Question 1

Which of the following best describes the two main phases of glycolysis?

Accepted Answer

An energy-investment phase followed by an energy-generation phase

Question 2

During glycolysis, what is the net gain of ATP molecules per molecule of glucose?

Accepted Answer

$$2$$

Question 3

Which enzyme catalyzes the phosphorylation of glucose to glucose-6-phosphate in the first step of glycolysis?

Accepted Answer

Hexokinase

Question 4

Phosphofructokinase (PFK) is a major control point in glycolysis. Which of the following best describes its regulation?

Accepted Answer

It is an allosteric enzyme activated by AMP and inhibited by ATP

Question 5

Which reaction in glycolysis is an example of substrate-level phosphorylation?

Accepted Answer

The conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate by phosphoglycerate kinase

Question 6

Which of the following statements about the fate of pyruvate under anaerobic conditions is correct?

Accepted Answer

Pyruvate is reduced to lactate to regenerate $$NAD^+$$

Question 7

Which enzyme in gluconeogenesis bypasses the irreversible reaction catalyzed by pyruvate kinase in glycolysis?

Accepted Answer

Pyruvate carboxylase and phosphoenolpyruvate carboxykinase

Question 8

The Cori cycle is important for which physiological process?

Accepted Answer

Recycling lactate produced in muscles back to glucose in the liver

Question 9

Which of the following best explains why glycolysis and gluconeogenesis are reciprocally regulated?

Accepted Answer

To prevent futile cycles and ensure efficient use of energy

Question 10

Which enzyme is responsible for cleaving $$\alpha(1 \rightarrow 4)$$ glycosidic bonds in glycogen during glycogenolysis?

Accepted Answer

Glycogen phosphorylase

Question 11

What is the main function of the pentose phosphate pathway (PPP)?

Accepted Answer

To generate NADPH and ribose-5-phosphate

Question 12

Which of the following statements about the digestion of amylopectin or glycogen is correct?

Accepted Answer

$$\alpha-$$amylase cleaves $$\alpha(1 \rightarrow 4)$$ linkages but cannot cleave $$\alpha(1 \rightarrow 6)$$ linkages at branch points

Question 13

Which of the following is an irreversible reaction in glycolysis that must be bypassed in gluconeogenesis?

Accepted Answer

Phosphofructokinase reaction

Question 14

A patient with a deficiency in glucose-6-phosphatase would have difficulty with which metabolic process?

Accepted Answer

Gluconeogenesis

Question 15

Which of the following best describes the role of UDP-glucose in glycogen synthesis?

Accepted Answer

It is an activated form of glucose used by glycogen synthase

Question 16

Which of the following steps in glycolysis is driven forward by the spontaneous tautomerization of the product?

Accepted Answer

Conversion of phosphoenolpyruvate to pyruvate by pyruvate kinase

Question 17

Which of the following is a product of the reaction catalyzed by glyceraldehyde 3-phosphate dehydrogenase (GAPDH) in glycolysis?

Accepted Answer

1,3-bisphosphoglycerate

Question 18

Which of the following best explains why the reaction catalyzed by aldolase proceeds in vivo despite a positive $$\Delta G^\circ'$$?

Accepted Answer

The actual $$\Delta G$$ under intracellular conditions is negative

Question 19

Which of the following is a key reason why the regulation of glycolysis and gluconeogenesis must be coordinated?

Accepted Answer

To prevent simultaneous operation of both pathways, which would waste energy

Glycolysis, Gluconeogenesis, and Glycogen Metabolism: Key Pathways in Carbohydrate Biochemistry

Study Guide - Practice Questions