Question 1

Which of the following enzymes catalyzes the committed step of glycolysis?

Accepted Answer

Phosphofructokinase-1 (PFK-1)

Question 2

During gluconeogenesis, which enzyme bypasses the irreversible step catalyzed by pyruvate kinase in glycolysis?

Accepted Answer

Pyruvate carboxylase and phosphoenolpyruvate carboxykinase (PEPCK)

Question 3

Which of the following best describes the net reaction of glycolysis?

Accepted Answer

$$\mathrm{Glucose} + 2\ \mathrm{NAD}^+ + 2\ \mathrm{ADP} + 2\ \mathrm{P_i} \rightarrow 2\ \mathrm{Pyruvate} + 2\ \mathrm{NADH} + 2\ \mathrm{ATP} + 2\ \mathrm{H_2O} + 2\ \mathrm{H}^+$$

Question 4

Which of the following molecules is NOT an intermediate in glycolysis?

Accepted Answer

Citrate

Question 5

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

Accepted Answer

Gluconeogenesis

Question 6

Which of the following statements about the regulation of glycolysis and gluconeogenesis is CORRECT?

Accepted Answer

Fructose-2,6-bisphosphate activates glycolysis and inhibits gluconeogenesis.

Question 7

Which enzyme catalyzes the conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate, generating ATP in glycolysis?

Accepted Answer

Phosphoglycerate kinase

Question 8

In the Cori cycle, which tissue converts lactate back to glucose?

Accepted Answer

Liver

Question 9

Which of the following is a key regulatory enzyme unique to gluconeogenesis?

Accepted Answer

Fructose-1,6-bisphosphatase

Question 10

A mutation causes phosphofructokinase-1 (PFK-1) to lose its sensitivity to ATP inhibition. What is the most likely metabolic consequence?

Accepted Answer

Glycolysis will proceed unchecked, even when ATP is abundant.

Question 11

Which of the following best explains why gluconeogenesis is not simply the reverse of glycolysis?

Accepted Answer

Some steps in glycolysis are highly exergonic and must be bypassed by different enzymes in gluconeogenesis.

Question 12

Which of the following is a substrate for gluconeogenesis but NOT for glycolysis?

Accepted Answer

Lactate

Question 13

If a cell is deprived of NAD+, which step of glycolysis will be directly inhibited?

Accepted Answer

Glyceraldehyde-3-phosphate dehydrogenase

Question 14

Which of the following best describes the role of pyruvate carboxylase in gluconeogenesis?

Accepted Answer

It converts pyruvate to oxaloacetate, using ATP and bicarbonate.

Question 15

Which of the following is a net product of gluconeogenesis from two molecules of pyruvate?

Accepted Answer

$$\mathrm{Glucose} + 4\ \mathrm{ADP} + 2\ \mathrm{GDP} + 6\ \mathrm{P_i} + 2\ \mathrm{NAD}^+ + 6\ \mathrm{H}^+$$

Question 16

Which of the following conditions would most likely increase the rate of gluconeogenesis in the liver?

Accepted Answer

High glucagon levels

Question 17

Which glycolytic enzyme is responsible for substrate-level phosphorylation?

Accepted Answer

Pyruvate kinase

Question 18

A patient presents with lactic acidosis due to a deficiency in an enzyme of gluconeogenesis. Which enzyme is most likely deficient?

Accepted Answer

Pyruvate carboxylase

Question 19

Which of the following best explains why red blood cells rely exclusively on glycolysis for ATP production?

Accepted Answer

They lack mitochondria.

Question 20

Which of the following is a key difference between glycolysis and gluconeogenesis?

Accepted Answer

Glycolysis generates ATP, while gluconeogenesis consumes ATP.

Glycolysis and Gluconeogenesis (Chapter 14) - Overview

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