Question 1

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

Accepted Answer

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

Question 2

A plant uses light energy to synthesize glucose from carbon dioxide and water. Which type of metabolic pathway does this process represent?

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 best explains why living organisms do not violate the second law of thermodynamics?

Accepted Answer

They increase the entropy of their surroundings through metabolic processes.

Question 5

A reaction has $$\Delta G = -10$$ 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 is an example of energy coupling in a cell?

Accepted Answer

The hydrolysis of ATP drives the synthesis of glutamine from glutamic acid and ammonia.

Question 7

Which of the following statements about enzymes is correct?

Accepted Answer

Enzymes lower the activation energy barrier, allowing reactions to occur more rapidly.

Question 8

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

Accepted Answer

Binding to the active site and preventing substrate binding.

Question 9

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

Accepted Answer

ATP couples exergonic and endergonic reactions by transferring a phosphate group.

Question 10

Which of the following environmental changes is most likely to denature an enzyme found in the human stomach?

Accepted Answer

Raising the pH from 2 to 8

Question 11

Which of the following is true about the ATP cycle in cells?

Accepted Answer

ATP is regenerated from ADP and inorganic phosphate using energy from catabolic reactions.

Question 12

Which of the following is an example of a catabolic pathway?

Accepted Answer

Breakdown of proteins into amino acids

Question 13

Which of the following best explains why increasing substrate concentration can overcome competitive inhibition but not noncompetitive inhibition?

Accepted Answer

Competitive inhibitors compete with the substrate for the active site, while noncompetitive inhibitors bind elsewhere and change enzyme shape.

Question 14

Which of the following is NOT a form of energy relevant to biological systems?

Accepted Answer

Nuclear energy

Question 15

A reaction in a cell has $$\Delta G = +5$$ kcal/mol. Which of the following statements is true?

Accepted Answer

The reaction is endergonic and requires an input of energy.

Question 16

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 17

Which of the following is a correct statement about the effect of temperature on enzyme activity?

Accepted Answer

Each enzyme has an optimal temperature, above which activity decreases due to denaturation.

Question 18

Which of the following is an example of mechanical work powered by ATP in a cell?

Accepted Answer

Contraction of a muscle cell

Question 19

Which of the following statements about cofactors is correct?

Accepted Answer

Cofactors can be inorganic ions or organic molecules called coenzymes.

Question 20

Which of the following best describes the relationship between free energy, stability, and equilibrium in a biological system?

Accepted Answer

Systems tend to move toward lower free energy, becoming more stable and reaching equilibrium.

Chapter 8: An Introduction to Metabolism – Study Notes

Study Guide - Practice Questions