Question 1

Which statement best describes the difference between the lock-and-key model and the induced fit model of enzyme-substrate binding?

Accepted Answer

The lock-and-key model suggests the enzyme's active site is rigid and fits the substrate exactly, while the induced fit model suggests the active site is flexible and molds itself around the substrate.

Question 2

Which of the following best describes the role of cofactors in enzyme activity?

Accepted Answer

Cofactors are non-protein molecules that are required for some enzymes to function properly.

Question 3

Which equation correctly represents the Michaelis-Menten model for enzyme kinetics?

Accepted Answer

$$v = \frac{V_{max} [S]}{K_m + [S]}$$

Question 4

A patient is given a drug that acts as a competitive inhibitor for a key metabolic enzyme. What effect will this have on the enzyme's activity?

Accepted Answer

The apparent $$K_m$$ will increase, but $$V_{max}$$ will remain unchanged.

Question 5

Which of the following statements about ATP is correct?

Accepted Answer

ATP is an energy carrier that releases energy when its terminal phosphate bond is hydrolyzed.

Question 6

During glycolysis, what is the fate of pyruvate under anaerobic conditions in muscle cells?

Accepted Answer

Pyruvate is converted to lactate to regenerate NAD$$^+.$$

Question 7

Which of the following reactions occurs during gluconeogenesis but not during glycolysis?

Accepted Answer

Conversion of pyruvate to phosphoenolpyruvate

Question 8

Which molecule acts as the final electron acceptor in the electron transport chain?

Accepted Answer

O$$_2$$

Question 9

How many ATP molecules are produced from the complete aerobic oxidation of one molecule of glucose?

Accepted Answer

30-32

Question 10

Which of the following best explains why fatty acids yield more ATP per carbon than carbohydrates?

Accepted Answer

Fatty acids are more reduced than carbohydrates, allowing for more oxidation and ATP production.

Question 11

Which step is required to transport a fatty acid from the cytosol into the mitochondria for beta-oxidation?

Accepted Answer

Attachment of fatty acid to carnitine

Question 12

If a saturated fatty acid with 16 carbons undergoes complete beta-oxidation, how many acetyl-CoA molecules are produced?

Accepted Answer

8

Question 13

Which of the following is a glucogenic amino acid?

Accepted Answer

Alanine

Question 14

Which enzyme catalyzes the conversion of pyruvate to acetyl-CoA?

Accepted Answer

Pyruvate dehydrogenase

Question 15

In the citric acid cycle, which molecule is formed by the condensation of acetyl-CoA and oxaloacetate?

Accepted Answer

Citrate

Question 16

Which of the following statements about NADH and FADH$$_2 is $$correct?

Accepted Answer

NADH donates electrons to Complex I, while FADH$$_2$$ donates electrons to Complex II.

Question 17

Which process is responsible for the conversion of lactate back to glucose in the liver?

Accepted Answer

Gluconeogenesis

Question 18

Which of the following is a key regulatory enzyme in glycolysis that is activated by high levels of AMP?

Accepted Answer

Phosphofructokinase-1 (PFK-1)

Question 19

Which reaction in the citric acid cycle directly produces GTP (or ATP)?

Accepted Answer

Conversion of succinyl-CoA to succinate

Question 20

During oxidative phosphorylation, what is the main driving force for ATP synthesis?

Accepted Answer

The proton gradient across the inner mitochondrial membrane

Metabolic Pathways, Enzyme Function, and Energy Production: GOB Chemistry Study Guide

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