Question 1

Which process is depicted in the first image, and what is its primary function in the cell?

Accepted Answer

Exocytosis; it enables the cell to expel large molecules or waste products by fusing vesicles with the plasma membrane.

Question 2

According to the fluid mosaic model, which statement best describes the structure of cellular membranes?

Accepted Answer

Membranes are dynamic, with amphipathic proteins embedded in a fluid phospholipid bilayer.

Question 3

What role does cholesterol play in the plasma membrane?

Accepted Answer

It helps membranes resist changes in fluidity caused by temperature shifts.

Question 4

Which of the following best explains why hydrophobic substances pass through the plasma membrane more easily than hydrophilic substances?

Accepted Answer

Hydrophobic substances are soluble in lipids and can diffuse through the membrane.

Question 5

Refer to the second image. What is the main difference between channel proteins and carrier proteins in facilitated diffusion?

Accepted Answer

Channel proteins provide a continuous passage, while carrier proteins change shape to move molecules.

Question 6

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

Accepted Answer

It will shrink because water leaves the cell to balance solute concentrations.

Question 7

Which equation best represents the movement of water during osmosis?

Accepted Answer

$$\Delta \Psi = \Psi_s + \Psi_p$$

Question 8

In the third image, what is the source of energy for the process shown, and what is the process called?

Accepted Answer

ATP; active transport

Question 9

Why is cotransport considered a form of active transport even though ATP is not directly used by the cotransporter?

Accepted Answer

Because the energy for uphill transport comes from the downhill movement of another solute, which was established by ATP-dependent pumps.

Question 10

Which type of endocytosis involves the binding of specific molecules to receptors on the cell surface?

Accepted Answer

Receptor-mediated endocytosis

Question 11

Which of the following best describes selective permeability of the plasma membrane?

Accepted Answer

The membrane allows some substances to cross more easily than others.

Question 12

What is the main function of glycoproteins and glycolipids on the exterior side of the plasma membrane?

Accepted Answer

They interact with surface molecules of other cells for cell-cell recognition.

Question 13

Which of the following scenarios is an example of bulk transport?

Accepted Answer

A vesicle fusing with the plasma membrane to release hormones.

Question 14

Which of the following is NOT a function of membrane proteins?

Accepted Answer

DNA replication

Question 15

A cell is placed in an isotonic solution. What will happen to the net movement of water?

Accepted Answer

There will be no net movement of water.

Question 16

Which of the following best explains why aquaporins are important for cells?

Accepted Answer

They allow rapid movement of water across the membrane, increasing permeability.

Question 17

Which of the following equations best represents the electrochemical gradient for an ion?

Accepted Answer

$$\Delta G = RT \ln \left( \frac{[C]_2}{[C]_1} \right) + zF\Delta \Psi$$

Membrane Structure and Function: Chapter 7 Review

Study Guide - Practice Questions