Question 1

All blood glucose in humans is derived from carbohydrate sources included in the diet.

Accepted Answer

A) True 
 B)False

Question 2

Which of the following is not a precursor for gluconeogenesis?

Accepted Answer

A) Propionate. 
B) Glycerol. 
C) Lactate. 
D) Acetate. 
E) Ethanol. 
A) Propionate. 
B) Glycerol. 
C) Lactate. 
D) Acetate. 
E) Ethanol.

Question 3

Glycogenin is a protein scaffold for glycogen as well as an enzyme catalyzing extension of the glycogen primer.

Accepted Answer

A) True 
 B)False

Question 4

The activity of phosphoenolpyruvate carboxykinase (PEPCK)is most affected by

Accepted Answer

A) glucagon concentration. 
B) insulin concentration. 
C) the level of PEPCK gene transcription. 
D) the elevation of cAMP concentration on fasting. 
A) glucagon concentration. 
B) insulin concentration. 
C) the level of PEPCK gene transcription. 
D) the elevation of cAMP concentration on fasting.

Question 5

Which statement is true about the reaction catalyzed by glycogen synthase?

Accepted Answer

A) It polymerizes free glucose to glycogen in the liver. 
B) It requires UTP-glucose for chain lengthening. 
C) It can both lengthen glycogen chains as well as form new branches. 
D) It requires a primer of four to eight linked glucose residues. 
A) It polymerizes free glucose to glycogen in the liver. 
B) It requires UTP-glucose for chain lengthening. 
C) It can both lengthen glycogen chains as well as form new branches. 
D) It requires a primer of four to eight linked glucose residues.

Question 6

The brain normally uses both glucose and fatty acids as energy sources.

Accepted Answer

A) True 
 B)False

Question 7

In ruminants,microorganisms produce propionate.The three-carbon acid must be converted to ________ before entering the gluconeogenesis pathway.

Accepted Answer

A) acetyl CoA 
B) lactate 
C) citric acid 
D) succinyl CoA 
A) acetyl CoA 
B) lactate 
C) citric acid 
D) succinyl CoA

Question 8

Protein kinase A,which stimulates glycogen degradation,is activated directly by

Accepted Answer

A) glucagon. 
B) insulin. 
C) epinephrine. 
D) cyclic AMP. 
E) adrenergic receptors. 
A) glucagon. 
B) insulin. 
C) epinephrine. 
D) cyclic AMP. 
E) adrenergic receptors.

Question 9

The enzyme transketolase transfers 2-carbon units from ketose phosphates to aldose phosphates.

Accepted Answer

A) True 
 B)False

Question 10

Which substance is not needed for the conversion of glucose to fructose?

Accepted Answer

A) NADPH. 
B) Aldose reductase. 
C) QH². 
D) NAD+. 
A) NADPH. 
B) Aldose reductase. 
C) QH². 
D) NAD+.

Question 11

All species can make glucose from two-carbon or three-carbon precursors.

Accepted Answer

A) True 
 B)False

Question 12

The reaction that converts amino acids into keto acids (such as pyruvate)is called

Accepted Answer

A) the Cori cycle. 
B) catabolism. 
C) transamination. 
D) dehydrogenation. 
A) the Cori cycle. 
B) catabolism. 
C) transamination. 
D) dehydrogenation.

Question 13

The only known regulatory mechanism for pyruvate carboxylase is

Accepted Answer

A) activation by acetyl CoA. 
B) activation by phosphorylation. 
C) activation by cAMP. 
D) activation by NADH. 
A) activation by acetyl CoA. 
B) activation by phosphorylation. 
C) activation by cAMP. 
D) activation by NADH.

Question 14

A substrate cycle in a metabolic pathway ________.

Accepted Answer

A) is a good point for regulation of the pathway 
B) includes only diffusion-controlled reactions 
C) allows for substrates to be passed to alternative pathways 
D) is a point that starts a cascade effect 
A) is a good point for regulation of the pathway 
B) includes only diffusion-controlled reactions 
C) allows for substrates to be passed to alternative pathways 
D) is a point that starts a cascade effect

Question 15

The activity of glycogen phosphorylase can be controlled by

Accepted Answer

A) phosphorylation. 
B) ATP. 
C) glucose 6-phosphate. 
D) protein subunit separation. 
E) All of the above. 
A) phosphorylation. 
B) ATP. 
C) glucose 6-phosphate. 
D) protein subunit separation. 
E) All of the above.

Question 16

The sequence of enzymes active in liver to degrade glycogen in response to glucagon is: ________.(~P indicates phosphorylation)

Accepted Answer

A) Protein kinase A,phosphorylase kinase~P,glycogen phosphorylase a~P 
B) protein kinase A,glycogen phosphorylase a~P,phosphorylase kinase~P 
C) phosphorylase kinase,glycogen phosphorylase b,protein kinase A 
D) phosphorylase kinase,glycogen phosphorylase b,protein kinase A,glucagon 
A) Protein kinase A,phosphorylase kinase~P,glycogen phosphorylase a~P 
B) protein kinase A,glycogen phosphorylase a~P,phosphorylase kinase~P 
C) phosphorylase kinase,glycogen phosphorylase b,protein kinase A 
D) phosphorylase kinase,glycogen phosphorylase b,protein kinase A,glucagon

Question 17

What is the driving force for the reaction catalyzed by UDP-glucose pyrophosphorylase that converts glucose 1-phosphate to UDP-glucose?

Accepted Answer

A) Its large negative free energy change. 
B) The formation of an energy-rich product. 
C) The subsequent hydrolysis of pyrophosphate. 
D) The change in concentration of UTP. 
A) Its large negative free energy change. 
B) The formation of an energy-rich product. 
C) The subsequent hydrolysis of pyrophosphate. 
D) The change in concentration of UTP.

Question 18

What is the prosthetic group of transketolase?

Accepted Answer

A) Thiamine pyrophosphate. 
B) Biotin. 
C) Pyridoxal phosphate. 
D) NAD+. 
A) Thiamine pyrophosphate. 
B) Biotin. 
C) Pyridoxal phosphate. 
D) NAD+.

Question 19

Glycogen phosphorylase acts on the non-reducing ends of glycogen.

Accepted Answer

A) True 
 B)False

Question 20

Glycogen storage disease results in glycogen accumulation in the liver and kidneys.It can be controlled by changing the diet.

Accepted Answer

A) True 
 B)False

Exam 12: Gluconeogenesis, the Pentose Phosphate Pathway, and Glycogen Metabolism

All blood glucose in humans is derived from carbohydrate sources included in the diet.

Which of the following is not a precursor for gluconeogenesis?

Glycogenin is a protein scaffold for glycogen as well as an enzyme catalyzing extension of the glycogen primer.

The activity of phosphoenolpyruvate carboxykinase (PEPCK)is most affected by

Which statement is true about the reaction catalyzed by glycogen synthase?

The brain normally uses both glucose and fatty acids as energy sources.

In ruminants,microorganisms produce propionate.The three-carbon acid must be converted to ________ before entering the gluconeogenesis pathway.

Protein kinase A,which stimulates glycogen degradation,is activated directly by

The enzyme transketolase transfers 2-carbon units from ketose phosphates to aldose phosphates.

Which substance is not needed for the conversion of glucose to fructose?

All species can make glucose from two-carbon or three-carbon precursors.

The reaction that converts amino acids into keto acids (such as pyruvate)is called

The only known regulatory mechanism for pyruvate carboxylase is

A substrate cycle in a metabolic pathway ________.

The activity of glycogen phosphorylase can be controlled by

The sequence of enzymes active in liver to degrade glycogen in response to glucagon is: ________.(~P indicates phosphorylation)

What is the driving force for the reaction catalyzed by UDP-glucose pyrophosphorylase that converts glucose 1-phosphate to UDP-glucose?

What is the prosthetic group of transketolase?

Glycogen phosphorylase acts on the non-reducing ends of glycogen.

Glycogen storage disease results in glycogen accumulation in the liver and kidneys.It can be controlled by changing the diet.

Introduction to Biochemistry

Water

Amino Acids and the Primary Structures of Proteins

Proteins: Three-Dimensional Structure and Function

Properties of Enzymes

Mechanisms of Enzymes

Coenzymes and Vitamins

Carbohydrates

Lipids and Membranes

Introduction to Metabolism

Glycolysis

The Citric Acid Cycle

Electron Transport and Atp Synthesis

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Nucleic Acids

DNA Replication, repair, and Recombination

Transcription and RNA Processing

Protein Synthesis

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