Question 1

The primary regulatory point of gluconeogenesis is ____.

Accepted Answer

A)  glucose-6-phosphatase 
B)  fructose-1,6-bisphosphatase 
C)  fructose-2,6-bisphosphatase 
D)  pyruvate carboxylase 
E)  PEP carboxykinase 
A)  glucose-6-phosphatase 
B)  fructose-1,6-bisphosphatase 
C)  fructose-2,6-bisphosphatase 
D)  pyruvate carboxylase 
E)  PEP carboxykinase

Question 2

The 6-phosphogluconate dehydrogenase reaction is an example of ____ and results in the production of ____.

Accepted Answer

A)  substrate-level phosphorylation; ATP 
B)  oxidative-decarboxylation; NADPH 
C)  TPP-assisted decarboxylation; NADH 
D)  phosphate addition; ADP 
E)  none of the above 
A)  substrate-level phosphorylation; ATP 
B)  oxidative-decarboxylation; NADPH 
C)  TPP-assisted decarboxylation; NADH 
D)  phosphate addition; ADP 
E)  none of the above

Question 3

The energy input for the synthesis of glycogen occurs during which of the following enzyme catalyzed steps?

Accepted Answer

A)  phosphoglucomutase 
B)  UDP-glucose pyrophosphorylase 
C)  glycogen synthase 
D)  amylo-(1,4→1,6)-transglycosylase 
E)  none of the above require energy input 
A)  phosphoglucomutase 
B)  UDP-glucose pyrophosphorylase 
C)  glycogen synthase 
D)  amylo-(1,4→1,6)-transglycosylase 
E)  none of the above require energy input

Question 4

The endoplasmic reticulum bound enzyme that hydrolyzes glucose-6-phosphate to glucose in liver is:

Accepted Answer

A)  glucokinase. 
B)  glucose oxidase. 
C)  hexokinase. 
D)  phosphoglucomutase. 
E)  glucose-6-phosphatase. 
A)  glucokinase. 
B)  glucose oxidase. 
C)  hexokinase. 
D)  phosphoglucomutase. 
E)  glucose-6-phosphatase.

Question 5

All are required for pyruvate carboxylase EXCEPT:

Accepted Answer

A)  biotin covalently linked to the enzyme. 
B)  thiamin pyrophosphate (TPP). 
C)  ATP. 
D)  acetyl-CoA as an allosteric activator. 
E)  tetrameric enzyme in the mitochondria. 
A)  biotin covalently linked to the enzyme. 
B)  thiamin pyrophosphate (TPP). 
C)  ATP. 
D)  acetyl-CoA as an allosteric activator. 
E)  tetrameric enzyme in the mitochondria.

Question 6

Discuss the regulation of gluconeogenesis by acetyl-CoA.​

Accepted Answer

Acetyl-CoA is a potent allosteric effect

Question 7

Transketolase belongs to what class of enzymes?

Accepted Answer

A)  oxidoreductases 
B)  isomerases 
C)  hydrolases 
D)  transferases 
E)  ligases 
A)  oxidoreductases 
B)  isomerases 
C)  hydrolases 
D)  transferases 
E)  ligases

Question 8

The transaldolase catalyzed activity is similar to what glycolytic enzyme?

Accepted Answer

A)  phosphoglucomutase 
B)  enolase 
C)  glyceraldehyde-3-phosphate dehydrogenase 
D)  PFK-1 
E)  aldolase 
A)  phosphoglucomutase 
B)  enolase 
C)  glyceraldehyde-3-phosphate dehydrogenase 
D)  PFK-1 
E)  aldolase

Question 9

Discuss the significance of the pentose phosphate pathway. What is the net reaction of the first four steps of the pathway?​

Accepted Answer

Cells require a constant supply of NADPH

Question 10

Insulin in the bloodstream is a response to increased blood glucose, and:

Accepted Answer

A)  stimulates gluconeogenesis. 
B)  inhibits glycolysis. 
C)  stimulates glycogen synthesis in muscle and liver. 
D)  stimulates glycogen breakdown in liver. 
E)  inhibits phosphoprotein phosphatase-1. 
A)  stimulates gluconeogenesis. 
B)  inhibits glycolysis. 
C)  stimulates glycogen synthesis in muscle and liver. 
D)  stimulates glycogen breakdown in liver. 
E)  inhibits phosphoprotein phosphatase-1.

Question 11

The pentose phosphate pathway is an important source of ____, and for ____, an essential precursor for ATP, NAD+, FAD, CoA, DNA and RNA.

Accepted Answer

A)  ATP; NADH 
B)  NADH; NADPH 
C)  NADPH; ribose-5-phosphate 
D)  ribose-5-phosphate; ATP 
E)  all are true 
A)  ATP; NADH 
B)  NADH; NADPH 
C)  NADPH; ribose-5-phosphate 
D)  ribose-5-phosphate; ATP 
E)  all are true

Question 12

Cellular levels of fructose-2,6-bisphosphate (F-2,6-BP) are controlled by the tandem enzyme ____ and ____.

Accepted Answer

A)  fructokinase; F-2,6-BPase 
B)  F-2,6-BPase; PFK-2 
C)  PFK-2; PFK-1 
D)  PFK-1; F-2,6-BPase 
E)  PFK-2; fructokinase 
A)  fructokinase; F-2,6-BPase 
B)  F-2,6-BPase; PFK-2 
C)  PFK-2; PFK-1 
D)  PFK-1; F-2,6-BPase 
E)  PFK-2; fructokinase

Question 13

A transaldolase is an enzyme that catalyzes:

Accepted Answer

A)  transfers of three-carbon units from a ketose to an aldose. 
B)  isomerization of ketoses into aldoses such as the conversion of ribulose-5-phosphate to ribose-5-phosphate. 
C)  epimerization of ketoses such as the conversion of xylulose-5-phosphate into ribulose-5-phosphate. 
D)  TPP-dependent transfer of 2-carbon units to the recipient aldose. 
E)  transfer of keto groups from C-2 to C-3 of a ketose. 
A)  transfers of three-carbon units from a ketose to an aldose. 
B)  isomerization of ketoses into aldoses such as the conversion of ribulose-5-phosphate to ribose-5-phosphate. 
C)  epimerization of ketoses such as the conversion of xylulose-5-phosphate into ribulose-5-phosphate. 
D)  TPP-dependent transfer of 2-carbon units to the recipient aldose. 
E)  transfer of keto groups from C-2 to C-3 of a ketose.

Question 14

Explain UDP-glucose synthesis.​

Accepted Answer

Sugar nucleotides-activated forms of sug

Question 15

Which of the following results when glucagon binds to its receptor?

Accepted Answer

A)  glycolysis is activated 
B)  protein synthesis is activated 
C)  the citric acid cycle is inhibited 
D)  glycogen synthesis is inhibited 
E)  gluconeogenesis is inhibited 
A)  glycolysis is activated 
B)  protein synthesis is activated 
C)  the citric acid cycle is inhibited 
D)  glycogen synthesis is inhibited 
E)  gluconeogenesis is inhibited

Question 16

The ratio of NADP+/NADPH in liver runs about 1/67 which means that:

Accepted Answer

A)  it is similar to the ratio of NAD+/NADH. 
B)  glucose-6-phosphate dehydrogenase will be turned on most of the time. 
C)  glucose-6-phosphate is rate limiting for pentose phosphate pathway. 
D)  glucose-6-phosphate preferentially goes to the pentose phosphate pathway. 
E)  glucose-6-phosphate dehydrogenase activity is dependent upon use of some of the NADPH before activity increases. 
A)  it is similar to the ratio of NAD+/NADH. 
B)  glucose-6-phosphate dehydrogenase will be turned on most of the time. 
C)  glucose-6-phosphate is rate limiting for pentose phosphate pathway. 
D)  glucose-6-phosphate preferentially goes to the pentose phosphate pathway. 
E)  glucose-6-phosphate dehydrogenase activity is dependent upon use of some of the NADPH before activity increases.

Question 17

Which of the following pairs of enzymes would NOT be active in the liver at the same time?

Accepted Answer

A)  aldolase and triose phosphate isomerase 
B)  fructose-1,6-bisphosphatase and phosphofructokinase-2 
C)  pyruvate kinase and phosphofructokinase-1 
D)  glycogen synthase and glucokinase 
E)  none of the above 
A)  aldolase and triose phosphate isomerase 
B)  fructose-1,6-bisphosphatase and phosphofructokinase-2 
C)  pyruvate kinase and phosphofructokinase-1 
D)  glycogen synthase and glucokinase 
E)  none of the above

Question 18

The reaction sequence for the pyruvate carboxylase catalyzed reaction is:
A.formation of N-carbonyl biotin
B.attack of HCO3− on ATP
C.liberation of Pi
D.formation of carbonylphosphate
E.C-3 carbanion of pyruvate attack on N-carbonyl biotin

Accepted Answer

A)  B, D, A, E, C 
B)  B, D, A, C, E 
C)  D, C, B, E, A 
D)  D, B, C, A, E 
E)  E, C, B, A, D 
A)  B, D, A, E, C 
B)  B, D, A, C, E 
C)  D, C, B, E, A 
D)  D, B, C, A, E 
E)  E, C, B, A, D

Question 19

In the Cori cycle, the liver ____ because it has a typically high ____.

Accepted Answer

A)  shares the load of exercising muscle; acetate level 
B)  converts lactate to lactose; galactose 
C)  shares the load of exercising muscle; NAD+/NADH ratio 
D)  burns fat; ATP 
E)  converts glucose to lactate; NAD+/NADH ratio 
A)  shares the load of exercising muscle; acetate level 
B)  converts lactate to lactose; galactose 
C)  shares the load of exercising muscle; NAD+/NADH ratio 
D)  burns fat; ATP 
E)  converts glucose to lactate; NAD+/NADH ratio

Question 20

Limit dextrins are degraded by the action of ____ which has two distinct enzymatic activities known as ____ and ____.

Accepted Answer

A)  α-amylase; β-amylase; α(1→6)glucosidase 
B)  debranching enzyme; oligo(α1,4→ α1,4)glucanotransferase; α(1→6)glucosidase. 
C)  debranching enzyme; oligo(α1,4→ α1,4)glucanotransferase; α(1→6)glucosidase 
D)  α-amylase; oligo(α1,4→ α1,6)glucanotransferase; α(1→6)glucosidase 
E)  α-amylase; β-amylase; oligo(α1,4→ α1,4)glucanotransferase 
A)  α-amylase; β-amylase; α(1→6)glucosidase 
B)  debranching enzyme; oligo(α1,4→ α1,4)glucanotransferase; α(1→6)glucosidase. 
C)  debranching enzyme; oligo(α1,4→ α1,4)glucanotransferase; α(1→6)glucosidase 
D)  α-amylase; oligo(α1,4→ α1,6)glucanotransferase; α(1→6)glucosidase 
E)  α-amylase; β-amylase; oligo(α1,4→ α1,4)glucanotransferase

Exam 22: Gluconeogenesis, Glycogen Metabolism, and the Pentose Phosphate Pathway

The primary regulatory point of gluconeogenesis is ____.

The 6-phosphogluconate dehydrogenase reaction is an example of ____ and results in the production of ____.

The energy input for the synthesis of glycogen occurs during which of the following enzyme catalyzed steps?

The endoplasmic reticulum bound enzyme that hydrolyzes glucose-6-phosphate to glucose in liver is:

All are required for pyruvate carboxylase EXCEPT:

Discuss the regulation of gluconeogenesis by acetyl-CoA.​

Transketolase belongs to what class of enzymes?

The transaldolase catalyzed activity is similar to what glycolytic enzyme?

Discuss the significance of the pentose phosphate pathway. What is the net reaction of the first four steps of the pathway?​

Insulin in the bloodstream is a response to increased blood glucose, and:

The pentose phosphate pathway is an important source of ____, and for ____, an essential precursor for ATP, NAD+, FAD, CoA, DNA and RNA.

Cellular levels of fructose-2,6-bisphosphate (F-2,6-BP) are controlled by the tandem enzyme ____ and ____.

A transaldolase is an enzyme that catalyzes:

Explain UDP-glucose synthesis.​

Which of the following results when glucagon binds to its receptor?

The ratio of NADP+/NADPH in liver runs about 1/67 which means that:

Which of the following pairs of enzymes would NOT be active in the liver at the same time?

The reaction sequence for the pyruvate carboxylase catalyzed reaction is: A.formation of N-carbonyl biotin B.attack of HCO3− on ATP C.liberation of Pi D.formation of carbonylphosphate E.C-3 carbanion of pyruvate attack on N-carbonyl biotin

In the Cori cycle, the liver ____ because it has a typically high ____.

Limit dextrins are degraded by the action of ____ which has two distinct enzymatic activities known as ____ and ____.

The Facts of Life: Chemistry Is the Logic of Biological Phenomena

Water: the Medium of Life

Thermodynamics of Biological Systems

Amino Acids and the Peptide Bond

Proteins: Their Primary Structure and Biological Functions

Proteins: Secondary, Tertiary, and Quaternary Structure

Carbohydrates and the Glycoconjugates of Cell Surfaces

Lipids

Membranes and Membrane Transport

Nucleotides and Nucleic Acids

Structure of Nucleic Acids

Recombinant Dna, Cloning, Chimeric Genes, and Synthetic Biology

Enzymeskinetics and Specificity

Mechanisms of Enzyme Action

Enzyme Regulation

Molecular Motors

Metabolism: an Overview

Glycolysis

The Tricarboxylic Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Fatty Acid Catabolism

Lipid Biosynthesis

Nitrogen Acquisition and Amino Acid Metabolism

Synthesis and Degradation of Nucleotides

Metabolic Integration and Organ Specialization

Dna Metabolism: Replication, Recombination, and Repair

Transcription and the Regulation of Gene Expression

Protein Synthesis

Completing the Protein Life Cycle: Folding, Processing, and Degradation

The Reception and Transmission of Extracellular Information

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The 6-phosphogluconate dehydrogenase reaction is an example of and results in the production of .

Discuss the regulation of gluconeogenesis by acetyl-CoA.

Discuss the significance of the pentose phosphate pathway. What is the net reaction of the first four steps of the pathway?

The pentose phosphate pathway is an important source of , and for , an essential precursor for ATP, NAD⁺, FAD, CoA, DNA and RNA.

Cellular levels of fructose-2,6-bisphosphate (F-2,6-BP) are controlled by the tandem enzyme and .

Explain UDP-glucose synthesis.

The ratio of NADP⁺/NADPH in liver runs about 1/67 which means that:

The reaction sequence for the pyruvate carboxylase catalyzed reaction is: A.formation of N-carbonyl biotin B.attack of HCO₃− on ATP C.liberation of P_i D.formation of carbonylphosphate E.C-3 carbanion of pyruvate attack on N-carbonyl biotin

In the Cori cycle, the liver because it has a typically high .

Limit dextrins are degraded by the action of which has two distinct enzymatic activities known as and .