Question 1

What is the primary regulatory point of gluconeogenesis?

Accepted Answer

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

Question 2

Which major tissues carry out gluconeogenesis?

Accepted Answer

A) brain and muscles 
B) muscles and kidneys 
C) liver and kidneys 
D) red blood cells and brain

Question 3

Which of the following is NOT a physiological effect of insulin?

Accepted Answer

A) inhibition of glycogen phosphorylase 
B) inducement of synthesis of glucokinase,PFK-1,and pyruvate kinase 
C) stimulation of active transport of glucose and amino acids into muscle and adipose tissues 
D) stimulation of fructose-1,6-bisphosphatase

Question 4

What is synthesized in gluconeogenesis?

Accepted Answer

A) glucose from non-carbohydrate precursors 
B) glycogen from glucose 
C) pyruvate from glucose 
D) fatty acids from glucose

Question 5

Glucose monitoring devices use the reaction,glucose + O₂ + 2 H₂O → gluconate + 2 H₂O₂.Which enzyme catalyzes this reaction?

Accepted Answer

A) gluconate synthase 
B) glucose oxidase. 
C) peroxidase 
D) glucose oxidase

Question 6

Which enzyme catalyzes bicarbonate "activation" by attachment to the g-phosphate of ATP to form carbonyl phosphate?

Accepted Answer

A) glucokinase 
B) glucose-6-phosphatase 
C) PEP carboxykinase 
D) pyruvate carboxylase

Question 7

Which process describes the 6-phosphogluconate dehydrogenase reaction?

Accepted Answer

A) substrate-level phosphorylation 
B) oxidative decarboxylation 
C) TPP-assisted decarboxylation 
D) phosphate addition

Question 8

The ratio of NADP⁺/NADPH in liver runs about 1/67.What does this mean?

Accepted Answer

A) Glucose-6-phosphate dehydrogenase activity is dependent upon use of some of the NADPH before activity increases. 
B) Glucose-6-phosphate dehydrogenase will be turned on most of the time. 
C) Glucose-6-phosphate is rate limiting for the pentose phosphate pathway. 
D) Glucose-6-phosphate goes preferentially to the pentose phosphate pathway.

Question 9

Epinephrine elicits many physiological changes such as the initiation of the adenylyl cyclase cascade.Which of these actions is NOT seen as a result of this initiation?

Accepted Answer

A) stimulation of glycogen synthase 
B) activation of glycogenolysis in liver 
C) stimulation of glycolysis by 2000-fold 
D) activation of glycogenolysis in muscles

Question 10

Which of the following is NOT an enzyme in the enzyme cascade for activation of glycogen phosphorylase?

Accepted Answer

A) adenylyl cyclase 
B) protein kinase A 
C) hormone-sensitive lipase 
D) phosphorylase kinase

Question 11

What does the enzyme transketolase catalyze?

Accepted Answer

A) transfers of 3-carbon units from a ketose to an aldose 
B) transfer of ketoses into aldoses 
C) TPP-dependent transfer of 2-carbon units to the recipient aldose 
D) keto-group transfer from C-2 to C-3

Question 12

Which of these reactions represents the gluconeogenic reversal of PFK-1 in glycolysis?

Accepted Answer

A) fructose-6-P + ADP→ fructose + ATP 
B) fructose-6-P + H₂O →fructose + Pi 
C) fructose-1,6-bisphosphate + ADP →fructose-6-P + ATP 
D) fructose-1,6-bisphosphate + H₂O →fructose-6-P + Pi

Question 13

Which enzyme-catalyzed reaction is analogous to the phosphopentose isomerase reaction and mechanism?

Accepted Answer

A) UDP-glucose epimerase 
B) phosphoglycerate isomerase 
C) phosphopentose epimerase 
D) phosphoglucoisomerase

Question 14

The polyol pathway is a suspected pathway for diabetes-induced cataract formation.Which enzyme does it involve?

Accepted Answer

A) aldose reductase 
B) glucose-6-phosphate dehydrogenase 
C) phosphopentose isomerase 
D) transaldolase

Question 15

Glucose-6-phosphatase is located in the endoplasmic reticulum.What does the enzyme produce in vesicles that diffuse to the plasma membrane,releasing their contents into the blood stream?

Accepted Answer

A) lactate 
B) glucose-6-phosphate 
C) sucrose 
D) glucose

Question 16

Insulin in the bloodstream is a response to increased blood glucose.What does insulin do as a result of this?

Accepted Answer

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

Question 17

Which of the following is NOT correct for a-amylase?

Accepted Answer

A) Its activity is reduced in highly branched regions of polysaccharides and stops 4 residues from any branch point. 
B) It is an important component of saliva and pancreatic juice. 
C) It catalyzes hydrolysis of ? (1?6)linkages in amylopectin. 
D) It catalyzes hydrolysis of ? (1?4)linkages in glycogen.

Question 18

Which of these reactions is catalyzed by a transketolase in the pentose phosphate pathway?

Accepted Answer

A) erythrose-4-P + fructose-6-P ↔sedoheptulose-7-P + glyceraldehyde-3-P 
B) sedoheptulose-7-P + glyceraldehyde-3-P ↔ erythrose-4-P + fructose-6-P 
C) fructose-6-P + glyceraldehyde-3-P ↔ xylulose-5-P + erythrose-4-P 
D) glucose-6-P +2 NADP+ + H₂0 ↔ ribose-5-P +2 NADPH +2 H⁺

Question 19

In the Cori cycle,the liver shares the load of exercising muscle.What is this a result of?

Accepted Answer

A) high acetate levels 
B) high galactose levels 
C) a high NAD⁺/NADH ratio 
D) a high FAD/FADH ratio

Question 20

Which of the following enzymes is NOT unique to gluconeogenesis?

Accepted Answer

A) phosphoglucoisomerase 
B) glucose-6-phosphatase 
C) fructose-1,6-bisphosphatase 
D) PEP carboxykinase

Exam 21: Gluconeogenesis, glycogen Metabolism, and the Pentose Phosphate Pathway