Question 1

Which of the following best describes the fluid mosaic model of the plasma membrane?

Accepted Answer

A fluid phospholipid bilayer with proteins embedded or attached, allowing lateral movement of components.

Question 2

Which function is NOT performed by membrane proteins?

Accepted Answer

Storing genetic information for the cell.

Question 3

A red blood cell is placed in a solution and begins to shrink. Which term best describes the solution?

Accepted Answer

Hypertonic

Question 4

Which of the following molecules would most easily diffuse across a plasma membrane without the help of a transport protein?

Accepted Answer

Oxygen ($$O_2)$$

Question 5

Which process requires energy input from ATP to move substances across the plasma membrane?

Accepted Answer

Active transport

Question 6

A cell engulfs a bacterium by wrapping its membrane around it and forming a vesicle. This process is called:

Accepted Answer

Phagocytosis

Question 7

Which statement about osmosis is correct?

Accepted Answer

Osmosis is the diffusion of water across a selectively permeable membrane.

Question 8

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

Accepted Answer

The active site of an enzyme has a unique shape that fits only specific substrates.

Question 9

A competitive inhibitor decreases the rate of an enzyme-catalyzed reaction by:

Accepted Answer

Binding to the active site and preventing substrate binding.

Question 10

Which of the following is an example of energy transformation in a biological system?

Accepted Answer

The conversion of glucose to ATP during cellular respiration.

Question 11

Which law of thermodynamics states that energy cannot be created or destroyed?

Accepted Answer

First law of thermodynamics

Question 12

Which of the following reactions is exergonic?

Accepted Answer

The breakdown of glucose during cellular respiration

Question 13

How does ATP typically drive endergonic reactions in cells?

Accepted Answer

By donating a phosphate group to another molecule

Question 14

Which of the following best describes feedback inhibition?

Accepted Answer

A process where the end product of a metabolic pathway inhibits an enzyme involved earlier in the pathway.

Question 15

Which of the following is a real-world example of receptor-mediated endocytosis?

Accepted Answer

A liver cell taking in cholesterol via LDL particles.

Question 16

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

It uses transport proteins to move substances down their concentration gradient.

Question 17

Which of the following best explains why extreme heat can inhibit enzyme function?

Accepted Answer

Heat changes the enzyme's shape, preventing substrate binding.

Question 18

Which of the following is true about aquaporins?

Accepted Answer

They are protein channels that facilitate rapid water movement across membranes.

Question 19

A scientist adds a noncompetitive inhibitor to an enzyme reaction. What is the most likely result?

Accepted Answer

The inhibitor binds elsewhere on the enzyme, changing its shape and reducing activity.

Question 20

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

Accepted Answer

They act as ID tags that may be recognized by other cells.

Chapter 5: The Working Cell – Membrane Structure, Function, and Cellular Energy

Study Guide - Practice Questions