$$\text{Water moves from an area of lower solute concentration to higher solute concentration}$$

$$3\ \text{Na}^+\ \text{out},\ 2\ \text{K}^+\ \text{in}$$

Question 1

Which of the following best describes the amphipathic nature of phospholipids in the plasma membrane?

Accepted Answer

Phospholipids have both hydrophilic and hydrophobic regions, enabling them to form bilayers in aqueous environments.

Question 2

A scientist observes that a cell membrane remains fluid at lower temperatures. Which membrane composition would most likely explain this observation?

Accepted Answer

A high proportion of unsaturated fatty acids in the phospholipids.

Question 3

Which of the following statements about the fluid mosaic model is correct?

Accepted Answer

The membrane is a fluid structure with a mosaic of various proteins embedded in or attached to a bilayer of phospholipids.

Question 4

A red blood cell is placed in a solution and swells until it bursts. Which type of solution was the cell placed in?

Accepted Answer

Hypotonic solution

Question 5

Which of the following is a function of membrane proteins?

Accepted Answer

Facilitating cell-cell recognition

Question 6

What is the main difference between channel proteins and carrier proteins in facilitated diffusion?

Accepted Answer

Channel proteins form hydrophilic tunnels, while carrier proteins change shape to move molecules across the membrane.

Question 7

Which equation best represents the movement of water during osmosis across a selectively permeable membrane?

Accepted Answer

$$	ext{Water moves from an area of lower solute concentration to higher solute concentration}$$

Question 8

A plant cell placed in a hypertonic solution will most likely undergo which process?

Accepted Answer

Plasmolysis, where the plasma membrane pulls away from the cell wall.

Question 9

Which of the following best describes active transport?

Accepted Answer

Movement of substances against their concentration gradient using energy, usually ATP.

Question 10

The sodium-potassium pump is an example of which type of membrane transport?

Accepted Answer

Active transport

Question 11

Which of the following equations correctly represents the net movement of sodium and potassium ions by the sodium-potassium pump?

Accepted Answer

$$3\ 	ext{Na}^+\ 	ext{out},\ 2\ 	ext{K}^+\ 	ext{in}$$

Question 12

Which of the following best explains how an electrogenic pump creates membrane potential?

Accepted Answer

By generating a voltage across the membrane through the unequal movement of positive and negative ions.

Question 13

Which process is responsible for the uptake of cholesterol from the bloodstream into animal cells?

Accepted Answer

Receptor-mediated endocytosis

Question 14

A Paramecium living in freshwater uses a contractile vacuole to maintain water balance. What is the main reason for this adaptation?

Accepted Answer

Freshwater is hypotonic to Paramecium, causing water to enter the cell.

Question 15

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

Accepted Answer

Attachment to the cytoskeleton

Question 16

Which of the following scenarios best illustrates coupled transport (cotransport) in plant cells?

Accepted Answer

A proton pump uses ATP to move $$	ext{H}^+$$ out of the cell, and the resulting gradient drives the uptake of sucrose into the cell.

Question 17

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

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

Question 18

Which of the following is a real-world example of bulk transport via exocytosis?

Accepted Answer

A neuron releasing neurotransmitters into the synaptic cleft.

Question 19

Which of the following best describes the sidedness of membranes?

Accepted Answer

Membranes have distinct inside and outside faces, determined during membrane synthesis by the ER and Golgi apparatus.

Chapter 7: Membrane Structure and Function – Study Notes

Study Guide - Practice Questions