Question 1

Which of the following best describes a hydrolysis reaction in biological systems?

Accepted Answer

A reaction where water is used to break a bond, resulting in two smaller molecules.

Question 2

In the reaction $\mathrm{C_6H_{12}O_6} + 6\ \mathrm{O_2} \rightarrow 6\ \mathrm{CO_2} + 6\ \mathrm{H_2O}$, which molecule is being oxidized?

Accepted Answer

$\mathrm{C_6H_{12}O_6}$

Question 3

Which of the following statements about enzymes is TRUE?

Accepted Answer

Enzymes lower the activation energy required for a reaction to proceed.

Question 4

A student mixes glucose and fructose in water and observes the formation of sucrose and water. Which type of reaction has occurred?

Accepted Answer

Condensation

Question 5

Which of the following best represents the law of conservation of energy as it applies to chemical reactions in the body?

Accepted Answer

Energy is transformed from one form to another but is neither created nor destroyed.

Question 6

During phosphorylation, which of the following occurs?

Accepted Answer

A phosphate group ($P_i$) is added to a molecule.

Question 7

Which of the following is an example of an endergonic (anabolic) reaction?

Accepted Answer

The synthesis of proteins from amino acids.

Question 8

If a reaction is at equilibrium, which of the following is TRUE?

Accepted Answer

The forward and reverse reaction rates are equal.

Question 9

Which of the following best describes the role of oxygen in cellular respiration?

Accepted Answer

Oxygen acts as a powerful oxidant, accepting electrons at the end of the electron transport chain.

Question 10

A reaction in the body is described as: $\mathrm{A} + \mathrm{B} \rightleftharpoons \mathrm{C} + \mathrm{D}$. If the concentration of A and B increases, what will happen according to the law of mass action?

Accepted Answer

The reaction will shift to produce more C and D.

Question 11

Which of the following is a correct example of a redox reaction?

Accepted Answer

$\mathrm{HA-BH} \rightarrow \mathrm{A=B} + 2\ \mathrm{H}^+$

Question 12

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

Accepted Answer

The equilibrium constant ($K$) of the reaction

Question 13

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

Accepted Answer

The enzyme's activity will decrease because the inhibitor competes with the substrate for the active site.

Question 14

Which of the following best describes the difference between catabolic and anabolic reactions?

Accepted Answer

Catabolic reactions release energy by breaking down molecules, while anabolic reactions require energy to build molecules.

Question 15

Which of the following is an example of dephosphorylation?

Accepted Answer

$\mathrm{ATP} + \mathrm{H_2O} \rightarrow \mathrm{ADP} + \mathrm{P_i}$

Question 16

Which of the following statements about coenzymes is TRUE?

Accepted Answer

Coenzymes are organic molecules that transfer chemical groups between molecules.

Question 17

A scientist observes that increasing the temperature of an enzyme-catalyzed reaction increases the rate up to a point, but then the rate sharply decreases. What is the most likely explanation?

Accepted Answer

The enzyme is denatured at high temperatures, losing its functional shape.

Question 18

Which of the following best explains why reactions in the body are often bidirectional?

Accepted Answer

Because the concentrations of reactants and products can change, shifting the direction of the reaction.

Question 19

Which of the following is a correct statement about the equilibrium constant ($K$) for a reaction?

Accepted Answer

$K$ is determined by the concentrations of reactants and products at equilibrium.

Enzymes and Biochemical Reactions: Foundations for Anatomy & Physiology

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