Question 1

Which of the following best describes the difference between catabolic and anabolic pathways in cellular metabolism?

Accepted Answer

Catabolic pathways release energy by breaking down complex molecules, while anabolic pathways consume energy to build complex molecules.

Question 2

Which of the following is an example of kinetic energy relevant to biological processes?

Accepted Answer

The movement of muscle contraction.

Question 3

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

Accepted Answer

Energy can be transformed from one form to another, but cannot be created or destroyed.

Question 4

Why can't organisms recycle their energy over and over again, according to the second law of thermodynamics?

Accepted Answer

Because every energy transfer increases the entropy of the universe, making some energy unavailable for work.

Question 5

Which of the following best explains why the metabolism of a cell never reaches equilibrium?

Accepted Answer

Cells constantly exchange materials and energy, maintaining a state of disequilibrium necessary for life.

Question 6

Which molecule is primarily responsible for mediating energy coupling in cells?

Accepted Answer

ATP (adenosine triphosphate)

Question 7

How much energy (in kJ/mol) is typically released by the hydrolysis of ATP to ADP under standard cellular conditions?

Accepted Answer

$$-30.5 \ 	ext{ kJ/mol}$$

Question 8

Which of the following best describes how enzymes lower the activation energy of a reaction?

Accepted Answer

By stabilizing the transition state and providing an alternative reaction pathway.

Question 9

A competitive inhibitor affects an enzyme by:

Accepted Answer

Binding to the active site and blocking substrate binding.

Question 10

Which of the following statements about allosteric regulation is correct?

Accepted Answer

Allosteric regulators bind to sites other than the active site, causing conformational changes that affect enzyme activity.

Question 11

Which of the following best describes the ATP cycle in cells?

Accepted Answer

ATP is synthesized from ADP and $$P_i$$ using energy from catabolic reactions, and hydrolyzed to ADP and $$P_i to $$power cellular work.

Question 12

Which macromolecule class do most enzymes belong to?

Accepted Answer

Proteins

Question 13

Which of the following is an example of feedback inhibition?

Accepted Answer

A product of a metabolic pathway binds to an enzyme early in the pathway, decreasing its activity.

Question 14

Which of the following best explains why the hydrolysis of ATP releases so much energy?

Accepted Answer

The products (ADP and $$P_i) $$are more stable than ATP due to reduced electrostatic repulsion.

Question 15

Which of the following statements about cofactors and coenzymes is correct?

Accepted Answer

Coenzymes are a type of organic cofactor that assist enzymes in catalysis.

Question 16

How does temperature generally affect enzyme activity?

Accepted Answer

Enzyme activity increases with temperature up to an optimum, then decreases as the enzyme denatures.

Question 17

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

Accepted Answer

The enzyme changes shape slightly to fit the substrate more closely upon binding.

Question 18

Which of the following is NOT a type of work performed by cells?

Accepted Answer

Photosynthetic work

Question 19

Which statement best explains why enzymes are organized into complexes or embedded in membranes within cells?

Accepted Answer

To facilitate sequential reactions and increase metabolic efficiency.

Question 20

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

Accepted Answer

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

Study Guide: An Introduction to Metabolism (General Biology, Ch. 6)

Study Guide - Practice Questions