Question 1

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

Accepted Answer

They have both hydrophilic heads and hydrophobic tails, allowing them to form a bilayer with tails facing inward and heads facing outward.

Question 2

A red blood cell is placed in a solution and begins to swell and eventually bursts. Which of the following best explains what type of solution the cell was placed in and the direction of water movement?

Accepted Answer

The cell was placed in a hypotonic solution, and water moved into the cell.

Question 3

Which of the following statements about membrane fluidity is correct?

Accepted Answer

Membranes with a higher proportion of unsaturated fatty acids remain more fluid at lower temperatures.

Question 4

Which of the following molecules is most likely to diffuse directly through the lipid bilayer of a plasma membrane without the aid of a transport protein?

Accepted Answer

Oxygen ($$O_2)$$

Question 5

A plant cell is placed in a hypertonic solution. What is the most likely outcome for the cell?

Accepted Answer

The cell will lose water, and the plasma membrane will pull away from the cell wall (plasmolysis).

Question 6

Which of the following best explains how the sodium-potassium pump creates membrane potential in animal cells?

Accepted Answer

It actively transports $$3$$ $$Na^+$$ ions out of the cell and $$2$$ $$K^+$$ ions into the cell, creating a net negative charge inside.

Question 7

Which of the following is an example of active transport?

Accepted Answer

The movement of $$Na^+$$ ions against their concentration gradient using ATP.

Question 8

A cell is placed in an isotonic solution. Which of the following best describes the movement of water?

Accepted Answer

Water moves in and out of the cell at equal rates, resulting in no net movement.

Question 9

Which of the following best describes receptor-mediated endocytosis?

Accepted Answer

It is a process in which specific molecules bind to receptors on the cell surface, triggering vesicle formation to bring those molecules into the cell.

Question 10

Which of the following is a function of membrane carbohydrates?

Accepted Answer

They serve as markers for cell recognition, often attached to proteins (glycoproteins) or lipids (glycolipids).

Question 11

Which of the following best explains why ions such as $$Na^+$$ and $$K^+$$ cannot easily cross the plasma membrane without assistance?

Accepted Answer

The hydrophobic interior of the lipid bilayer repels charged particles, preventing their diffusion.

Question 12

Which of the following scenarios best illustrates cotransport in biological membranes?

Accepted Answer

The active transport of $$H^+$$ ions out of a plant cell creates a gradient that drives the uptake of sucrose into the cell via a cotransporter.

Question 13

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

It requires transport proteins but does not require energy input.

Question 14

A patient with familial hypercholesterolemia has high blood cholesterol because:

Accepted Answer

Their cells lack functional LDL receptor proteins, so cholesterol cannot be taken up by receptor-mediated endocytosis.

Question 15

Which of the following best describes the effect of cholesterol on membrane fluidity at different temperatures?

Accepted Answer

At high temperatures, cholesterol reduces membrane fluidity; at low temperatures, it prevents solidification by disrupting packing of phospholipids.

Question 16

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

Accepted Answer

Synthesizing DNA from RNA templates.

Question 17

Which of the following best explains why plant cells become turgid in hypotonic solutions?

Accepted Answer

Water enters the cell, and the cell wall exerts turgor pressure, preventing excessive swelling.

Question 18

Which of the following best describes the difference between channel proteins and carrier proteins in facilitated diffusion?

Accepted Answer

Channel proteins provide a hydrophilic tunnel for molecules to pass through, while carrier proteins change shape to move molecules across the membrane.

Question 19

A cell uses exocytosis to secrete insulin. Which of the following best describes this process?

Accepted Answer

Vesicles containing insulin fuse with the plasma membrane, releasing insulin outside the cell.

Membrane Structure and Function – Study Notes (Campbell Biology, Chapter 7)

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드