Question 1

Which of the following best describes a metabolic pathway?

Accepted Answer

A series of chemical reactions, each catalyzed by a specific enzyme, that begins with a specific molecule and ends with a product.

Question 2

According to the first law of thermodynamics, which of the following statements is correct?

Accepted Answer

Energy can be transferred and transformed, but it cannot be created or destroyed.

Question 3

A diver climbs to the top of a platform and then jumps into the water. Which of the following best describes the energy transformations involved?

Accepted Answer

The diver converts kinetic energy to potential energy while climbing, and potential energy to kinetic energy while diving.

Question 4

Which equation correctly represents the change in free energy for a chemical reaction?

Accepted Answer

$$ \Delta G = \Delta H - T \Delta S $$

Question 5

Which of the following statements about exergonic and endergonic reactions is correct?

Accepted Answer

Exergonic reactions release free energy and have a negative $$\Delta G.$$

Question 6

A cell uses ATP to transport ions against their concentration gradient. Which type of work is being performed?

Accepted Answer

Transport work

Question 7

Which of the following best explains how enzymes speed up chemical reactions?

Accepted Answer

They lower the activation energy ($$E_a) $$required for the reaction to proceed.

Question 8

Which of the following is NOT a way that the active site of an enzyme can lower the activation energy of a reaction?

Accepted Answer

Increasing the temperature of the reaction.

Question 9

A noncompetitive inhibitor decreases the rate of an enzyme-catalyzed reaction by:

Accepted Answer

Binding to a site other than the active site, causing the enzyme to change shape.

Question 10

Which of the following scenarios best illustrates feedback inhibition in a metabolic pathway?

Accepted Answer

The end product of a pathway binds to an enzyme that acts early in the pathway, inhibiting its activity.

Question 11

If a reaction has $$\Delta G \u003c 0$$, which of the following is true?

Accepted Answer

The reaction is exergonic and can occur spontaneously.

Question 12

Which of the following is an example of energy coupling in a cell?

Accepted Answer

Using the energy released from ATP hydrolysis to drive an endergonic reaction.

Question 13

Which of the following best describes the role of ATP in cellular metabolism?

Accepted Answer

ATP couples exergonic and endergonic reactions, providing energy for cellular work.

Question 14

A patient is given a drug that acts as a competitive inhibitor for a key metabolic enzyme. Which of the following would most likely increase the effectiveness of the enzyme despite the presence of the inhibitor?

Accepted Answer

Increasing the concentration of the substrate.

Question 15

Which of the following is a real-world example of the second law of thermodynamics in biological systems?

Accepted Answer

During cellular respiration, some energy is lost as heat, increasing the entropy of the surroundings.

Question 16

Which of the following statements about enzyme catalysis is correct?

Accepted Answer

Enzymes speed up reactions by lowering the activation energy barrier, but do not change $$\Delta G.$$

Question 17

A scientist measures the entropy ($$S) of a $$system before and after a reaction. If the entropy increases, what can be inferred about the disorder of the system?

Accepted Answer

The disorder of the system has increased.

Question 18

Which of the following best describes allosteric regulation of an enzyme?

Accepted Answer

A regulatory molecule binds to a site other than the active site, affecting enzyme function.

Question 19

In a metabolic pathway, what is the likely effect if the enzyme for the first step is inhibited by the end product?

Accepted Answer

The pathway will slow down or stop, preventing overproduction of the end product.

An Introduction to Metabolism (Chapter 8): Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards