Question 1

Which of the following best describes the monomer that makes up enzymes?

Accepted Answer

Amino acids

Question 2

What is the primary effect of an enzyme on the activation energy of a biological reaction?

Accepted Answer

It decreases the activation energy required for the reaction.

Question 3

Which of the following environmental changes is most likely to cause irreversible denaturation of an enzyme?

Accepted Answer

Extreme heat

Question 4

A competitive inhibitor affects enzyme activity by:

Accepted Answer

Binding to the active site and preventing substrate binding

Question 5

Which formula correctly relates pH to hydrogen ion concentration?

Accepted Answer

$$pH = -\log_{10}[H^+]$$

Question 6

During cellular respiration, which molecule is the final electron acceptor in the electron transport chain?

Accepted Answer

Oxygen ($$O_2)$$

Question 7

Which process in photosynthesis is responsible for the production of ATP?

Accepted Answer

Light-dependent reactions

Question 8

How does a noncompetitive inhibitor affect enzyme activity?

Accepted Answer

It binds to an allosteric site, changing the enzyme's shape and reducing function.

Question 9

Which statement best describes the first law of thermodynamics as it applies to living organisms?

Accepted Answer

Energy is transferred and transformed, but not created or destroyed.

Question 10

What is the main function of fermentation in cells?

Accepted Answer

To regenerate NAD+ for glycolysis

Question 11

Which of the following is a product of glycolysis?

Accepted Answer

Pyruvate

Question 12

How does variation in the number and types of molecules within cells affect an organism's fitness?

Accepted Answer

It increases the organism's ability to survive and reproduce in different environments.

Question 13

Which of the following best explains why enzymes do not change the Gibbs Free Energy ($$\Delta G) of a $$reaction?

Accepted Answer

Enzymes lower the activation energy but do not affect the overall energy change.

Question 14

Which of the following is true about the relationship between the light reactions and the Calvin cycle in photosynthesis?

Accepted Answer

The light reactions provide ATP and NADPH for the Calvin cycle.

Question 15

What is the effect of increasing substrate concentration on the rate of an enzyme-catalyzed reaction, assuming enzyme concentration is constant?

Accepted Answer

The reaction rate will increase until the enzyme becomes saturated.

Question 16

Which process generates the proton gradient used to synthesize ATP in cellular respiration?

Accepted Answer

Electron transport chain

Question 17

Which of the following is an example of oxidative phosphorylation?

Accepted Answer

ATP synthesis using the proton gradient in mitochondria

Question 18

If the pH of a solution decreases from 7 to 5, how does the concentration of hydrogen ions change?

Accepted Answer

It increases by 100 times

Question 19

Which of the following statements about metabolic pathways is correct?

Accepted Answer

Products of one reaction often serve as reactants for the next step.

Question 20

Which molecule is produced during the light-dependent reactions of photosynthesis and used in the Calvin cycle?

Accepted Answer

ATP

Unit 3: Cellular Energetics – Enzymes, Energy, Photosynthesis, and Cellular Respiration

Study Guide - Practice Questions