Question 1

Which of the following best describes an exergonic reaction in terms of energy change?

Accepted Answer

Energy in reactants is greater than energy in products; energy is released.

Question 2

A patient presents with muscle weakness and elevated levels of creatine kinase in plasma. Which clinical condition is most likely indicated by these findings?

Accepted Answer

Muscular dystrophy

Question 3

Which equation correctly represents the hydrolysis of a disaccharide?

Accepted Answer

$$A-B + H_2O \rightarrow A-OH + B-H$$

Question 4

Which enzyme catalyzes the phosphorylation of glucose during glycolysis?

Accepted Answer

Hexokinase

Question 5

What is the primary function of cofactors in enzymatic reactions?

Accepted Answer

They help the enzyme maintain its normal conformation and activity.

Question 6

Which of the following statements about activation energy is correct?

Accepted Answer

Activation energy is the minimum energy required to start a chemical reaction.

Question 7

A metabolic pathway is regulated by feedback inhibition. Which of the following best describes this process?

Accepted Answer

The end product of the pathway inhibits an earlier enzyme, slowing or stopping production.

Question 8

Which of the following is an example of a covalent regulation of enzyme activity?

Accepted Answer

Phosphorylation of an enzyme by a protein kinase

Question 9

Which equation represents the synthesis of ATP by oxidative phosphorylation?

Accepted Answer

$$ADP + P_i \rightarrow ATP + H_2O$$

Question 10

A patient with obstructive jaundice is likely to have elevated levels of which plasma enzyme?

Accepted Answer

Alkaline phosphatase

Question 11

Which of the following best explains the induced-fit model of enzyme action?

Accepted Answer

The enzyme changes shape to fit the substrate upon binding, forming a transition state.

Question 12

Which of the following factors does NOT directly affect the rate of an enzyme-catalyzed reaction?

Accepted Answer

Concentration of product only after equilibrium is reached

Question 13

Which of the following is true regarding chemical equilibrium in metabolic reactions?

Accepted Answer

It is reached when the rates of the forward and reverse reactions are equal.

Question 14

Which enzyme is responsible for the breakdown of hydrogen peroxide into water and oxygen?

Accepted Answer

Catalase

Question 15

A genetic mutation leads to a deficiency in glucose-6-phosphatase. Which metabolic consequence is most likely?

Accepted Answer

Impaired removal of phosphate from glucose-6-phosphate

Question 16

Which of the following best describes an anabolic reaction?

Accepted Answer

Synthesis of larger molecules from smaller ones, requiring energy input

Question 17

Which vitamin-derived coenzyme is involved in the transfer of acetyl groups?

Accepted Answer

Coenzyme A (pantothenate, B5)

Question 18

Which of the following is a correct representation of a phosphorylation reaction?

Accepted Answer

$$A + P \rightarrow AP$$

Question 19

Which enzyme catalyzes the conversion of lactic acid to pyruvic acid?

Accepted Answer

Lactate dehydrogenase

Question 20

A metabolic pathway is limited by the slowest step, known as the rate-limiting reaction. Which enzyme is most likely to be regulated in this pathway?

Accepted Answer

The enzyme catalyzing the rate-limiting step

Metabolic Reactions and Enzymes: Foundations of Biochemistry in Anatomy & Physiology

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