition of H+ or OH?
A. Bond strength
B. Dissociation strength
C. Titration
D. Buffering

D. Buffering

Buffers consist of solutions of acid-base conjugate pairs (eg: acetic acid and
acetate)

4

Homeostasis includes which of the following:
A. Maintenance of electrolyte concentration
B. Maintenance of appropriate pH
C. Consideration of water distribution in the body
D. AOTA

D. AOTA

5

What is the normal range of blood pH?
A. 7.25 - 7.65
B. 7.35 - 7.45
C. 6.8 - 7.35
D. 6.45 - 7.45

B. 7.35 - 7.45

6

What is the concentration (in moles/liter) of the hydrogen ion if pH of a solution is 7?
A. 7
B. 7x10-7
C. 1x10-7
D. 5x10-7

C. 1x10-7

pH = - log [H+],so, [H+] = inverse log [-pH] = 1x10-7

7

Pathways involved in the breakdown of larger molecules, commonly involving oxidative
reactions:

A. Anabolic pathways
B. Catabolic pathways
C. Amphibolic pathways
D. Oxidative pathways

B. Catabolic pathways

Catabolic pathways break down molecules and produce energy. Anabolic
pathways synthesize molecules and require energy. Amphibolic pathways involves both: break
down of a large molecule to produce energy that will then be utilized to synthesize more complex molecules (classic example: Kreb’s cycle).

8

The urea cycle takes place:

A. In the cytosol and mitochondria of all body tissues that have a nucleus
B. In the kidney where urea is excreted in the urine
C. In the liver’s cytosol and mitochondria
D. In the mitochondria, golgi complex, and endoplasmic reticulum of hepatic sinusoids

C. In the liver’s cytosol and mitochondria

9

A negative nitrogen balance is present in all of the following conditions, except:

A. Pregnancy
B. Advanced ulcer
C. Trauma or tissue injury
D. Fasting states

A. Pregnancy

Negative nitrogen balance means that the amount of nitrogen excreted is greater
than the amount of nitrogen ingested. It is associated with burns, hyPERthyroidism, fever, serious tissue injury, and during periods of fasting.

10

Which subclass of oxidoreductases oxidizes a substrate by a reduction reaction that transfers hydrides to an electron acceptor?

A. Dehydrogenases
B. Oxidases
C. Oxygenases
D. Peroxidases
E. Hydroxylases
F. Reductases

A. Dehydrogenases

Oxidoreductases has 6 categories:

1) Dehydrogenases - oxidize a substrate by reducing an electron acceptor via transfer of hydride (H-)

2) Oxidases - involve donation of H to O2 to form H20 or H2O2

3) Oxygenases - oxidize a substrate by transferring the oxygen from molecular oxygen (02)
to it

4) Peroxidases - use hydrogen peroxide (H2O2) as optimal substrate

5) Hydroxylases - transfer hydroxyl group (-OH) to organic compounds

6) Reductases - catalyze reduction reactions

11

Which subclass of oxidoreductases oxidizes a substrate by donating a H to O2 to form H20 or H2O2?

A. Dehydrogenases
B. Oxidases
C. Oxygenases
D. Peroxidases
E. Hydroxylases
F. Reductases

B. Oxidases

Oxidoreductases has 6 categories:

1) Dehydrogenases - oxidize a substrate by reducing an electron acceptor via transfer of hydride (H-)

2) Oxidases - involve donation of H to O2 to form H20 or H2O2

3) Oxygenases - oxidize a substrate by transferring the oxygen from molecular oxygen (02)
to it

4) Peroxidases - use hydrogen peroxide (H2O2) as optimal substrate

5) Hydroxylases - transfer hydroxyl group (-OH) to organic compounds

6) Reductases - catalyze reduction reactions

12

Which subclass of oxidoreductases oxidizes a substrate by transferring the oxygen from molecular oxygen (02) to it?

A. Dehydrogenases
B. Oxidases
C. Oxygenases
D. Peroxidases
E. Hydroxylases
F. Reductases

C. Oxygenases

Oxidoreductases has 6 categories:

1) Dehydrogenases - oxidize a substrate by reducing an electron acceptor via transfer of hydride (H-)

2) Oxidases - involve donation of H to O2 to form H20 or H2O2

3) Oxygenases - oxidize a substrate by transferring the oxygen from molecular oxygen (02) to it

4) Peroxidases - use hydrogen peroxide (H2O2) as optimal substrate

5) Hydroxylases - transfer hydroxyl group (-OH) to organic compounds

6) Reductases - catalyze reduction reactions

13

Which subclass of oxidoreductases oxidizes a substrate by using hydrogen peroxide (H2O2) as optimal substrate?

A. Dehydrogenases
B. Oxidases
C. Oxygenases
D. Peroxidases
E. Hydroxylases
F. Reductases

D. Peroxidases

Oxidoreductases has 6 categories:

1) Dehydrogenases - oxidize a substrate by reducing an electron acceptor via transfer of hydride (H-)

2) Oxidases - involve donation of H to O2 to form H20 or H2O2

3) Oxygenases - oxidize a substrate by transferring the oxygen from molecular oxygen (02)
to it

4) Peroxidases - use hydrogen peroxide (H2O2) as optimal substrate

5) Hydroxylases - transfer hydroxyl group (-OH) to organic compounds

6) Reductases - catalyze reduction reactions

14

Which subclass of oxidoreductases oxidizes a substrate by transfering hydroxyl group (-OH) to organic compounds?

A. Dehydrogenases
B. Oxidases
C. Oxygenases
D. Peroxidases
E. Hydroxylases
F. Reductases

E. Hydroxylases

Oxidoreductases has 6 categories:

1) Dehydrogenases - oxidize a substrate by reducing an electron acceptor via transfer of hydride (H-)

2) Oxidases - involve donation of H to O2 to form H20 or H2O2

3) Oxygenases - oxidize a substrate by transferring the oxygen from molecular oxygen (02)
to it

4) Peroxidases - use hydrogen peroxide (H2O2) as optimal substrate

5) Hydroxylases - transfer hydroxyl group (-OH) to organic compounds

6) Reductases - catalyze reduction reactions

15

Which subclass of oxidoreductases oxidizes a substrate by catalyzing reduction reactions?

A. Dehydrogenases
B. Oxidases
C. Oxygenases
D. Peroxidases
E. Hydroxylases
F. Reductases

F. Reductases

Oxidoreductases has 6 categories:

1) Dehydrogenases - oxidize a substrate by reducing an electron acceptor via transfer of hydride (H-)

2) Oxidases - involve donation of H to O2 to form H20 or H2O2

3) Oxygenases - oxidize a substrate by transferring the oxygen from molecular oxygen (02)
to it

4) Peroxidases - use hydrogen peroxide (H2O2) as optimal substrate

5) Hydroxylases - transfer hydroxyl group (-OH) to organic compounds

6) Reductases - catalyze reduction reactions

16

Enzymes catalase reactions by:

A. Increasing entropy of system
B. Increasing substrate energy
C. Altering reaction equilibrium
D. Decreasing free energy of activation

D. Decreasing free energy of activation

17

What is Km?

A. It refers to the substrate concentration at which a reaction is proceeding at half
maximum velocity (Vmax)
B. It indicates the capacity of the substrate to bind to the enzyme’s allosteric site
C. It refers to the rate of reaction when the substrate concentration is one-half the
maximum level
D. AOTA

A. It refers to the substrate concentration at which a reaction is proceeding at half
maximum velocity (Vmax)

The Michaelis constant Km is defined as the substrate concentration at 1/2 the maximum velocity.

18

Which tightly-bound co-enzyme functions as a prosthetic group?

A. Pyridoxal phosphate
B. Biotin
C. FMN
D. Co-enzyme A

C. FMN

Flavin mononucleotide (FMN), or riboflavin-5′-phosphate, is a biomolecule produced from riboflavin (vitamin B2) by the enzyme riboflavin kinase and functions as prosthetic group of various oxidoreductases

19

The pathway that generates the greatest amount of ATP?

A. Glycolysis
B. Oxidative phosphorylation
C. Citric acid cycle
D. Pentose phosphate pathway

B. Oxidative phosphorylation

- Glycolysis = 2 ATP
- Oxidative phosphorylation = 30-36 ATP
- Citric acid cycle = 2 ATP
- Pentose phosphate pathway = 0 ATP

20

Part of the enzyme with complex molecular structure that chemically facilitates the
conversion of substrate product:

A. Active site
B. Ligand site
C. Conversion site
D. Catalytic site

A. Active site (my answer)

D. Catalytic site (class)

* Active site - the region of an enzyme where substrate molecules bind and undergo a chemical reaction; made up of binding site and catalytic site

Ligand site
C. Conversion site

21

Which of the following best describes glycogenolysis:

A. Involves enzymes cleaving beta 1,4 glycosidic bonds
B. Requires a dual action enzyme alpha 1,4 glycosidase and transferase
C. Uses ATP to produce glucose 1-PO4
D. Requires inactivation of phosphorylase kinase
E. NOTA

E. NOTA

Answer should be NOTA. Glycogenolysis: involves cleaving alpha 1,4 glycosidic
bonds, requires a dual action enzyme alpha 1,6 glucosidase and transferase, uses inorganic
phosphate (Pi) to produce glucose 1-PO4, and requires activation of phosphorylase kinase.

22

Hydrolysis of lactose yields what combination of

A. Glucose and Fructose
B. Glucose and Galactose
C. Glucose and Glucose

B. Glucose and Galactose

A. Glucose and Fructose = sucrose
C. Glucose and Glucose = maltose

23

Three most common disaccharides:

Fructose
Galactose
Glucose
Lactose
Maltose
Sucrose

Lactose
Maltose
Sucrose

Fructose, Galactose, and Glucose are monosaccharides

24

Hydrolysis of maltose yields:

A. Glucose and Fructose
B. Glucose and Galactose
C. Glucose and Glucose

C. Glucose and Glucose

A. Glucose and Fructose = sucrose
B. Glucose and Galactose = lactose

25

Hydrolysis of sucrose yields:

A. Glucose and Fructose
B. Glucose and Galactose
C. Glucose and Glucose

A. Glucose and Fructose

B. Glucose and Galactose = lactose
C. Glucose and Glucose = maltose

26

4 Major Steps of Cellular Respiration

1) Glycolysis
2) Pyruvate Oxidation
3) Citric Acid Cycle (aka Krebs Cycle)
4) Oxidative Phosphorylation

27

What is the purpose of converting pyruvate to lactate in anaerobic glycolysis?

A. To regenerate NAD+
B. To prevent pyruvate from entering the citric acid cycle
C. To ferment pyruvate
D. To provide a pathway for gluconeogenesis

A. To regenerate NAD+

28

Which of the following inhibits the rate-limiting step in glycolysis?

A. Citrate
B. ATP
C. Glucagon
D. AOTA

D. AOTA

Citrate, ATP, and Glucagon all inhibit phosphofructokinase 1

29

The role of pentose phosphate pathway includes the following, EXCEPT:

A. Allows pathways for metabolism of unusual sugars
B. Synthesis of NADPH
C. Synthesis of ATP
D. Synthesis of Ribose 5-phosphate

C. Synthesis of ATP

PPP yields many sugars, ribose 5-phosphate, ribulose 5-phosphate, and CO2. Consumes 1 H20.

30

The Uronic Acid Pathway occurs in what part of the body?

A. Adipose Tissue
B. Adrenal glands
C. Liver
D. Kidneys

C. Liver

31

Which of the following best describes phospholipids?

A. Main lipid constituent of cell membranes
B. Polar ionic compounds made up of an alcohol that is attached to a glycerol or to a
sphingosine
C. Amphipatic in nature
D. AOTA

D. AOTA

32

What is the chemical formula of fatty acid at physiologic pH?

A. CH2(CH2)nCOO-
B. CH2(CH3)n
C. CH3(CH2)nCOOH
D. CHnCH3CH2

C. CH3(CH2)nCOOH

33

What phospholipid make up dipalmitoyl lecithin, the major constituent of lung
surfactant?

A. Phosphatidyl inositol
B. Phosphatidyl serine
C. Phosphatidyl ethanolamine
D. Phosphatidyl choline

D. Phosphatidyl choline

phosphatidylcholines are commonly called lecithins

34

Which of the following inhibit platelet aggregation?

A. Prostaglandin E2
B. Leukotrienes
C. Prostacyclin
D. Thromboxane

C. Prostacyclin

D. Thromboxane - promotes aggregation

35

What is the role of the enzyme aldolase in gluconeogenesis

A. It synthesizes 2 triose phosphates
B. It condenses 2 triose phosphates to form a 6-carbon compound
C. It converts aldoses to ketoses
D. It delivers adenosine triphosphate to the cytosol as a source of energy for
gluconeogenesis

B. It condenses 2 triose phosphates to form a 6-carbon compound

36

Why is gluconeogenesis not possible in skeletal muscles?

A. Skeletal muscles do not have the enzyme lactate dehydrogenase to convert
lactate to pyruvate
B. Skeletal muscles do not have mitochondria for oxaloacetate synthesis
C. Skeletal muscles do not have the enzyme glucose-6-phosphatase
D. Skeletal muscles are deficient in fructose-1,6-bisphosphatase, the rate-limiting enzyme of gluconeogenesis

C. Skeletal muscles do not have the enzyme glucose-6-phosphatase

37

What is the rate-limiting enzyme of fatty acid synthesis?

A. Fatty acid synthase
B. Acetyl-CoA carboxylase
C. HMG-CoA synthase
D. Citrate synthase

B. Acetyl-CoA carboxylase

38

What is the coenzyme of acetyl-CoA carboxylase?

A. Pyridoxine
B. Biotin
C. Thiamine
D. Lipoic acid

B. Biotin

39

The major pathway used to oxidize free fatty acids in humans is called the:

A. ω-oxidation
B. Peroxisomal oxidation
C. Alpha-oxidation
D. Beta-oxidation

D. Beta-oxidation

40

What apoprotein is the main protein marker of chylomicrons?

A. Apo A-1 - HDL
B. Apo B-100 - LDL
C. Apo B-48
D. ApoE

C. Apo B-48

41

This gangliosidosis presents with enlargement of the liver EXCEPT:

A. Metachromatic leukodystrophy
B. Niemann Pick Disease
C. Generalized gangliosidosis
D. Gaucher’s Disease

A. Metachromatic leukodystrophy (Harper pg 251)

A. Metachromatic leukodystrophy - abnormal muscle movement, behavior problems,
decreased mental function
B. Niemann Pick Disease - difficulty moving limbs that may lead to unsteady gait,
clumsiness, walking problems, and hepatosplenomegaly
C. Generalized gangliosidosis - neurodegeneration, hepatosplenomegaly, joint stiffness,
muscle weakness
D. Gaucher’s Disease - hepatosplenomegaly, anemia, thrombocytopenia

42

This cerebrosidosis is due to a deficiency of the enzyme arylsulfatase A:

A. Metachromatic leukodystrophy
B. Niemann Pick Disease
C. Generalized gangliosidosis
D. Gaucher’s Disease

A. Metachromatic leukodystrophy

B. Niemann Pick Disease - mutations in the SMPD1 gene which provides instructions for
producing an enzyme sphingomyelinase
C. Generalized gangliosidosis - mutations in the GLB1 gene which may lower or eliminate
the activity of β-galactosidase
D. Gaucher’s Disease - glucocerebrosidase

43

How many molecules of Acetyl-CoA are needed to synthesize one molecule of HMG-CoA?

A. One
B. Two
C. Three
D. Four

C. Three

44

Conversion of HMG-CoA to Mevalonate requires:

A. Thiolase
B. HMG-CoA synthase
C. Mevalonate synthase
D. HMG-CoA reductase

D. HMG-CoA reductase

45

Class of drugs acting as HMG-CoA Reductase Inhibitors, which acts well on lowering
cholesterol in the body:

A. Statins
B. Cholestyramine
C. Plant sterols
D. Fiber

A. Statins

46

Which of the following cause the unwinding of the DNA double helix?

A. DNA polymerase
B. DNA helicase
C. RNA primer
D. Primosome

B. DNA helicase

A. DNA polymerase - Deoxynucleotide polymerization
C. RNA primer -
D. Primosome

47

A replication fork is:

A. Only seen in bacterial cells
B. A Y-shaped structure where both DNA strands are replicated simultaneously
C. A site where one DNA strand serves as a template, but the other strand is not replicated
D. Is created by the action of RNA polymerase

B. A Y-shaped structure where both DNA strands are replicated simultaneously

48

Okazaki fragments are joined together by:

A. RNA polymerase
B. DNA ligase
C. DNA polymerase
D. RNA ligase

B. DNA ligase

49

The genetic code is said to be unambiguous because:

A. A specific codon always codes for the same amino acid
B. The genetic code has been considered from the very early stages of evolution
C. All amino acids always have only one triplet codon
D. The code is always read from a fixed starting point

A. A specific codon always codes for the same amino acid - “The genetic code is
unambiguous: each codon specifies one amino acid only.”

50

Prokaryotic transcription promoters are:

A. Can have variable location
B. Responsible for both initiation and termination
C. Located downstream of the gene
D. Located upstream of the gene

D. Located upstream of the gene

51

It occurs primarily during replication

A. Genetic mutation
B. Genetic regulation
C. Gene expression
D. AOTA

D. AOTA

52

Polymerase involved in the synthesis of hnRNA:

A. Pol I
B. Pol II
C. Pol III
D. AOTA

B. Pol II

A. Pol I - RNA primers are removed and replaced with DNA
C. Pol III - extends the primers, adding on to the 3' end, to make the bulk of the new DNA

53

Known as a start codon:

A. AAA
B. AUC
C. AUA
D. AUG

D. AUG

54

The defective gene in Huntington’s Disease exhibit excessive repeats of:

A. AAU
B. AUG
C. CAG
D. TAT

C. CAG

55

Which of the following can cause frameshift mutations?

A. Substitution
B. Insertion
C. Both A and B
D. Neither A nor B

B. Insertion

56

Makes DNA repair possible

A. Proofreading is done only once
B. Genetic information is “backed up” on existing RNA
C. Redundancy of information inherent in the double helix
D. Copies of the gene exists somewhere else in the genome

C. Redundancy of information inherent in the double helix

57

The following causes base modification, strand breaks, cross-linkage between bases on opposite strands or between DNA and protein, and numerous other defects:

A. Ionizing radiation
B. Cancer chemotherapeutic agents
C. A variety of chemicals in the environment
D. AOTA

D. AOTA

58

Pernicious anemia due to a lack of intrinsic factor is a classic consequence of a deficiency in:

A. Cobalamin
B. Folic acid
C. Biotin
D. Riboflavin

A. Cobalamin - Vitamin B12; Coenzyme in transfer of one-carbon fragments and metabolism of folic acid
Pernicious anemia = megaloblastic anemia with degeneration of the spinal cord

Others
B. Folic acid - B6: Megaloblastic anemia
C. Biotin - Vitamin H: Impaired fat and carbohydrate metabolism, dermatitis
D. Riboflavin - Lesions of corner of mouth, lips, and tongue, seborrheic dermatitis

59

Lipid soluble vitamins:

A - retinol, beta carotine
D - calciferol
E - tocopherols
K - phylloquinone

60

Which is not an essential amino acid?

E. Alanine
F. Valine
G. Lysine
H. Methionine

E. Alanine

61

Name essential amino acids

P.V.T.
P = Phenylalanine
V - Valine
T - Threonine

T.I.M.
T - Tryptophan
I - Isoleucine
M - Methionine

H.A.L.L.
H - Histidine
A - Arginine
L - Leucine
L - Lysine

62

Which of the following hormones pass through the plasma membrane and act by binding to an intracellular receptor?

A. Epinephrine
B. Testosterone
C. Glucagons D. Oxytocin

B. Testosterone - it is a hormone

63

Which of the following lipids is most readily absorbed in the intestine?

A. Cholesteryl esters
B. Triacylglycerols
C. Small and medium chain fatty acids
D. Very low density lipoproteins

C. Small and medium chain fatty acids

Others
A. Cholesteryl esters
B. Triacylglycerols
D. Very low density lipoproteins

64

Which of the following contribute to the amino acid pool?

A. Proteolysis of body protein
B. Dietary absorption of amino acids
C. Both A and B
D. Neither A nor B

C. Both A and B

65

Which amino acid is the precursor of neurotransmitter serotonin?

A. Tryptophan
B. Tyrosine
C. Phenylalanine
D. Methionine

A. Tryptophan

66

Which of the following statements about amino acids is true?

A. Amino acids contain an amino group and a carboxylic group
B. D-amino acids are incorporated into tissue proteins by the protein-synthesizing machinery of the cell
C. Proline is an alpha-amino acid
D. AOTA

A. Amino acids contain an amino group and a carboxylic group

Proline is an IMINO acid. D amino acids are NOT incorporated in proteins

67

Which of the following statements best describes the structure of glucose?

A. Majority of glucose molecules in solution exist in the furanose form
B. It is considered as a ketose
C. The C1 carbon is the anomeric carbon
D. It has only two asymmetric carbons

C. The C1 carbon is the anomeric carbon

68

Which of the following conditions promotes ketogenesis?

A. Low levels of circulating fatty acids
B. Excess production of insulin
C. Increased levels of Acetyl coA
D. Accelerated gluconeogenesis

C. Increased levels of Acetyl coA

Ketones are produced acetyl coA

69

Which Immunoglobulin isotype increases during parasitic infections?

A. IgA
B. IgD
C. IgE
D. IgG

C. IgE

70

Which of the following bonds is the strongest due to sharing of electrons?

A. Ionic bonds
B. Covalent bonds
C. Salt linkages
D. Van der Waals forces

B. Covalent bonds

71

Which class of enzymes adds water across a bond, hydrolyzing it?

A. Isomerases
B. Lysases
C. Hydrolases
D. Ligases

C. Hydrolases


A. Isomerases - convert a molecule from one isomer to another
B. Lysases - catalyzes the breaking (an "elimination" reaction) of various chemical bonds by means other than hydrolysis (a "substitution" reaction) and oxidation, often forming a new double bond or a new ring structure
D. Ligases - joining of two large molecules by forming a new chemical bond

72

This is a mixed function oxidase:

A. CYP450
B. Superoxide dismutase
C. Adenylyl kinase
D. Xanthine oxidase

A. CYP450

73

How many high energy bonds are present in ADP?

A. 1
B. 2
C. 3
D. None

B. 2

*ATP is hydrolyzed to ADP and inorganic phosphate when it is in equilibrium with water.
In ATP, there are three phosphate groups with two high-energy bonds

74

The conversion of an aldehyde to a carboxylic acid is an example of

A. Oxidation
B. Reduction
C. Hydration
D. Dehydration

A. Oxidation

75

Beta oxidation pathway is an example of

A. Fat catabolism
B. Fat anabolism
C. Carbohydrate anabolism
D. Carbohydrate catabolism

A. Fat catabolism

Beta oxidation is the process of removing acetyl CoA fragments from the ends of fatty acids.

76

Why is the Krebs cycle an amphibolic pathway?

A. It replenishes intermediates needed for glucose synthesis
B. Its substrates are all soluble in aqueous solution
C. Acts as a carrier of carboxyl groups from cytoplasm to mitochondria
D. It is involved in both synthesis and breakdown of essential biomolecules

D. It is involved in both synthesis and breakdown of essential biomolecules

77

Transamination of glutamic acid will form this citric acid cycle intermediate?

A. Pyruvate
B. Succinate
C. Alpha ketoglutarate
D. Oxaloacetate

C. Alpha ketoglutarate *contains 5 carbon molecules; formed from isocitrate by the enzyme
isocitrate dehydrogenase; this yields 1 NADH and 1 CO2


A. Pyruvate *contains 3 carbon molecules; formed from glucose (contains 6 carbons)
B. Succinate *contains 4 carbon molecules; formed from Succinyl CoA by the enzyme Succinate thiokinase aka Succinyl CoA synthetase; yields 1 GTP (1 GTP = 1 ATP)
D. Oxaloacetate *contains 4 carbon molecules; formed from Malate by the enzyme malate dehydrogenase; yields 1 NADH

78

The urea cycle takes place

a. In the cytosol and mitochondria of all the body tissues that have a nucleus
b. In the kidney where urea is excreted in the urine
c. In the liver cytosol and mitochondria
d. In the mitochondria golgi complex and ER of hepatic sinusoids

c. In the liver cytosol and mitochondria

79

How many phosphates are used in the formation of urea?

A. 1
B. 2
C. 3
D. 4

D. 4 *Four moles of high energy phosphate bonds are released in the synthesis of 1 mole of urea.

80

What is the difference between DNA and RNA synthesis?

A. There is no proofreading function in DNA synthesis
B. The entire genome is not copied during RNA synthesis
C. DNA is read in a 5’—3’ direction in DNA synthesis but not in RNA synthesis
D. The strands form hydrogen bonds with loops or turns

B. The entire genome is not copied during RNA synthesis

81

PRPP act as substrate for:

A. Purine synthesis
B. Pyrimidine synthesis
C. Both purine and pyrimidine synthesis
D. Neither purine and pyrimidine synthesis

C. Both purine and pyrimidine synthesis

82

True of deoxyribonucleotide synthesis:

A. It is catalyzed by an enzyme that causes reduction of the substrate
B. The ultimate source of electrons for its synthesis is NADPH
C. It is synthesized from ribonucleotide
D. All of the above

D. All of the above

83

What lipoprotein particles are the lowest in density and the largest in size?

A. Chylomicron
B. VLDL
C. LDL
D. HDL

A. Chylomicron

Greatest to lowest density: HHDL > LDL > IDL > VLDL > Chylomicrons

84

The following substances compose the hydrophilic coating of lipoproteins, EXCEPT:

A. Cholesteryl Ester
B. Phospholipid
C. Protein
D. Cholesterol

A. Cholesteryl Ester

85

What enzyme catalyzes the hydrolysis of triglyceride and cholesteryl ester in lysosomes?

A. LCAT
B. Lipoprotein lipase
C. Hepatic lipase
D. Acid lipase

A. LCAT
B. Lipoprotein lipase
C. Hepatic lipase
D. Acid lipase

86

Which is the main reason why fats are better storage form of energy than carbohydrates?

A. Carbohydrates are more hydrophilic than fats.
B. Fats are more reduced than carbohydrates.
C. Fatty acids can form triacylglycerols and chylomicron.
D. The liver has a preferential metabolism for fats.

B. Fats are more reduced than carbohydrates.

87

What do you call hormones that are transported by blood to their target cells which are usually far away from the glands that produce

A. Autocrine hormones
B. Endocrine hormones
C. Exocrine hormones
D. Paracrine hormones

B. Endocrine hormones

88

Which of the following hormones pass through the plasma membrane and act by binding to an intracellular receptor?

A. Epinephrine
B. Testosterone
C. Glucagon
D. Oxytocin

B. Testosterone

89

What are the final product of fatty acid synthesis?

A. Cholesterol
B. Acetic acid
C. Palmitic acid
D. Propionyl-CoA

C. Palmitic acid

90

What is the correct sequence of reactions catalyzed by fatty acid synthase?

A. Reduction, Condensation, Dehydration, Reduction
B. Condensation, Reduction, Dehydration, Reduction
C. Dehydration, Reduction, Condensation, Reduction
D. Condensation, Reduction, Condensation, Dehydration

B. Condensation, Reduction, Dehydration, Reduction

CRDR
Fatty acid synthase (FAS) carries out the chain elongation steps of fatty acid synthesis which involves the following steps: CRDR - Condensation, Reduction, Dehydration, Reduction

91

Which of the following activates fatty acid synthesis?

A. Palmitoyl CoA
B. Malonyl CoA
C. Citrate
D. Oxaloacetate

B. Malonyl CoA

Formation of Malonyl CoA is the rate-limiting step for fatty acid synthesis, because it has no other role other than serving as precursor to fatty acid synthesis.

92

What do you call the bond between glycerol and a fatty acid?

A. Hydrogen
B. Ionic
C. Esther
D. Ester

D. Ester

In a fat molecule (triglyceride), the fatty acids are attached to each of the three carbons of glycerol molecule with a covalent bond called an ester bond through the oxygen atom.

93

Which of the following inhibits phospholipase A2?

A. Prednisone
B. Ibuprofen
C. Aspirin
D. Celecoxib

A. Prednisone

Prednisone is a synthetic glucocorticoid that inhibits phospholipase A2. Ibuprofen, Aspirin, and Celecoxib are NSAIDs. Ibuprofen and Aspirin inhibits COX enzyme. Celecoxib specifically inhibits COX-2 isoenzyme.

94

Which of the following can yield LTA4?

A. PGH2
B. TXA2
C. HPETE
D. PGD2

C. HPETE

Leukotriene A4 (LTA4) is a product of hydroperoxyeicosatetranoic acid (HPETE) in the lipoxygenase pathway. PGH2, tXA2, and PGD2 are found in the cyclooxygenase pathway.

95

The following are coenzymes that transfers H+, except:

A. Coenzyme Q
B. Folate coenzymes
C. Thiamine pyrophosphate
D. Sugar phosphate

C. Thiamine pyrophosphate

Thiamine pyrophosphate transfers aldehyde groups.

96

Which of the following catalyze the reverse reaction that splits the aldol fructose 1,6 bisphosphate into the triose phosphate dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate?

A. Decarboxylases
B. Carboxylases
C. Synthases
D. Aldolases

D. Aldolases

The reaction above is a retro-aldol reaction in glycolysis catalyzed by then enzyme fructose 1,6 bisphosphate aldolase.

97

The following are true of steroids, except:

A. Cyclopentanoperhydrophenanthrene
B. Has four fused rings with carbons numbered in sequence
C. Sterols are steroids with 8-10 carbon atoms in the side chain and a fatty acid attached to carbon 3
D. Much of the plasma cholesterol is in esterified form

C. Sterols are steroids with 8-10 carbon atoms in the side chain and a fatty acid attached to carbon 3

Sterols are steroids with 8-10 carbon atoms in the side chain and an alcohol group attached to carbon 3

98

Palmitic acid has 16 carbon atoms with:

A. No double bonds
B. One double bond
C. Two double bonds
D. Four double bonds

A. No double bonds

Palmitic acid is a saturated fatty acid. Saturated fatty acids do not contain double bonds. Other examples are: stearic and lauric acid. In contrast, unsaturated fatty acids contain double bonds (eg: palmitoleic and linoleic acid)

99

Which of the following gives rise to cardiolipin in the mitochondria and the only human phosphoglyceride that is antigenic?

A. Phosphatidylethanolamine
B. Phosphatidylinositol
C. Phosphatidylglycerol
D. Phosphatidylcholine

C. Phosphatidylglycerol

Two phosphatidylglycerols form cardiolipin.

100

Compounds having the same structural formula but differing in spatial configuration are known as:

A. Anomers
B. Stereoisomers
C. Epimers
D. Optical isomers

B. Stereoisomers

Isomers are compounds with the same chemical formula but different structural formulas. There are two types of isomers:
1. Structural isomers - isomers having identical molecular formulas but differing in the order in which the individual atoms are connected.
2. Stereoisomers - the isomers have the same molecular and structural formula but differ in the spatial arrangement of the atoms in the molecule
Optical isomers or enantiomers are types of stereoisomers that are mirror images.
Epimers are stereisomers that differ only at one position(eg: glucose and galactose) Anomers are epimers at the hemiacetal/acetal carbon in a cyclic saccharide (eg: a and B forms)

101

In glucose, the orientation of the -H and - OH around the carbon atom 5 adjacent to the terminal primary alcohol carbon

A. Dextro or levorotatory
B. Epimers
C. D or L series
D. A & b anomers

A. Dextro or levorotatory

102

A patient presents with dermatitis, diarrhea, dementia and stomatitis. He is probably deficient in :

A. Thiamine
B. Niacin
C. Vitamin B12
D. Pantothenic acid

B. Niacin -- Niacin (Vit B3) - Symptoms of pellagra are known as the 'three Ds': dermatitis, diarrhoea and dementia.

Deficiencies and associated conditions:
Thiamine (Vit B1) - Beri-beri
Vitamin B12 (cobalamin) - Pernicous anemia
Pantothenic acid (Vit B6) - Deficiency is rare

103

Both Beri-beri and Wernicke-Korsakoff Syndrome can be reversed by administering

A. Vitamin B1
B. Vitamin B3
C. Vitamin B12
D. Vitamin B5

A. Vitamin B1

104

A deficiency of vitamin B12 causes

A. Cheilosis
B. Beri-beri
C. Pernicious anemia
D. Scurvy

C. Pernicious anemia

Cheilosis - Vit B2
Beri-beri - Vit B1
Pernicious anemia - Vit B12
Scurvy - Vit C

105

Which cytochrome catalyzes the removal of hydrogen from a substrate using oxygen as a hydrogen acceptor

A. Cytochrome a3
B. Cytochrome b
C. Cytochrome c
D. Cytochrome d-protein

A. Cytochrome a3- catalyzes the removal of hydrogen from a substrate in the form of h20 and h202 using oxygen as a hydrogen acceptor


B. Cytochrome b-Cytochrome b is a protein found in the mitochondria of eukaryotic cells. It functions as part of the electron transport chain
C. Cytochrome c -highly water-soluble, unlike other cytochromes, and is an essential component of the electron transport chain, where it carries one electron. It is capable of undergoing oxidation and reduction, but does not bind oxygen.
D. Cytochrome d-protein that catalyses a chemical reaction. Cytochrome d is also known as cytochrome/heme a2. It is found in plenty of aerobic bacteria, especially when it has grown with a limited oxygen supply. The bacteria species in which it is more commonly found are Escherichia coli and Aerobacter aerogenes.[1]

106

This is a mixed function oxidase

A. Cytochrome p450
B. Superoxidase dismutase
C. Adenylyl kinase
D. Xanthine oxidase

A. Cytochrome p450


B. Superoxidase dismutase- enzyme that helps break down potentially harmful oxygen molecules in cells, which might prevent damage to tissues.
C. Adenylyl kinase - 2.7.4.3) (also known as ADK or myokinase) is a phosphotransferase enzyme that catalyzes the interconversion of adenine nucleotides (ATP, ADP, and AMP). By constantly monitoring phosphate nucleotide levels inside the cell, ADK plays an important role in cellular energy homeostasis.
D. Xanthine oxidase- a form of xanthine oxidoreductase, a type of enzyme that generates reactive oxygen species.

107

The krebs cycle intermediate is the entry point for the breakdown of propionic acid. It is also used for heme synthesis

A. Succinyl-CoA
B. Fumarate
C. Malate
D. Oxaloacetate

A. Succinyl-CoA

108

Molecular oxygen is a good oxidant because

A. It is highly electronegative
B. It contains a complete set of electron in its outermost shell
C. It has a low affinity for electrons
D. It is an inert gas

A. It is highly electronegative

109

The conjugate base of an acid is produced by:

A. Adding a proton to the acid
B. Adding an electron to the acid
C. Removing a proton from the acid
D. Removing an electron from the acid

C. Removing a proton from the acid

Conjugate ACID formed by the reception of a proton (H+) by a base

Conjugate BASE formed by the removal of a proton from an acid

110

The rate-limiting step in fatty acid synthesis is:

A. Condensation of acetyl coa and malonyl coa
B. The reaction catalyzed by acetyl coa carboxylase
C. Formation of acetyl coa from acetate
D. Formation of malonyl coa from malonate and coenzyme

B. The reaction catalyzed by acetyl coa carboxylase

111

Which of the following is a ketone body?

A. Betahydroxybutyrate
B. Acetone
C. Acetoacetate
D. A&Conly
E. AOTA

E. AOTA

112

Which of the following amino acids contain a sulfhydryl group?

A. Cysteine
B. Isoleucine
C. Phenylalanine
D. Proline
E. Glycine

A. Cysteine

113

All the carbon atoms of cholesterol are derived from which of the following?

A. NADPH
B. Acetate
C. Glycerol
D. Glucose6phosphate
E. Pyruvate

B. Acetate

114

Which of the following BEST describes a peptide bond?

A. Consideredahydrophobicbond
B. Generallyacisbond
C. Nonrigidandflexible
D. Partial double bond character

D. Partial double bond character

115

Which of the following statements is TRUE about beta bends?

A. Composed of 5 amino acids
B. Proline causes a “kink” in the polypeptide chain
C. Are stabilized by covalent bonds
D. Usually found at the interior of the protein molecule
E. AOTA

B. Proline causes a “kink” in the polypeptide chain

Others:
A. Composed of 5 amino acids - shortest is 6 amino acids
C. Are stabilized by covalent bonds -Beta bends are stabilized by hydrogen bonds not covalent bonds.


116

Interactions stabilizing tertiary structure of proteins involve which of the following?

A. Disulfidebonds
B. Hydrophobicbonds
C. Hydrogenbonds
D. ProtoporphyrinX & protoporphyrin
E. Ferrousiron & protoporphyrinXII

A. Disulfidebonds
B. Hydrophobicbonds
C. Hydrogenbonds

117

Heme is a complex of which of the following?

A. Ferrous & ferricirons
B. Ferric iron & protoporphyrin X
C. Ferrous iron & protoporphyrin IX
D. Protoporphyrin X & protoporphyrin
E. Ferrous iron & protoporphyrin XII

C. Ferrous iron & protoporphyrin IX

118

Which of the following describes the oxygen dissociation curve of hemoglobin?

A. Hyperbolic shape
B. Shows cooperative binding
C. Reflects that hemoglobin binds only to one oxygen molecule
D. Shows higher oxygen affinity than myoglobin
E. AOTA

B. Shows cooperative binding

119

Which of the following statements is TRUE regarding sickle cell disease?

A. It is a point mutation in the Beta globin gene
B. It is characterized by a life long pain “crises” and hemolytic anemia
C. In the Beta globin chain, glutamate at position 6 is replaced with valine
D. A & C only
E. AOTA

E. AOTA

A. It is a point mutation in the Beta globin gene- mutation from GAG to GTG
B. It is characterized by a life long pain “crises” andnhemolyticnanemian-nsee sickle cell crisis
C. In the Beta globin chain, glutamate at position 6 is replaced with valine

120

Which of the following is the MOST abundant protein in the human body?

A. Elastin
B. Fibrin
C. Collagen
D. Desmosine
E. Albumin

C. Collagen

121

Which of the following statements is TRUE about elastin?

A. High-tensile strength
B. Rubber like properties
C. Found in lungs and walls of large arteries
D. A & C only
E. All of the above

E. All of the above

122

Emphysema is MOST likely associated with which of the following?

A. Ehler-Danlos syndrome
B. a1-antitrypsin deficiency
C. Osteogenesis imperfecta
D. Multiple sclerosis
E. Hunter’s syndrome

B. a1-antitrypsin deficiency

123

Which of the following groups of enzymes catalyze the cleavage of bonds by the addition of water?

A. Oxidoreductases
B. Transferases
C. Hydrolases
D. Lyases
E. Catalases

C. Hydrolases

124

Which of the following will BEST describe the reaction of the value of Ea is large?

A. The rate of forward reaction will be fast and the value of k1 will be large
B. The rate of reverse reaction will be fast and the value of k1 will be large
C. The rate of the reverse reaction will be slow and the value of k1 will be large
D. The rate of forward reaction will be slow and the value of k1 will be small
E. The rate of foward reaction will be equa lto zero

D. The rate of forward reaction will be slow and the value of k1 will be small

125

15. Which of the following correctly describes non-competitive inhibition?

A. Substrate concentration is increased
B. Km is unchanged
C. Vmax is greater than normal
D. Inhibitor and substrate bind at the same site on the enzyme
E. All of the above

E. All of the above

126

16. Which of the following statements is True about G?

A. It is the energy available to do work
B. It approaches zero as the reaction proceeds to equilibrium
C. It predicts whether a reaction is favorable
D. A & Conly
E. All of the above

E. All of the above

127

What is the final electron acceptor in the electron transport chain?

A. Cytochrome a+a3
B. Molecular oxygen
C. Coenzyme Q
D. Complex III
E. Complex IV

B. Molecular oxygen

128

Which of the following enzymes is involved in the formation of ATP via oxidative phosphorylation?

A. ADP reductase
B. ATP oxidoreductase
C. ADP hydrolase
D. ATP synthesis
E. ADP synthesis

D. ATP synthesis

129

Carbohydrates that differ in configuration around only one specific carbon atom are known as which of the following?

A. Epimers
B. Enantiomers
C. Anomers
D. Isomers
E. Stereoisomers

A. Epimers


B. Enantiomers - molecules are mirror image
C. Anomers - an epimer at the hemiacetal/acetal carbon in a cyclic saccharide
D. Isomers - compounds with the same formula but a different arrangement of atoms in the molecule and different properties
E. Stereoisomers - differing only in the spatial arrangement of their atoms

130

The disaccharide lactose is a combination of which of the following monosaccharide?

A. Glucose + Fructose
B. Glucose + Glucose
C. Glucose + galactose
D. Glucose + Mannose
E. Glucose + Maltose

C. Glucose+galactose

131

21. The inability of humans to digest cellulose is because humans lack the enzyme that can digest which type of bonds of cellulose?

A. B (1-4) glycosidic bonds
B. A (1-6) glycosidic bonds
C. B (1-6) glycosidic bonds
D. A (1-4) glycosidic bonds
E. A (4-4) glycosidic bonds

A. B (1-4) glycosidic bonds

132

Which enzyme catalyzes substrate-level phosphorylation in glycolysis?

A. Hexokinase
B. PFK1
C. Glyceraldehyde-3-phosphate dehydrogenase
D. Phosphoglycerate kinase
E. Glucokinase

D. Phosphoglycerate kinase

133

The activity of which of the following enzyme of glycolysis is enhanced by insulin?

A. Glucokinase
B. PFK1
C. Pyruvate kinase
D. A & C only
E. All of the above

A. Glucokinase

134

Pyruvate may be converted to which of the following?

A. Acetyl CoA
B. Oxaloacetate
C. Alanine
D. A & C only
E. All of the above

D. A & C only

135

Which is a product of pyruvate dehydrogenase complex reaction?

A. AcetylCoA
B. Oxygen
C. Carbonmonoxide
D. FADH2
E. NADPH

A. AcetylCoA

136

Which of the following enzymes catalyzes substrate-level phosphorylation in Kreb’s Cycle?

A. Fumarase
B. Succinate dehydrogenase
C. Succinate thiokinase
D. Isocitrate dehydrogenase
E. Aconitase

C. Succinate thiokinase

137

What is the number of ATPs produced from one turn of the Kreb’s cycle?

A. 10
B. 12
C. 24
D. 137
E. 147

A. 10

138

Which of the following substrates may serve as a substrate for gluconeogenesis?

A. Glycerol
B. Lactate
C. Amino acids
D. A & C only
E. All of the above

E. All of the above

139

Which of the following factors is required in the carboxylation of pyruvate during gluconeogenesis?

A. Thiamine
B. Pyruvate dehydrogenase
C. Biotin
D. GTP
E. Glycine

C. Biotin

140

Glucagon stimulates gluconeogenesis by which of the following mechanisms?

A. Changes in the allosteric effectors
B. Covalent modification of enzyme activity
C. Induction of enzyme synthesis
D. A & C only
E. All of the above

B. Covalent modification of enzyme activity (by decreasing levels off ructose 2,6 bisphosphate)

141

Which of the following BEST describes the structure of glycogen?

A. It is branched-chain heteropolysaccharide
B. Exclusively made of a-D-glucose
C. The primary glycosidic bond is an a(1-4) linkage
D. It is an aliphatic homopolysaccharide
E. a (1-4) linkage at branch points

C. The primary glycosidic bond is an a(1-4) linkage

142

Which of the following is the rate limiting enzyme in glycogenesis?

A. Glycogen synthase
B. Glycogen phosphorylase
C. Glucosyl 4:6 transferase
D. Glucosyl 4:4 transferase
E. Glucosyl 6:6 transferase

A. Glycogen synthase

143

What is the enzyme deficiency in the glycogen storage disease called von Gierke’s ?

A. Glycogen phosphorylase
B. Myophosphorylase
C. Lysosomal a(1-4) glucosidase
D. Glucose-6-phosphatase
E. Lysosomal a(1-6) glucosidase

D. Glucose-6-phosphatase

144

Hereditary fructose intolerance is due to a deficiency of which of the following enzymes?

A. Uridyltransferase
B. Galactokinase
C. Aldose reductase
D. UDP-hexose-4-epimerase
E. Uridylkinase

C. Aldose reductase (aldolase b)

145

Classic galactosemia is due to a deficiency of which of the following enzymes?

A. Uridyltransferase
B. Galactokinase
C. Aldose reductase
D. UDP-hexose-4-epimerase
E. Uridylkinase

A. Uridyltransferase- converts galactose to glucose


Other
C. Aldose reductase - converts galactose to galactitol in the lens of the eyes

146

Which of the following codons of the genetic code is a stop codon?

A. AUG
B. UAG
C. GUC
D. CUG
E. All of the above

B. UAG - along with UAA and UGA

147

Which of the following enzymes catalyzes the rate limiting step of the pentose phosphate pathway ?

A. Glucose 6 phosphate dehydrogenase
B. 6 phosphogluconolactone hydrolase C. 6 phosphogluconate dehydrogenase D. Transketolase
E. Transaldolase

A. Glucose 6 phosphate dehydrogenase

148

38. NADPH is a product of pentose phosphate pathway that may be used in which of the following?

A. Reductive biosynthesis
B. Cytochrome P450 mono oxygenase system
C. Reduction of hydrogen peroxide
D. A&Conly
E. AOTA

E. AOTA

Functions of NADPH (Lippincott)
● Reductive biosynthesis
● Reduction of hydrogen peroxide
● Antioxidant chemicals
● Cytochrome p450 monooxygenase system
● Vitamin D3 to its active form
● Phagocytosis of WBC
● Synthesis of Nitric Oxide

149

Which of the following is a precipitating factor in glucose 6 phosphate dehydrogenase deficiency (G6PD)?

A. Oxidant like chloramphenicol
B. Antimalarial drugs like primaquine
C. Infection
D. A & C only
E. AOTA

E. AOTA

150

Which of the following is the final degradation product of purines in humans?

A. Urine
B. Urea
C. Urate
D. Uridine 5’ monophosphate
E. Uric acid

E. Uric acid

For other mammals, allantoin is final product because of the enzyme uricase , which converts uric acid to allantoin. Humans and other primates have no uricase.

151

Hurler’s syndrome is characterized by a deficiency of which of the following enzymes?

A. Iduronate sulfatase
B. Beta glucoronidase
C. Heparan sulfamisade
D. Alpha L iduronidase



43. Glycerol that is released from triacylglycerol is used exclusively by the:
A. Liver
B. Pancreas C. Muscle D. Brain
E. Kidneys
Fed state: used for re esterification of FFA to TAG or as a substrate for gluconeogenesis in the liver
Fasting state: used as a substrate for gluconeogenesis in the liver and kidneys

D. Alpha L iduronidase

152

Which of the following is a characteristic of the genetic code?

A. Ambiguous
B. Universal
C. Degenerate
D. Overlapping
E. All of the above

B. Universal
C. Degenerate

Genetic code:
- Degenerate or redundant - Unambiguous
- Universal (almost, with very few exceptions)
- Nonoverlapping, commaless

153

Glycerol that is released from triacylglycerol is used exclusively by the:

A. Liver
B. Pancreas
C. Muscle
D. Brain
E. Kidneys

A. Liver

Fed state: used for re esterification of FFA to TAG or as a substrate for gluconeogenesis in the liver

Fasting state: used as a substrate for gluconeogenesis in the liver and kidneys

154

Which of the following statements is TRUE regarding the fate of the free fatty acids from the hydrolysis of triacylglycerol?

A. They enter the adjacent muscle cells
B. They enter the adjacent adipocytes
C. They bind with albumin in the serum
D. A & C only
E. All of the above

E. All of the above

155

Which enzyme catalyzes the rate limiting step in fatty acid synthesis?

A. Pyruvate caboxylase
B. Acetyl CoA carboxylase
C. Fatty acid synthetase
D. ATP synthase
E. Fatty acyl CoA synthase

B. Acetyl CoA carboxylase

156

Which of the following enzymes of the fatty acid synthase complex releases the final product of the Lynen cycle?

A. Acetyl CoA ACP acetyltransacyclase
B. Malonyl CoA ACP transacyclase
C. 3 Ketoacetyl ACP reductase
D. Palmitoyl thioesteraase
E. Acetyl CoA carboxylase

E. Acetyl CoA carboxylase?

157

Which pathway in the MAJOR supplier of NADPH for fatty acid synthesis?

A. Hexose monophosphate shunt
B. Glycolysis
C. Gluconeogenesis
D. Glycogenolysis
E. Fatty acid synthesis

A. Hexose monophosphate shunt (this is also known as Pentose Phosphate Pathway. Generates 2 NADPH)

158

What is the storage form of fats in the adipose tissues?

A. Cholesterolesters
B. Cholesterols
C. Triacylglycerol
D. Glycerol 3 phosphate

C. Triacylglycerol

159

Which vitamin will MOST likely manifest night blindness as one of the earliest signs of its deficiency?

A. Vit A
B. Vit D
C. VitE
D. VitK
E. VitB6

A. Vit A


Others: B.
Vit D - rickets (children) & orosteomalacia (adults)
C. VitE - hemolytic anemia, degenerative changes in muscle, sterility
D. VitK - hemorrhagic disease of the new born, biliary disease, anemia
E. VitB

160

Which of the following vitamins is implicated in Wernicke-Korsakoff syndrome?

A. Thiamine
B. Folate
C. Pyridoxine
D. Niacin
E. Biotin

A. Thiamine

161

In Embden-Meyerhoff pathway, 2-phosphoglycerate is converted to:

A. Phosphoenolpyruvate
B. Enolpyruvate
C. Dihydroxyacetone PO 4 (DHAP)
D. 1,3 bisphosphoglycerate

A. Phosphoenolpyruvate

162

An anaplerotic reaction which sustains the availability of oxaloacetate is the carboxylation of:

A. Glutamate
B. Pyruvate
C. Citrate
D. Succinate

B. Pyruvate

163

Specific test for ketohexoses:

A. Seliwanoff’s test
B. Osazone test
C. Molisch test
D. NOTA

A. Seliwanoff’s test

Other
B. Osazone test-for identification of sugars
C. Molisch test-for presence of carbohydrates

164

Two important byproducts of HMP shunt are:

A. NADH and pentose sugars
B. NADPH and pentose sugars
C. Pentose sugars and 4-membered sugars
D. Pentose sugars and sedoheptulose

B. NADPH and pentose sugars

165

Pyruvate dehydrogenase complex and alpha-ketoglutarate dehydrogenase complex require the following for their oxidative decarboxylation:

A. COASH and Lipoic acid
B. NAD+ and FAD
C. COASH and TPP
D. COASH, TPP, NAD+, FAD, Lipoate

D. COASH, TPP, NAD+, FAD, Lipoate

166

The four-membered aldose sugar phosphate formed in HMP shunt pathway is:

A. Xylulose PO 4
B. Erythrulose PO 4
C. Erythrose PO 4
D. Ribulose PO 4

D. Ribulose PO 4

Ribonucleic acid

167

Cane sugar (sucrose) injected into blood is:

A. Changed to fructose
B. Changed to glucose
C. Undergoes no significant change
D. Change to glucose and fructose

C. Undergoes no significant change - sucrose is a disaccharide (glucose + fructose) which
needs to be broken down first into monosaccharides before it is absorbed into the bloodstream.

168

Pentose production is increased in:

A. HMP shunt
B. Uronic acid pathway
C. Embden-Meyerhoff pathway
D. TCA cycle

A. HMP shunt

169

Conversion of alanine to carbohydrate is termed:

A. Glycogenesis
B. Gluconeogenesi
C. Glycogenolysis
D. Photosynthesis

B. Gluconeogenesis- generation of glucose from non-carbohydrate substrates, such as
glucogenic amino acids and glycerol.

Ketogenic AND glucogenic AA (PITTT) - phenylalanine, isoleucine, threonine, tryptophan, tyrosine
Ketogenic ONLY - leucine and lysine
The rest are glucogenic.

170

The following is an enzyme required for glycolysis

A. Pyruvate kinase
B. Pyruvate carboxylase
C. Glucose-6-phosphatase
D. Glycero kinase

A. Pyruvate kinase - along with hexokinase, and phosphofructokinase

Glucogenesis - pyruvate carboxylase, PEP carboxylkinase, frustose 1,6 biphosphatase, and glucose-6-phosphatase

171

The following is an enzyme required for glycolysis

A. Pyruvate kinase
B. Pyruvatecarboxylase
C. Glucose-6-phosphatase
D. Glycerokinase

A. Pyruvate kinase- final step of glycolysis, converts phosphoenolpyruvate to pyruvate


Enzymes of Glucogenesis - pyruvate carboxylase, PEP carboxylkinase, frustose 1,6 biphosphatase, and glucose-6-phosphatase

172

The normal glucose tolerance curve reaches peak in:

A. 15 mins
B. 1 hr
C. 2 hrs
D. 2 1⁄2hrs

B. 1 hr

173

Oxidative decarboxylation of pyruvate requires:

A. NADP+
B. Cytochromes
C. Pyridoxal phosphate
D. CoASH


D. CoASH

Oxidative decarboxylation = conversion of pyruvate to acetyl coA. This is catalyzed by the pyruvate dehydrogenase complex. This complex is composed of:
3 enzymes :
Pyruvate decarboxylase, dihydrolipoamide transacetylase, dihydrolipoamide dehydrogenase 5 coenzymes :
Thiamine pyrophosphate, lipoic acid, FAD, NAD+, CoASH

174

Glucose tolerance is increased in:

A. Diabetes mellitus
B. Adrenalectomy
C. Acromegaly
D. Thyrotoxicosis

B. Adrenalectomy

175

Glucose tolerance is decreased in:

A. Diabetes mellitus
B. Hypopituitarism
C. Addison’sdisease
D. Hypothyroidism

A. Diabetes mellitus

176

During glycolysis, fructose-1,6-bisphosphate is decomposed by the enzyme:

A. Enolase A
B. Fructokinase
C. Aldolase
D. Bisphosphofructophosphatase

C. Aldolase

177

The following enzyme is required for the hexose monophosphate shunt pathway:

A. Glucose-6-phosphatase
B. Phosphorylase
C. Aldolase
D. Glucose-6-phosphate dehydrogenase



72.
D. Phosphatase
This is in the glycogenolysis pathway.

D. Glucose-6-phosphate dehydrogenase

178

Dehydrogenase enzymes of the hexose monophosphate shunt are:

A. NAD+ specific
B. NADP+ specific
C. FAD specific
D. FMN specific

B. NADP+ specific

179

Under anaerobic conditions, the glycolysis of one mole of glucose yields how many moles of ATP?

A. One
B. Two
C. Eight
D. Thirty

B. Two

180

Glycogen is converted to glucose-1-phosphate by:

A. UDPGtransferase
B. Branchingenzyme
C. Phosphorylase
D. Phosphatase

C. Phosphorylase

181

Which of the following is NOT an enzyme involved in glycolysis?

A. Enolase
B. Aldolase
C. Hexokinase
D. Glucose oxidase

D. Glucose oxidase

182

Tricarboxylic acid cycle to be continuous requires the regeneration of:

A. Pyruvic acid
B. Oxaloacetic acid
C. Alpha-oxoglutaric acid
D. Malic acid

B. Oxaloacetic acid

183

Dehydrogenation of succinic acid to fumaric acid requires the following hydrogen carrier:

A. NAD+
B. NADP+
C. Flavoprotein
D. Glutathione

C. Flavoprotein - FAD

184

The tissues with the highest total glycogen content are the:

A. Muscle and kidneys
B. Kidneys and liver
C. Liver and muscle
D. Brain and liver

C. Liver and muscle

185

Rothera test is NOT given by:

A. Alpha-hydroxybutyrate
B. Bilesalts
C. Hypothyroidism
D. All give a (+) Rothera test

A. Alpha-hydroxybutyrate

Rothera test is a test for presence of ketone bodies in urine, Beta-hydroxbutyrate is a ketone body not alpha :)

186

Gluconeogenesis is increased in which of the following conditions?

A. Diabetes insipidus
B. Diabetes mellitus
C. Hypothyroidism
D. Liver disease

B. Diabetes mellitus

187

The oxidation of lactic acid to pyruvic acid requires the following vitamin derivative as the hydrogen carrier:

A. Lithium pyrophosphate
B. CoenzymeA
C. NAD+
D. FMN

C. NAD+

188

Physiological glycosuria is met with in which of the following conditions:

A. Renal glycosuria
B. Alimentary glycosuria
C. Diabetes mellitus
D. Alloxan diabetes

A. Renal glycosuria

189

Two examples of substrate level phosphorylation in Embden-Meyerhoff pathway of glucose metabolism are in the reactions of:

A. 1,3 bisphosphoglycerate and phosphoenolpyruvate
B. Glucose-6 phosphate and Fructo-6-phosphate
C. 3 phosphoglyceraldehyde and phosphoenolpyruvate
D. 1,3 bisphosphoglycerate and 2-phosphoglycerate

A. 1,3 bisphosphoglycerate and phosphoenolpyruvate

190

The number of molecules of ATP produced by the total oxidation of acetyl CoA in TCA cycle is:

A. 6
B. 8
C. 10
D. 12

C. 10

191

Substrate level of phosphorylation in TCA cycle is in the step catalyzed by:

A. Isocitrate dehydrogenase
B. Malate dehydrogenase
C. Aconitase
D. Succinate thiokinase



D. Succinate thiokinase

Succinate thiokinase cleaves the high-energy thioester bond of succinyl CoA. Succinyl CoA ➡ Succinate. This reaction is coupled to phosphorylation of GDP to GTP. The generation of GTP by Succinate thiokinase is an example of substrate level hphosphorylation. (Lippincott)

192

Fatty acids cannot be converted into carbohydrates in the body as the following reaction is not possible:

A. Conversion of glucose-6-phosphate into glucose
B. Fructose1,6-bisphosphate to fructose-6-phosphate
C. Transformation of acetyl CoA to pyruvate
D. Formation of acetyl CoA from fatty acids

C. Transformation of acetyl CoA to pyruvate

193

Tissues form lactic acid from glucose. This phenomenon is termed as:

A. Aerobic glycolysis
B. Oxidation
C. Oxidative phosphorylation
D. Anaerobic glycolysis

D. Anaerobic glycolysis

194

One molecule of glucose gives how many molecules of CO2 in Embden-Meyerhoff pathway-TCA cycle?

A. 6
B. 3
C. 1
D. 2

A. 6

The Embden-Meyerhoff pathway (glycolysis) - TCA cycle produces 6 CO2 molecules, 10 NADH molecules, and 2 FADH2 molecules per glucose molecule.

195

One molecule of glucose gives how many molecules of CO2 in one round of HMP shunt?

A. 6
B. 1
C. 2
D. 3

B. 1

196

The 4 rate limiting enzymes of gluconeogenesis are:

A. Glucokinase, pyruvate carboxylase, PEPCK, and glucose-6-phosphatase
B. Pyruvate carboxylase, PEPCK, fructose-1,6 bisphosphatase, and glucose-6-phosphatase
C. Pyruvate kinase, pyruvate carboxylase, PEPCK, and glucose-6-phosphatase
D. Phosphofructokinase, pyruvate carboxylase, PEPCK, and fructose-1,6 bisphosphatase

B. Pyruvate carboxylase, PEPCK, fructose-1,6 bisphosphatase, and glucose-6-phosphatase

other
A. glucokinase is wrong
C. pyruvate kinase is wrong
D. phosphofructukinase is wrong

197

For glycogenesis, glucose should be converted to:

A. Glucuronic acid
B. Pyruvic acid
C. UDP glucose
D. Sorbitol

C. UDP glucose

198

Fluoride inhibits which of the following enzymes and arrests glycolysis:

A. Glyceraldehyde-3-phosphate dehydrogenase
B. Aconitase
C. Enolase
D. Succinate dehydrogenase

C. Enolase

199

Amylo- 1,6-glucosidase is called:

A. Branching enzyme
B. Debranching enzyme
C. Glucatransferase
D. Phosphorylase

B. Debranching enzyme

200

Glucose enters the cells by:

A. Insulin independent transport - insulin does not significantly stimulate glucose transport
in the liver, brain (GLUT 1) & RBCs
B. Insulin dependent transport - insulin stimulated via GLUT 4 into muscles & adipose
C. Enzyme mediated transport
D. Both A and B are true

D. Both A and B are true

201

Glycogen while being acted upon by active phosphorylase is converted first to:

A. Glucose
B. Glucose 1-phosphate and glycogen with 1 carbon less
C. Glucose 6-phosphate and glycogen with 1 carbon less
D. 6-Phosphogluconic acid

B. Glucose 1-phosphate and glycogen with 1 carbon less - via glycogen phosphorylase

202

When O2 supply is inadequate, pyruvate is converted to:

A. Phosphopyruvate
B. AcetylCoA
C. Lactate
D. Alanine

C. Lactate

203

Reactivation of inactive liver phosphorylase is normally favored by:

A. Insulin
B. Epinephrine
C. ACTH
D. Glucagon

D. Glucagon

204

Before pyruvic enters the TCA cycle it must be converted to:

A. Acetyl CoA
B. Lactate
C. Alpha-ketoglutarate
D. Citrate

A. Acetyl CoA

205

The hydrolysis of glucose-6-phosphate is catalyzed by a specific phosphatase which is found only in:

A. Liver, intestines and kidneys
B. Brain, spleen and adrenals
C. Striated muscle
D. Palms

A. Liver, intestines and kidneys

206

The formation of citrate from oxaloacetate and acetyl CoA is:

A. Oxidation
B. Reduction
C. Condensation
D. Hydrolysis

C. Condensation

207

Which one of the following is a rate limiting enzyme of gluconeogenesis?

A. Hexokinase
B. Phosphofructokinase
C. Pyruvate carboxylase
D. Pyruvate kinase

C. Pyruvate carboxylase

208

L-glucose and D-glucose are pairs of structures that are mirror images of each other. These are examples of:

a. isomers
b.epimers
c. enantiomers d. anomers

c. enantiomers

209

The major dietary polysaccharide that is of animal origin.

a. glycogen
b. amylase
c. amylopectin
d. cellulose

a. glycogen

210

During digestion of carbohydrates , which organ secretes bicarbonate that neutralizes high acidity of food?

a. stomach
b. jejunum
c. duodenum
d. pancreas

d. pancreas

211

Which of the following statements about Fructose Metabolism is correct?

a. Entry of fructose into cells is dependent on insulin.
b. Hexokinase phosphorylates glucose in all cells of the body since it has a high affinity for fructose.
c. Fructokinase provides the primary mechanism for fructose phosphorylation.
d.Fructose 1-phosphate is converted to fructose-1, 6 bisphosphate , cleaning aldolase B into DHAP.

c. Fructokinase provides the primary mechanism for fructose phosphorylation.

212

Sorbitol accumulates in cells where sorbitol dehydrogenase is low or absent. This accumulation causes strong osmotic effects on these cells producing pathologic alterations including the following except one:

a. cataract formation
b. malignancy
c. peripheral neuropathy d. nephropathy

b. malignancy

213

Absence of this enzyme causes accumulation of galactose in cells:

a. Uridyl transferase
b. Lactose synthase
c. Aldolase B
d. Hexokinase

a. Uridyl transferase

214

Which process is slow in responding to a falling blood glucose but can provide sustained synthesis of glucose?

a. Aerobic glycolysis
b. Anaerobic glycolysis c. Gluconeogenesis
d. Glycogenolysis

c. Gluconeogenesis

215

Which Glycogen Storage Disease affects the skeletal muscles causing temporary weakness and cramping muscles after exercise?

a. Von Gierke's Disease b. Pompe's Disease
c. Mc Ardle's Disease d. Type I

c. Mc Ardle's Disease

216

Which enzyme is a tetramer activated by binding of glucagon or epinephrine to their specific cell-memebrane receptors?

a. protein kinase b. phosphorylase kinase
c. glycogen phosphorylase d. glycogen synthase

a. protein kinase

217

Glycosaminoglycans are large complexes of negatively charged heteroplohysaccharides that stabilize and support cellular and fibrous components of tissues while maintaining water and salt balance. The most abundant glycosaminoglycan in the body is:

a. Keratan sulfate
b. Hyaluronic acid
c. Chondroitin sulfate
d. Dermatan sulfate

c. Chondroitin sulfate

218

The principal sites of dietary carbohydrate digestion are:

a. mouth and intestinal lumen
b. duodenum and jejunum
c. mouth and stomach
d. stomach and intestinal lumen

a. mouth and intestinal lumen

219

This enzyme is synthesized by the mammary gland prior to and during pregnancy:

a. Lactalbumin
b. N-acetyllactosamine c. Lactose synthase
d. Protein A

b. N-acetyllactosamine

220

Glycogen serves as a fuel reserve for the synthesis of ATP during muscle contraction and during the early stages of fast. It is synthesized from molecules of glucose occurring in the:

a. cytosol
b. mitochondria
c. lysosome
d. both mitochondria and cytosol

a. cytosol

221

Which out of the following a carbohydrate with no nutritional value?

a.Dextrin
b. Starch
c. Cellulose
d. Glycogen

c. Cellulose

222

The major metabolic product produced under normal circumstances by erythrocytes and by muscles during intense exercise is recycled through liver in the Cori cycle. The metabolite is:

a. Alanin
b. Oxaloacetate
c. Glycerol
d. Lactate

d. Lactate

223

A 15 years old male presents with increased hunger, thirst, urination and weight loss. His fasting blood glucose is 500mg/dl and was diagnosed with diabetes mellitus type 1. What is the reason for the patient's inability to maintain a normal blood glucose?

a. decreased uptake of glucose by peripheral cells
b. abnormal response to glucagon
c. decreased glucagon to insulin ratio
d. decreased glucose output by the liver

a. decreased uptake of glucose by peripheral cells

224

A 30 years old female presented with central obesity, relatively thin extremities and purple stria on the abdomen. Further work-up revealed excess cortisol level and blood sugar level of 399mg/dl. Which of the following is the most likely cause of hyperglycemia?

a. excessive consumption of carbohydrates
b. pancreatic adenoma secreting ACTH and glucagon
c. cortisol induced inhibition of insulin
d. glucocorticoids cause induction of phosphoenolpyruvate carnoxy kinase gene

d. glucocorticoids cause induction of phosphoenolpyruvate carnoxy kinase gene

225

Which of the following substrates cannot contribute to net gluconeogenesis in mammalian liver?

a. Alanine
b. Glutamate
c. Palmitate
d. Pyruvate

c. Palmitate

226

A 16 years old high school girl who is extremely conscious about her figure and appearance went on a full day fasting to fit into a dress she wanted to wear for a party. Which of the following organs contributes to the glucose that is being synthesized through gluconeogenesis?

a. spleen
b. red blood cells
c. skeletal muscle
d. liver

d. liver