$$C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{energy}$$

Question 1

Which of the following best describes the role of a signal transduction pathway in a multicellular organism?

Accepted Answer

It allows cells to communicate with each other by transmitting signals from receptors to target molecules inside the cell.

Question 2

A mutation causes a cell surface receptor to be unable to bind its ligand. What is the most likely consequence?

Accepted Answer

The cell will not initiate the signal transduction pathway in response to the ligand.

Question 3

Which equation correctly represents the summary reaction for cellular respiration?

Accepted Answer

$$C_6H_{12}O_6$ + 6O_2 ightarrow 6CO_2 + 6H_2O + 	ext{energy}$$

Question 4

Which of the following best explains why enzymes are highly specific for their substrates?

Accepted Answer

The three-dimensional shape of the enzyme's active site matches the substrate.

Question 5

Which process in cellular respiration produces the most ATP?

Accepted Answer

Oxidative phosphorylation (electron transport chain and chemiosmosis)

Question 6

If a poison blocks the enzyme ATP synthase, which process will be directly affected?

Accepted Answer

Chemiosmosis

Question 7

Which of the following statements about competitive inhibition is correct?

Accepted Answer

A competitive inhibitor binds to the active site of an enzyme, preventing substrate binding.

Question 8

Which of the following best describes the energy transformation during photosynthesis?

Accepted Answer

Light energy is converted into chemical energy stored in glucose.

Question 9

Which molecule acts as the final electron acceptor in the electron transport chain of aerobic respiration?

Accepted Answer

Oxygen ($$O_2)$$

Question 10

A cell is exposed to a toxin that disrupts the citric acid cycle. Which of the following would most likely decrease as a result?

Accepted Answer

Production of NADH and FADH$$_2$$

Question 11

Which of the following is an example of feedback inhibition in a metabolic pathway?

Accepted Answer

The end product of a pathway inhibits an enzyme that acts early in the pathway.

Question 12

Which of the following best explains why temperature and pH affect enzyme activity?

Accepted Answer

They alter the three-dimensional structure of the enzyme, affecting the active site.

Question 13

Which of the following is a correct description of substrate-level phosphorylation?

Accepted Answer

A phosphate group is directly transferred from a substrate to ADP to form ATP.

Question 14

Which of the following is a primary function of the Calvin cycle in photosynthesis?

Accepted Answer

To convert carbon dioxide into glucose

Question 15

Which of the following best describes the difference between fermentation and aerobic respiration?

Accepted Answer

Fermentation does not use oxygen and produces less ATP than aerobic respiration.

Question 16

Which of the following is true about the role of NADH in cellular respiration?

Accepted Answer

NADH donates electrons to the electron transport chain, helping to generate ATP.

Question 17

Which of the following best explains why ATP is considered the energy currency of the cell?

Accepted Answer

ATP stores energy in its phosphate bonds, which can be used to power cellular work.

Question 18

Which of the following is a real-world example of an enzyme-catalyzed reaction?

Accepted Answer

The breakdown of lactose into glucose and galactose by lactase in the human intestine.

Question 19

Which of the following best describes the main function of the light-dependent reactions of photosynthesis?

Accepted Answer

To generate ATP and NADPH for use in the Calvin cycle

Question 20

Which of the following statements about allosteric regulation of enzymes is correct?

Accepted Answer

An allosteric regulator binds to a site other than the active site, changing the enzyme's activity.

Metabolism, Cellular Energetics, and Membrane Transport: Study Guide

Study Guide - Practice Questions