Question 1

Which of the following best describes the second law of thermodynamics as it applies to biological systems?

Accepted Answer

Every energy transfer or transformation increases the entropy of the universe.

Question 2

A cell synthesizes a protein from amino acids. This process is an example of which type of metabolic pathway?

Accepted Answer

Anabolic pathway

Question 3

Which of the following equations correctly represents the change in free energy ($$\Delta G) $$for a chemical reaction?

Accepted Answer

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

Question 4

Which of the following statements about ATP is FALSE?

Accepted Answer

ATP hydrolysis is an endergonic reaction under cellular conditions.

Question 5

A reaction has $$\Delta G = -7.3$$ kcal/mol. Which of the following is true about this reaction?

Accepted Answer

It is spontaneous and releases free energy.

Question 6

Which of the following best explains why enzymes are necessary for metabolic reactions in living organisms?

Accepted Answer

Enzymes lower the activation energy ($$E_A) $$required for reactions to proceed.

Question 7

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

Accepted Answer

The hydrolysis of ATP is used to drive the synthesis of glutamine from glutamic acid and ammonia.

Question 8

Which of the following would most likely increase the rate of an enzyme-catalyzed reaction?

Accepted Answer

Increasing the substrate concentration.

Question 9

Which of the following statements about competitive and noncompetitive enzyme inhibitors is correct?

Accepted Answer

Competitive inhibitors resemble the substrate and bind to the active site.

Question 10

A patient is diagnosed with a deficiency in a vitamin that acts as a coenzyme. Which of the following is the most likely consequence?

Accepted Answer

The patient's enzymes will have reduced catalytic activity.

Question 11

Which of the following best describes the induced fit model of enzyme function?

Accepted Answer

The enzyme changes shape slightly to fit more snugly around the substrate.

Question 12

Which of the following is a real-life example of an exergonic reaction?

Accepted Answer

The breakdown of glucose during cellular respiration.

Question 13

Which of the following statements about entropy is correct?

Accepted Answer

Entropy is a measure of molecular disorder or randomness.

Question 14

A scientist adds a noncompetitive inhibitor to an enzyme-catalyzed reaction. What is the most likely effect?

Accepted Answer

The inhibitor binds to a site other than the active site and decreases enzyme activity.

Question 15

Which of the following best explains why the hydrolysis of ATP is used to drive endergonic reactions in cells?

Accepted Answer

ATP hydrolysis is a highly exergonic reaction, providing energy to make endergonic reactions energetically favorable.

Question 16

Which of the following is NOT a type of cellular work powered by ATP?

Accepted Answer

Passive diffusion of gases across a membrane.

Question 17

Which of the following statements about metabolic pathways is correct?

Accepted Answer

Metabolic pathways involve a series of enzyme-catalyzed reactions that transform a specific molecule into a product.

Question 18

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

Accepted Answer

Cofactors are nonprotein helpers that are required for some enzymes to function.

Question 19

A reaction in a cell has a positive $$\Delta G. $$Which of the following statements is true?

Accepted Answer

The reaction is nonspontaneous and requires an input of energy.

Question 20

Which of the following is a correct statement about the relationship between free energy and stability?

Accepted Answer

Systems tend to change in a way that decreases their free energy, becoming more stable.

Chapter 8: An Introduction to Metabolism – Study Notes

Study Guide - Practice Questions