Question 1

Which of the following best describes the effect of increasing substrate concentration on the rate of an enzyme-catalyzed reaction, assuming enzyme concentration is constant?

Accepted Answer

The reaction rate will increase with substrate concentration until it reaches a maximum velocity ($$V_{max}$$), after which it plateaus.

Question 2

A competitive inhibitor affects enzyme activity by:

Accepted Answer

Binding to the active site, preventing substrate binding.

Question 3

Which equation represents the Michaelis-Menten relationship for enzyme kinetics?

Accepted Answer

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

Question 4

During a warm-up, muscle temperature increases from 30°C to 40°C. What is the physiological effect on muscle contraction and relaxation rates?

Accepted Answer

Contraction rate increases and relaxation rate becomes faster.

Question 5

Which of the following is a direct result of enzyme phosphorylation by a protein kinase?

Accepted Answer

A phosphate group is added to the enzyme, potentially altering its activity.

Question 6

Allosteric regulation of enzymes involves:

Accepted Answer

Binding of a molecule to a regulatory site, changing enzyme shape and activity.

Question 7

Which of the following best explains why a drug with high affinity for its target enzyme can reduce side effects?

Accepted Answer

High affinity drugs bind more specifically, so lower doses are needed.

Question 8

Which process is described by the following equation: $$	ext{enzyme} + P_i \xrightarrow{	ext{Protein kinase}} 	ext{enzyme} - P$$?

Accepted Answer

Phosphorylation

Question 9

A decrease in pH due to lactic acid accumulation during intense exercise will most likely:

Accepted Answer

Slow down the rate of enzyme-catalyzed reactions.

Question 10

Which statement about covalent regulation of enzymes is correct?

Accepted Answer

It requires formation or breaking of covalent bonds between the enzyme and a chemical group.

Question 11

In glycolysis, which type of enzyme regulation is most likely to control the pathway’s rate?

Accepted Answer

Allosteric regulation at key steps.

Question 12

Which of the following is true regarding the relationship between enzyme affinity and substrate concentration?

Accepted Answer

Enzymes with high affinity reach $$V_{max} at $$lower substrate concentrations.

Question 13

Which of the following is an example of feedback inhibition in metabolic pathways?

Accepted Answer

A product of the pathway binds to an enzyme early in the pathway, reducing its activity.

Question 14

Which of the following best explains the effect of temperature on enzyme-catalyzed reactions?

Accepted Answer

Increasing temperature increases enzyme activity up to an optimal point, after which activity decreases due to denaturation.

Question 15

Which of the following is a multi-step regulatory mechanism for enzyme activity?

Accepted Answer

Allosteric regulation followed by covalent modification (e.g., phosphorylation).

Question 16

Which of the following is true about the effect of training on muscle enzyme content?

Accepted Answer

Training increases the number of enzymes, enhancing reaction rates.

Question 17

Which of the following best describes substrate-level phosphorylation?

Accepted Answer

Direct transfer of a phosphate group to ADP to form ATP.

Question 18

Which of the following is a consequence of allosteric inhibition?

Accepted Answer

The enzyme’s shape is altered, reducing its affinity for the substrate.

Question 19

Which of the following is true regarding the effect of enzyme concentration on reaction rate?

Accepted Answer

Increasing enzyme concentration increases reaction rate, provided substrate is not limiting.

Enzymes: Structure, Function, and Regulation in Human Physiology

Study Guide - Practice Questions

Study Guide - Flashcards