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, how many net ATP molecules are produced 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

Which glycolytic enzyme is considered the major regulatory control point and is allosterically regulated?

Accepted Answer

Phosphofructokinase (PFK)

Question 5

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

Accepted Answer

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 converted 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

A patient is fasting and their glycogen stores are depleted. Which pathway is primarily responsible for maintaining their blood glucose levels?

Accepted Answer

Gluconeogenesis

Question 9

Which organ is the most active in gluconeogenesis, especially during prolonged fasting or intense exercise?

Accepted Answer

Liver

Question 10

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

Accepted Answer

To prevent futile cycles and conserve energy

Question 11

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

Accepted Answer

Glycogen phosphorylase

Question 12

What is the role of UDP-glucose in glycogen synthesis?

Accepted Answer

It acts as an activated glucose donor for glycogen synthase

Question 13

Which enzyme is required to remove the $$\alpha(1 \rightarrow 6)$$ branch point in glycogen during its degradation?

Accepted Answer

$$\alpha(1 \rightarrow 6)-$$glucosidase (debranching enzyme)

Question 14

Which of the following is a product of the pentose phosphate pathway that is essential for nucleotide synthesis?

Accepted Answer

Ribose-5-phosphate

Question 15

A mutation in phosphofructokinase (PFK) would most directly affect which step in glycolysis?

Accepted Answer

Conversion of fructose-6-phosphate to fructose-1,6-bisphosphate

Question 16

Which of the following best describes the Cori cycle?

Accepted Answer

It recycles lactate produced in muscle back to glucose in the liver

Question 17

Which of the following is a key regulatory enzyme in glycogen breakdown that is activated by phosphorylation?

Accepted Answer

Glycogen phosphorylase

Question 18

Which of the following is a direct product of the reaction catalyzed by enolase in glycolysis?

Accepted Answer

Phosphoenolpyruvate (PEP)

Question 19

Which of the following best explains why the conversion of phosphoenolpyruvate (PEP) to pyruvate is highly exergonic?

Accepted Answer

The spontaneous tautomerization of enolpyruvate to the more stable keto form (pyruvate)

Question 20

Which of the following is NOT a fate of glucose-6-phosphate in the cell?

Accepted Answer

Direct conversion to acetyl-CoA

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