Question 1

Which of the following best describes the difference between kinetic and potential energy in a biological system?

Accepted Answer

Kinetic energy is the energy of motion, while potential energy is stored energy due to position or structure.

Question 2

According to the first law of thermodynamics, which statement is correct regarding energy in living systems?

Accepted Answer

Energy is conserved; it can change forms but is neither created nor destroyed.

Question 3

Which equation correctly represents the change in Gibbs free energy ($$\Delta G) $$for a chemical reaction?

Accepted Answer

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

Question 4

A reaction has $$\Delta G \u003c 0. $$What does this indicate about the reaction?

Accepted Answer

The reaction is exergonic and occurs spontaneously.

Question 5

Which of the following is true about the second law of thermodynamics in biological systems?

Accepted Answer

Every energy conversion increases the disorder (entropy) of the universe.

Question 6

In a redox reaction, which molecule is oxidized?

Accepted Answer

The molecule that loses electrons.

Question 7

What is the primary role of ATP in cellular metabolism?

Accepted Answer

Short-term energy currency used to power cellular work.

Question 8

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

Accepted Answer

Color of the substrate.

Question 9

How does a competitive inhibitor affect enzyme activity?

Accepted Answer

It binds to the active site, preventing substrate binding.

Question 10

Which statement best explains why enzymes are considered biological catalysts?

Accepted Answer

They speed up reactions by lowering the activation energy without being consumed.

Question 11

A cell is exposed to a non-competitive inhibitor. What is the most likely effect on the enzyme?

Accepted Answer

The inhibitor binds elsewhere, changing the enzyme's shape and reducing activity.

Question 12

Which of the following best describes feedback inhibition in a biochemical pathway?

Accepted Answer

The end product of a pathway inhibits an enzyme earlier in the pathway.

Question 13

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

Accepted Answer

Genetic work, such as DNA replication.

Question 14

If a reaction has $$\Delta G \u003e 0$$, which of the following is true?

Accepted Answer

The reaction is endergonic and requires energy input.

Question 15

Which process directly couples the hydrolysis of ATP to cellular work?

Accepted Answer

ATP hydrolysis releases energy that is used to drive endergonic reactions.

Question 16

Which of the following scenarios best illustrates the second law of thermodynamics in a living system?

Accepted Answer

A muscle cell produces heat as a byproduct during contraction.

Question 17

Which of the following statements about enzyme specificity is correct?

Accepted Answer

Enzymes are highly specific, usually catalyzing only one type of reaction for a particular substrate.

Question 18

Which of the following is a real-world example of an exergonic reaction in cells?

Accepted Answer

Hydrolysis of ATP to ADP and P$$_i.$$

Question 19

Which statement best explains why cells do not store large amounts of ATP?

Accepted Answer

ATP is unstable and is rapidly hydrolyzed, so cells only maintain a small supply.

Energetics of Living Systems: Energy, Thermodynamics, and Enzymes

Study Guide - Practice Questions