Question 1

Which statement best describes the First Law of Thermodynamics as it applies to biological systems?

Accepted Answer

Energy can be transferred, transformed, or acted upon, but cannot be created or destroyed.

Question 2

During the breakdown of glucose in glycolysis, which of the following statements about potential energy is correct?

Accepted Answer

The reactant (glucose) has higher potential energy than the product (pyruvate).

Question 3

Which of the following best explains why breaking molecular bonds in a chemical reaction requires energy?

Accepted Answer

Energy is required to overcome the stability of the bonds holding atoms together.

Question 4

Consider the Second Law of Thermodynamics. What happens to the entropy of the universe during a chemical reaction that releases energy?

Accepted Answer

Entropy of the universe increases.

Question 5

Which of the following reactions is most likely to be spontaneous?

Accepted Answer

A reaction with a negative change in Gibbs free energy ($$\Delta G \u003c 0).$$

Question 6

If a metabolic reaction requires energy input and the products are less stable than the reactants, what type of pathway is this?

Accepted Answer

Anabolic pathway

Question 7

Which of the following best describes the role of ATP hydrolysis in coupling non-spontaneous reactions?

Accepted Answer

ATP hydrolysis releases energy, which can be used to drive non-spontaneous reactions.

Question 8

How many molecules of ATP (each releasing 7.3 kcal/mol upon hydrolysis) are required to make a reaction with $$\Delta G = 30$$ kcal/mol proceed spontaneously?

Accepted Answer

5

Question 9

Which of the following statements about enzymes is correct?

Accepted Answer

Enzymes decrease the activation energy, making reactions proceed faster.

Question 10

A competitive inhibitor affects an enzyme by:

Accepted Answer

Binding to the active site, preventing substrate binding.

Question 11

Which of the following best describes entropy?

Accepted Answer

Entropy is a measure of randomness or disorder.

Question 12

During protein synthesis, amino acids are joined by peptide bonds to form a polypeptide. What is true about the change in Gibbs free energy ($$\Delta G) $$for this process?

Accepted Answer

$$\Delta G is $$positive, and the process requires energy input.

Question 13

Which of the following is an example of an exergonic reaction in biological systems?

Accepted Answer

Hydrolysis of ATP to ADP and inorganic phosphate.

Question 14

If the entropy of a system decreases, what must happen to the entropy of the surroundings according to the Second Law of Thermodynamics?

Accepted Answer

The entropy of the surroundings must increase to a greater extent.

Question 15

Which of the following statements about metabolic pathways is correct?

Accepted Answer

Anabolic pathways build complex molecules and require energy input.

Question 16

What is the main reason organisms metabolize?

Accepted Answer

To carry out chemical reactions necessary for survival, such as growth and reproduction.

Question 17

Which of the following is true about noncompetitive inhibitors?

Accepted Answer

They bind to an allosteric site, changing the enzyme's shape and preventing substrate binding.

Question 18

Which of the following best describes the energy change when stable molecules like $$\mathrm{H_2O}$$ are formed from $$\mathrm{H_2$}$$ and $$\mathrm{O_2$}$$?

Accepted Answer

Energy is released when the bonds are formed.

Question 19

Which of the following is NOT a requirement for enzyme function?

Accepted Answer

Competitive inhibitor binding to the active site.

Energy, Thermodynamics, and Metabolism in Biological Systems

Study Guide - Practice Questions

Study Guide - Flashcards