Question 1

Which of the following best describes the role of cholesterol in the plasma membrane?

Accepted Answer

It increases membrane fluidity at low temperatures and decreases it at high temperatures.

Question 2

A red blood cell is placed in a hypotonic solution. What will most likely happen to the cell, and why?

Accepted Answer

It will burst because water will move into the cell by osmosis.

Question 3

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

It involves carrier or channel proteins to move substances down their concentration gradient.

Question 4

A cell is exposed to a toxin that blocks the function of all carrier proteins. Which process would be most directly affected?

Accepted Answer

Facilitated diffusion of glucose into the cell

Question 5

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

Accepted Answer

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

Question 6

Which of the following best describes the second law of thermodynamics as it applies to biological systems?

Accepted Answer

Every energy transfer increases the entropy of the universe.

Question 7

A metabolic pathway is regulated by feedback inhibition. Which of the following best explains this process?

Accepted Answer

The end product of the pathway binds to an allosteric site on the first enzyme, decreasing its activity.

Question 8

Which of the following is an example of primary active transport?

Accepted Answer

Pumping of sodium ions out of a cell by the Na+/K+ ATPase using ATP

Question 9

Which of the following best describes the difference between competitive and noncompetitive enzyme inhibition?

Accepted Answer

Competitive inhibitors bind to the active site, while noncompetitive inhibitors bind to a different site on the enzyme.

Question 10

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 quickly released to drive cellular processes.

Question 11

During oxidative phosphorylation, which process directly produces ATP?

Accepted Answer

The movement of protons through ATP synthase down their electrochemical gradient

Question 12

Which of the following statements about chemiosmosis is correct?

Accepted Answer

Chemiosmosis uses a proton gradient to drive the synthesis of ATP.

Question 13

Which of the following best describes the function of integral proteins in the plasma membrane?

Accepted Answer

They span the membrane and are involved in transport and cell signaling.

Question 14

A scientist measures the rate of an enzyme-catalyzed reaction at different substrate concentrations and plots the data. The curve levels off at high substrate concentrations. What is the most likely explanation?

Accepted Answer

The enzyme has become saturated; all active sites are occupied.

Question 15

Which of the following is true about the difference between endergonic and exergonic reactions?

Accepted Answer

Endergonic reactions have a positive $$\Delta G$$, while exergonic reactions have a negative $$\Delta G.$$

Question 16

Which of the following best describes the function of a coenzyme in an enzymatic reaction?

Accepted Answer

A coenzyme is a non-protein organic molecule that assists in enzyme function.

Question 17

Which of the following is an example of a redox reaction in cellular respiration?

Accepted Answer

The transfer of electrons from NADH to the electron transport chain

Question 18

Which of the following best explains the difference between substrate-level phosphorylation and oxidative phosphorylation?

Accepted Answer

Substrate-level phosphorylation directly transfers a phosphate group to ADP from a substrate, while oxidative phosphorylation uses a proton gradient to drive ATP synthesis.

Question 19

Which of the following best describes the function of glycoproteins in the plasma membrane?

Accepted Answer

They are involved in cell recognition and signaling.

Question 20

Which of the following statements about NAD and FAD is correct?

Accepted Answer

NAD and FAD are electron carriers that exist in oxidized and reduced forms.

Cell Membranes, Transport, Energy, and Enzyme Regulation: General Biology Study Guide

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