$$2 \text{ pyruvate}, 2 \text{ ATP}, 2 \text{ NADH}, 2 \text{ H}^+$$

$$\text{Glucose} + 2 \text{ADP} + 2 \text{P}_i + 2 \text{H}^+ \rightarrow 2 \text{lactate} + 2 \text{ATP} + 2 \text{H}_2O$$

$$4 \text{ ATP} + 2 \text{ GTP} + 2 \text{ NADH}$$ are consumed per glucose synthesized

Question 1

Which of the following best describes the net products of glycolysis from one molecule of glucose under anaerobic conditions?

Accepted Answer

$$2 	ext{ pyruvate}, 2 	ext{ ATP}, 2 	ext{ NADH}, 2 	ext{ H}^+$$

Question 2

During the energy-investment phase of glycolysis, which of the following occurs?

Accepted Answer

Two ATP molecules are consumed to convert glucose into two triose phosphates.

Question 3

Which enzyme catalyzes the first irreversible step of glycolysis, and what is its substrate?

Accepted Answer

Hexokinase; substrate is glucose

Question 4

Which of the following equations correctly represents homolactic fermentation?

Accepted Answer

$$	ext{Glucose} + 2 	ext{ADP} + 2 	ext{P}_i + 2 	ext{H}^+ ightarrow 2 	ext{lactate} + 2 	ext{ATP} + 2 	ext{H}_2O$$

Question 5

Which of the following statements about gluconeogenesis is correct?

Accepted Answer

Gluconeogenesis requires bypassing three irreversible steps of glycolysis using distinct enzymes.

Question 6

Which enzyme is responsible for converting fructose-1,6-bisphosphate to fructose-6-phosphate in gluconeogenesis?

Accepted Answer

Fructose-1,6-bisphosphatase

Question 7

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

Accepted Answer

Gluconeogenesis

Question 8

Which molecule acts as a key allosteric activator of phosphofructokinase (PFK) in glycolysis?

Accepted Answer

AMP

Question 9

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

Accepted Answer

To generate NADPH and ribose-5-phosphate for biosynthetic reactions

Question 10

Which of the following best explains the Pasteur effect?

Accepted Answer

The rate of glucose utilization decreases when cells are exposed to oxygen due to inhibition of glycolysis

Question 11

Which enzyme catalyzes the conversion of glucose-1-phosphate to glucose-6-phosphate during glycogen breakdown?

Accepted Answer

Phosphoglucomutase

Question 12

Which of the following is a direct product of glycogen phosphorylase action on glycogen?

Accepted Answer

$$\alpha-D-$$glucose-1-phosphate

Question 13

Which of the following is true regarding the energy cost of gluconeogenesis from pyruvate?

Accepted Answer

$$4 	ext{ ATP} + 2 	ext{ GTP} + 2 	ext{ NADH}$$ are consumed per glucose synthesized

Question 14

Which of the following statements about the Cori cycle is correct?

Accepted Answer

It involves the conversion of lactate produced in muscle to glucose in the liver

Question 15

Which of the following is a key regulatory mechanism that prevents futile cycling between glycolysis and gluconeogenesis?

Accepted Answer

Reciprocal allosteric regulation of key enzymes

Question 16

Which of the following is a function of fructose-2,6-bisphosphate in liver cells?

Accepted Answer

It activates glycolysis and inhibits gluconeogenesis

Question 17

A patient presents with abnormally long, unbranched glycogen chains in the liver. Which enzyme is most likely deficient?

Accepted Answer

Branching enzyme (amylo-(1,4 to 1,6) glycosylase)

Question 18

Which of the following best describes the role of NADPH produced by the pentose phosphate pathway?

Accepted Answer

It provides reducing power for biosynthetic reactions such as fatty acid synthesis

Question 19

Which of the following is a common fate of pyruvate under anaerobic conditions in human muscle cells?

Accepted Answer

Reduction to lactate

Question 20

Which of the following best explains why glycolysis is regulated at multiple steps?

Accepted Answer

To ensure metabolic intermediates are available for other biosynthetic pathways and to prevent wasteful energy expenditure

Carbohydrate Metabolism: Glycolysis, Gluconeogenesis, Glycogen Metabolism, and Pentose Phosphate Pathway

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