Question 1

Which of the following best describes the structural difference between an aldose and a ketose monosaccharide?

Accepted Answer

An aldose contains an aldehyde group at the first carbon, while a ketose contains a ketone group at the second carbon.

Question 2

Which of the following statements about D- and L- monosaccharides is correct?

Accepted Answer

D- and L- forms are determined by the configuration of the asymmetric carbon furthest from the carbonyl group.

Question 3

Which of the following best explains why cellulose cannot be digested by humans?

Accepted Answer

Cellulose is composed of β(1→4) glycosidic bonds, and humans lack the enzyme to hydrolyze these bonds.

Question 4

During the conversion of glucose to pyruvate in glycolysis, which enzyme catalyzes the rate-limiting step?

Accepted Answer

Phosphofructokinase-1 (PFK-1)

Question 5

Which of the following is a correct description of substrate-level phosphorylation?

Accepted Answer

It is the direct transfer of a phosphate group from a high-energy substrate to ADP, forming ATP.

Question 6

Which of the following best describes the function of the pentose phosphate pathway (PPP)?

Accepted Answer

It generates NADPH and ribose-5-phosphate for biosynthetic reactions.

Question 7

A patient with a deficiency in glucose-6-phosphate dehydrogenase would have difficulty with which of the following processes?

Accepted Answer

Production of NADPH in the oxidative phase of the pentose phosphate pathway

Question 8

Which of the following is the correct systematic name for sucrose?

Accepted Answer

$$\alpha-D-$$glucopyranosyl-(1\rightarrow2)-$$\beta-D-$$fructofuranoside

Question 9

Which of the following best explains the physiological significance of the extensive branching in glycogen?

Accepted Answer

It increases the number of terminal glucose residues, facilitating rapid mobilization of glucose.

Question 10

Which of the following statements about the regulation of glycogen metabolism is correct?

Accepted Answer

Glucagon activates glycogen phosphorylase and inhibits glycogen synthase.

Question 11

Which of the following is a key difference between hexokinase and glucokinase?

Accepted Answer

Glucokinase has a higher $$K_m$$ for glucose and is not inhibited by glucose-6-phosphate.

Question 12

Which of the following best describes the process of mutarotation?

Accepted Answer

The interconversion between the $$\alpha$$ and $$\beta$$ anomers of a cyclic monosaccharide in aqueous solution.

Question 13

A patient presents with muscle fatigue during intense exercise. Which enzyme's regulation is most likely responsible for the rapid increase in glycolytic flux in muscle cells?

Accepted Answer

Muscle isoform of phosphofructokinase-1 (PFK-1), which is highly sensitive to AMP activation

Question 14

Which of the following reactions is catalyzed by an isomerase during glycolysis?

Accepted Answer

Glucose-6-phosphate $$\rightarrow$$ Fructose-6-phosphate

Question 15

Which of the following best explains why NAD+ regeneration is essential during anaerobic glycolysis?

Accepted Answer

NAD+ is required for the oxidation of glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate.

Question 16

Which of the following is a product of the oxidative phase of the pentose phosphate pathway?

Accepted Answer

Ribulose-5-phosphate and NADPH

Question 17

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

Accepted Answer

It serves as the activated glucose donor for elongation of the glycogen chain.

Question 18

Which of the following best explains the effect of a high [NADPH]:[NADP+] ratio on the pentose phosphate pathway?

Accepted Answer

It inhibits glucose-6-phosphate dehydrogenase, decreasing NADPH production.

Question 19

Which of the following is a correct statement about the Cori cycle?

Accepted Answer

It describes the conversion of lactate produced in muscles to glucose in the liver.

Comprehensive Study Notes: Carbohydrates and Their Metabolic Pathways

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