BIO CHEM 7 Flashcards by ROLLIE ESTEVES

Which out of the following statements is true about regulation of metabolic pathway?

Most of the metabolic pathways are regulated

Most of the metabolic pathways are not regulated

Regulation of metabolic pathways always involves changing the amount of enzymes

Metabolic regulation always depends on control by hormones

Most of the metabolic pathways are regulated

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The rate of breakdown of metabolites is termed as

Metabolic state
Metabolism
Steady state
Homeostasis

Steady state

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Diminished delivery of oxygen to tissues is termed as

Hypoxia
Ischemia
Homeostasis
Metabolism

Hypoxia

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Diminished flow of blood to tissues is termed as

Hypoxia
Ischemia
Homeostasis
Metabolism

Ischemia

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Which of the following statements is true about the control of muscle glycogen phosphorylase?

It is activated by phosphorylation by an active phosphorylase kinase

It is allosterically activated by ATP

It is allosterically activated by cAMP

Normally it exists in active form

It is activated by phosphorylation by an active phosphorylase kinase

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Which of the following is not a factor determining the activity of an enzyme?

Association with regulatory protein
Sequestration
Allosteric regulation
Nucleotides

Nucleotides

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Which of the following statements is true?

High insulin/glucagon ratio activates lipolysis in muscle

High insulin/glucagon ratio inhibits lipolysis in liver

High insulin/glucagon ratio activates lipolysis in adipocytes

Low insulin/glucagon ratio activates lipolysis in adipocytes

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Which of the following type of metabolite is used for generating glucose under severe starvation conditions?

Amino acids
Fats
Glycogen
Starch

Amino acids

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Which of the following statements is true about brain metabolism in starvation?

The brain can use glucogenic amino acids for energy

The brain can only use glucose as fuel

Up to a quarter of energy requirement of the brain can come from fatty acids

Up to a half of energy requirement of the brain can come from ketone bodies

The brain can use glucogenic amino acids for energy

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ne of the following statements about the control of enzyme activity by phosphorylation is correct

Phosphorylation of an enzyme results in conformational change

Phosphorylation of an enzyme occurs only at specific tyrosine residues

Phosphorylation of an enzyme is carried out by phosphoprotein phosphatases

Enzyme control by phosphorylation is irreversible

Phosphorylation of an enzyme results in conformational change

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Gluconeogenesis responds to which of the following?

Hormonal control
pH control
Temperature control
Blood control

Hormonal control

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When blood sugar levels fall, glycolysis is halted in liver to allow

Homeostasis
Anaerobic respiration
Aerobic respiration
Gluconeogenesis

Gluconeogenesis

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How many steps are catalyzed by same enzymes in both glycolysis and gluconeogenesis?

6
7
8
9

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How many steps are catalyzed by different enzymes in glycolysis and gluconeogenesis?

2
3
4
5

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Three reactions of glycolysis are so exergonic, which are not catalyzed by

Hexokinase
PFK-1
Pyruvate kinase
Pyruvate dehydrogenase

Pyruvate dehydrogenase

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What are the effects of increased concentration of citrate?

Increases the inhibitory effect of ATP
Decreases the inhibitory effect of ATP
Increases the activity of ATP
Increases the activity of AMP

Increases the inhibitory effect of ATP

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The second control point in gluconeogenesis is the reaction catalyzed by

Pyruvate kinase
Pyruvate dehydrogenase
PFK-1

FBPase-1

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Which of the following statements is true about PFK-1?

It is stimulated by AMP and ADP
It is stimulated by citrate and ATP
It is inhibited by AMP and ADP
It is stimulated by citrate and ADP

It is stimulated by AMP and ADP

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Which of the following statements is true regarding acetyl co-A?

It stimulates pyruvate dehydrogenase
It stimulates pyruvate carboxylase
It inhibits pyruvate carboxylase
It stimulates hexokinase

It stimulates pyruvate carboxylase

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Which of the following is a potent regulator of glycolysis and gluconeogenesis?

Fructose 2, 6-bisphosphate
Fructose 1, 6-bisphosphate
Fructose 6-phosphate
Glucose 1, 6-bisphosphate

Fructose 2, 6-bisphosphate

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Glucagon and epinephrine stimulate glycogen breakdown to glucose 6-phosphate

Directly by binding to glycogen phosphorylase

Indirectly by first stimulating adenylate cyclase to make cAMP

Only in the liver

Only in muscle cells

Indirectly by first stimulating adenylate cyclase to make cAMP

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The compounds responsible for coordinated regulation of glucose and glycogen metabolism are

NADH
NAD+
Acetyl co-A
Fructose 2, 6-bisphosphate

Fructose 2, 6-bisphosphate

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Glycogen synthase a is activated by

Phosphorylation catalyzed by GSK3
Dephosphorylation catalyzed by GSK3
Phosphorylation catalyzed by pyruvate kinase
Phosphorylation catalyzed by pyruvate carboxylase

Phosphorylation catalyzed by GSK3

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Glucagon is released from

Muscle
Pancreas
Kidneys
Epithelial tissues

Pancreas

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Glucose 6-phosphatase is present only in Liver Muscle Epithelial tissues Kidneys

Liver

Which of the following enzymes is involved in the positive regulation of glycolysis/gluconeogenesis? Hexokinase II Hexokinase IV PFK-2/FBPase-2 Pyruvate kinase

PFK-2/FBPase-2

Which of the following enzymes is involved in fatty acid synthesis? Hexokinase II Hexokinase IV PFK-2/FBPase-2 Pyruvate dehydrogenase

Pyruvate dehydrogenase

Which of the following is involved in triacylglycerol synthesis? Hexokinase II Acyl co-A glycerol transferases PFK-2/FBPase-2 Pyruvate dehydrogenase

Acyl co-A glycerol transferases

Which of the following is involved in pentose phosphate pathway? Glucose 6-phosphate dehydrogenase Acyl co-A glycerol transferases PFK-2/FBPase-2 Pyruvate dehydrogenase

Glucose 6-phosphate dehydrogenase

Which of the following enzyme’s gene expression is slowed by insulin? Hexokinase II Hexokinase IV PEP carboxykinase Pyruvate kinase

PEP carboxykinase

Flux control coefficient measures the Steady state change pH change Temperature change Hormonal change

Steady state change

What is the relation between elasticity coefficient, flux coefficient and response coefficient? ``` R = C.ε R = C⁄ε R = ε⁄C ε = C.R ```

R = C.ε

Which of the following is a measure of the effect of an enzyme’s concentration on flux through a multi-enzyme pathway? Response coefficient Elasticity coefficient Flux control coefficient Metabolic control

Flux control coefficient

Which of the following is a measure of how responsive the enzyme is to changes in the concentration of a metabolite? Response coefficient Elasticity coefficient Flux control coefficient Metabolic control

Elasticity coefficient

An expression for the experimentally determined change in flux through a pathway in response to a regulatory hormone or second messenger Response coefficient Elasticity coefficient Flux control coefficient Metabolic control

Response coefficient

Which of the following statements about the control of glycogen synthesis from blood glucose in myocytes is incorrect? Insulin affects three of five steps in this pathway The effects on transport and hexokinase activity increase the flux towards glycogen The change in glycogen synthase activity increases the flux towards glycogen Hexokinase enzyme is involved

The change in glycogen synthase activity increases the flux towards glycogen

Some regulated enzymes control the flux through a pathway, this activity is Regulation Control Metabolism Anabolism

Control

Some regulated enzymes rebalance the level of metabolites in response to the change in flux, this activity is Regulation Control Metabolism Anabolism

Regulation

Metabolic control analysis does not suggests that When the blood glucose level rises, insulin acts in muscle to increase glucose transport into cells by bringing GLUT4 to the plasma membrane When the blood glucose level rises, insulin acts in muscle to induce the synthesis of PFK-1 When the blood glucose level rises, insulin acts in muscle to activate glycogen synthase by covalent alteration When the blood glucose level rises, insulin acts in muscle to induce the synthesis of hexokinase

When the blood glucose level rises, insulin acts in muscle to induce the synthesis of PFK-1

Which of the following is the most influential in setting the flux through glycolysis? Hexokinase PFK-1 PFK-2 Both hexokinase and PFK-1

Hexokinase

Glutamate is metabolically converted to α-ketoglutarate and NH4+ by a process Oxidative deamination Transamination Reductive deamination Deamination

Oxidative deamination

Free ammonia combined with glutamate to yield glutamine by the action of Glutaminase Glutamine synthase Glutamate dehydrogenase Amino transferase

Glutamine synthase

Pyridoxal phosphate and its aminate form, pyridoxamine phosphate are tightly bound coenzymes of Amino transferases Glutaminase Glutamine synthase Glutamate dehydrogenase

Amino transferases

The necessary coenzyme for transamination reactions is Pyridoxal phosphate Thiamine pyrophosphate NAD Coenzyme A

Pyridoxal phosphate

The first step in the catabolism of most L-amino acids once they have reached the liver is promoted by Amino transferases Glutaminase Glutamine synthase Glutamate dehydrogenase

Amino transferases

The combined action of aminotransferase and glutamate dehydrogenase is referred as Oxidative deamination Transamination Reductive deamination Transdeamination

Transdeamination

Glutamine is converted to glutamate and NH4+ by Amino transferases Glutaminase Glutamine synthase Glutamate dehydrogenase

Glutaminase

Which of the following operates at an important intersection of carbon and nitrogen metabolism? Amino transferases Glutaminase Glutamine synthase Glutamate dehydrogenase

Glutamate dehydrogenase

Trypsinogen is converted to its active state by Enteropeptidase Glutaminase Glutamine synthase Glutamate dehydrogenase

Enteropeptidase

Which of the following hydrolyzes successive amino-terminal residues from short peptides? Aminopeptidase Enteropeptidase Glutamine synthase Glutamate dehydrogenase

Aminopeptidase

Urea production occurs almost exclusively in Kidneys Liver Blood Urine

Liver

The first amino group entering into urea cycle is Carbomyl phosphate Ornithine Cituilline Argininosuccinate

Carbomyl phosphate

The first enzyme in the pathway carbamoyl phosphate synthase I, is allosterically activated by N-acetylglutamate Acetyl coA Glutamate Carbamoyl phosphate

N-acetylglutamate

A second amino group is transferred to cituilline from Aspartate Glutamate Alanine Guanine

Aspartate

Nitrogen atoms of urea produced in the urea cycle are derived from Ammonia and aspartic acid Nitrate Nitrite Ammonia

Ammonia and aspartic acid

Products of urea cycle are One molecule of urea, one molecule of ammonia, one molecule of ATP and one molecule of fumaric acid One molecule of urea, one molecule of AMP, two molecule of ADP and one molecule of fumaric acid One molecule of aspartic acid, one molecule of ammonia, one molecule of ATP and one molecule of fumaric acid Two molecules of urea, two molecules of ammonia, one molecule of ATP and one molecule of fumaric acid

One molecule of urea, one molecule of AMP, two molecule of ADP and one molecule of fumaric acid

The carbon atom source while producing urea in the urea cycle is CO2 Glucose Aspartic acid Arginine

CO2

Which of the following is not an essential amino acid? Glycine Leucine Methionine Histidine

Methionine

Urea cycle converts Keto acids into amino acids Amino acids into keto acids Ammonia into a less toxic form Ammonia into a more toxic form

Keto acids into amino acids

Inputs to one cycle of urea cycle are One molecule of CO2, one molecule of ammonia, three molecule of ATP and one molecule of aspartic acid One molecule of urea, one molecule of AMP, two molecule of ADP and one molecule of fumaric acid One molecule of aspartic acid, one molecule of ammonia, one molecule of ATP and one molecule of fumaric acid Two molecules of urea, two molecules of ammonia, one molecule of ATP and one molecule of fumaric acid

One molecule of CO2, one molecule of ammonia, three molecule of ATP and one molecule of aspartic ac

Which of the following amino acids are exclusively ketogenic? Leucine Asparagine Threonine Proline

Leucine

Which of the following are exclusively glucogenic? Arginine Leucine Lysine Threonine

Arginine

Which of the following yield acetyl co-A via aceto-acetyl co-A? Leucine Isoleucine Threonine Alanine

Leucine

Which of the following yield acetyl coA directly? Phenylalanine Isoleucine Lysine Alanine

Isoleucine

Which of the following produce pyruvate? Leucine Isoleucine Lysine Alanine

Alanine

Which of the following produce α-ketoglutarate? Leucine Threonine Methionine Proline

Proline

Which of the following produce succinyl co-A? Leucine Isoleucine Arginine Alanine

Isoleucine

Fumarate is produced from four carbon atoms of Tyrosine Isoleucine Threonine Alanine

Tyrosine

Which of the following produce oxaloacetate? Aspartate Isoleucine Threonine Alanine

Aspartate

The branched chain amino acid is not Leucine Isoleucine Valine Alanine

Alanine

Protein that contains nucleic acid derivative of riboflavin is called Nucleic acid Amino acid Flavoprotein None

Flavoprotein

NADP-linked dehydrogenase catalyzes Glucose 6-phosphate+NADP+ ↔ 6-phosphogluconate + NADPH + H+ Lactate + NAD+ ↔ pyruvate + NADH + H+ Pyruvate + CoA + NAD+ ↔ acetyl-CoA + CO2 + NADH + H+ L-Malate + NAD+ ↔ oxaloacetate + NADH + H+

Glucose 6-phosphate+NADP+ ↔ 6-phosphogluconate + NADPH + H+

A lipid-soluble benzoquinone with a long isoprenoid side chain Ubiquinone Cytochrome b Cytochrome c Cytochrome a

Ubiquinone

The only membrane bound enzyme in the citric acid cycle is Succinate dehydrogenase NADH dehydrogenase ATP synthase Acyl co-A dehydrogenase

Succinate dehydrogenase

The first step in the β oxidation of fatty acyl co-A is catalyzed by Succinate dehydrogenase NADH dehydrogenase ATP synthase Acyl co-A dehydrogenase

Acyl co-A dehydrogenase

Complex 1 is also called a. NADH dehydrogenase b. Succinate dehydrogenase c. Cytochrome bc1 complex d. Cytochrome oxidase

NADH dehydrogenase

Complex 2 is also called NADH dehydrogenase Succinate dehydrogenase Cytochrome bc1 complex Cytochrome oxidase

Succinate dehydrogenase

Complex 3 is also called NADH dehydrogenase Succinate dehydrogenase Cytochrome bc1 complex Cytochrome oxidase

Cytochrome bc1 complex

Complex 4 is also called NADH dehydrogenase Succinate dehydrogenase Cytochrome bc1 complex Cytochrome oxidase

Cytochrome oxidase

In mitochondria, hydride ions are removed from substrates by NAD-linked dehydrogenases NADP-linked dehydrogenases ATP synthase Succinate dehydrogenases

NAD-linked dehydrogenases

Which of the following is the prosthetic group of NADH dehydrogenase? NADH FAD NADPH FMN

FMN

Effect of valinomycin on oxidative phosphorylation does not involve pH gradient across the inner mitochondrial membrane decreases Rate of flow of electrons increases Rate of oxygen consumption increases Net yield of ATP decreases

pH gradient across the inner mitochondrial membrane decreases

If mitochondria were blocked at the site of NADH oxidation and were treated with succinate as substrate, what would the P : O ratio is? Same as that normally produced by succinate One more than normally produced by succinate One less than normally produced by succinate Zero

Same as that normally produced by succinate

If 2, 4-dinitrophenol is added to tightly coupled mitochondria that are actively oxidizing succinate Electron flow will continue but ATP synthesis will not occur Electron flow will continue but ATP synthesis will be increased Electron flow will cease but ATP synthesis will continue Both electron flow and ATP synthesis will be ceased

Electron flow will continue but ATP synthesis will not occur

If the oxidative phosphorylation was uncoupled in the mitochondria then there is a/an Decreased concentration of ADP in the mitochondria Decreased oxidative rate Increased inorganic phosphate in the mitochondria Decreased production of heat

Increased inorganic phosphate in the mitochondria

If rotenone is added to the mitochondrial electron transport chain Succinate oxidation remains normal P: O ratio of NADH is reduced from 3:1 to 2:1 Oxidative phosphorylation is uncoupled at site I Rate of NADH oxidation is diminished to two-thirds of its initial value

Succinate oxidation remains normal

Which of the following takes place in substrate level phosphorylation? Oxidation of one molecule of substrate is linked to synthesis of more than one ATP molecule High energy intermediate compounds cannot be isolated Only mitochondrial reactions participate in ATP formation Substrate reacts to form a product containing a high energy bond

Substrate reacts to form a product containing a high energy bond

Chemiosmotic hypothesis does not involve Only proton transport is strictly regulated, other positively charged ions can diffuse freely across the mitochondrial membrane ATPase activity is reversible Proton flow in to the mitochondria depends on the presence of ADP and Pi Electron transport by the respiratory chain pumps protons out of the mitochondria

Only proton transport is strictly regulated, other positively charged ions can diffuse freely across the mitochondrial membrane

Out of the following the one having highest redox potential is Ubiquinone O2 FMN NAD

Which of the following accepts only one electron? Cytochrome b Coenzyme Q FMN FAD

Cytochrome b

The proposal of chemiosmotic hypothesis was by Peter D. Mitchell Charles Darwin Mendele Alfred Russell

Peter D. Mitchell

ATP synthesis by chemiosmosis is by ATP dehydrogenase Gyrase ATP synthase Dehydrogenase

ATP synthase

The measure of potential energy stored as combination of proton and voltage gradients across membrane is termed as Proton motive force Electron motive force Molecule motive force Ion motive force

Proton motive force

The transport of acyl co-A for oxidation using a shuttle involves formation of the intermediate Acyl coenzyme A 3 acetyl co-A Acyl cartinine None

Acyl cartinine

Three identical β subunits of the F1 complex during ATP synthesis have Different affinities for ATP and ADP Similar affinities for ADP and ATP Different affinities for ADP but not ATP Different affinities for ATP but not ADP

Different affinities for ATP and ADP

The acyl co-A formed in the cytosol is transported to Mitochondrial matrix Microsomes ER Remains in cytosol

Mitochondrial matrix

Every cycle of β-oxidation produces 1 FAD, 1 NAD+ and 2 CO2 molecules 1 FADH2, 1 NADH and 1 acetyl co-A 1 FADH2, 1 NAD+ and 1 acetyl co-A 1 FAD, 1 NADH and 2 CO2 molecules

1 FADH2, 1 NADH and 1 acetyl co-A

Membrane potential and proton gradient Cancel one another when uncouplers are present Reinforce one another when respiratory inhibitors are present Are sufficient, separately to make ATP from ADP + Pi Are required to make ATP

Are required to make ATP

Long-chain fatty acids are oxidized step-wise in one carbon units starting from Carboxyl end Aliphatic end a and b None

Carboxyl end

Maximum energy per gram on oxidation is yielded from Starch Fat Glycogen Protein

Fat

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BIO CHEM 7 Flashcards

(101 cards)