Question 1

Which of the following best describes the structure of a phospholipid bilayer in a plasma membrane?

Accepted Answer

Hydrophilic heads face outward toward water, and hydrophobic tails face inward away from water.

Question 2

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

Accepted Answer

It will swell and may burst due to water entering the cell.

Question 3

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

It requires transport proteins but does not require energy.

Question 4

What is the main function of aquaporins in the plasma membrane?

Accepted Answer

To increase the rate of water transport across the membrane.

Question 5

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

Accepted Answer

Water enters the cell, causing the protoplast to press against the cell wall, generating turgor pressure.

Question 6

Which of the following is an example of active transport?

Accepted Answer

The sodium-potassium pump moving Na$$^+$$ out of and K$$^+$$ into the cell using ATP.

Question 7

A plant cell is placed in a hypertonic solution. What process occurs and what is the result?

Accepted Answer

Plasmolysis occurs; the protoplast shrinks away from the cell wall.

Question 8

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

Accepted Answer

It helps maintain membrane fluidity at different temperatures.

Question 9

Which of the following statements about selective permeability is correct?

Accepted Answer

Hydrophobic molecules pass through the membrane more easily than hydrophilic molecules.

Question 10

Which of the following is true about cotransport in plant cells?

Accepted Answer

A proton gradient created by ATP-powered pumps is used to drive the uptake of sucrose against its concentration gradient.

Question 11

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

Accepted Answer

Channel proteins form hydrophilic tunnels, while carrier proteins change shape to move substances.

Question 12

A cell is placed in an isotonic solution. What will happen to the cell's volume?

Accepted Answer

It will remain unchanged because water moves in and out at equal rates.

Question 13

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

Accepted Answer

Synthesis of DNA.

Question 14

Which equation best represents the movement of water during osmosis?

Accepted Answer

$$	ext{Water moves from a region of lower solute concentration to a region of higher solute concentration}$$

Question 15

Which of the following scenarios best illustrates the concept of tonicity?

Accepted Answer

A freshwater protozoan placed in saltwater shrivels as water leaves its cell.

Question 16

Which of the following statements about passive transport is correct?

Accepted Answer

It does not require energy and moves substances down their concentration gradient.

Question 17

Which of the following best explains why glucose carrier proteins do not transport fructose?

Accepted Answer

Transport proteins are specific to the molecules they transport due to their shape.

Question 18

Which of the following is a real-life example of bulk transport?

Accepted Answer

White blood cells engulfing bacteria by endocytosis.

Question 19

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

Accepted Answer

They are involved in cell-cell recognition.

Question 20

A plant cell is observed under a microscope after being placed in a hypertonic solution. Which of the following would you expect to see?

Accepted Answer

The protoplast has shrunk away from the cell wall (plasmolysis).

Membrane Structure and Function: Transport Mechanisms in Cells

Study Guide - Practice Questions