$Rate \ of \ diffusion \propto \text{Concentration \ gradient}$

$Osmolarity = \frac{\text{Number of solute particles}}{\text{Volume of solution}}$

Question 1

Which of the following best describes the plasma membrane's permeability?

Accepted Answer

It is selectively permeable, allowing only certain molecules to cross.

Question 2

Passive transport across the plasma membrane requires:

Accepted Answer

No energy input.

Question 3

Which process involves the movement of water across a selectively permeable membrane?

Accepted Answer

Osmosis

Question 4

A cell is placed in a hypotonic solution. What is the most likely outcome?

Accepted Answer

Water will enter the cell, causing it to swell.

Question 5

Which equation best represents the relationship between rate of diffusion and concentration gradient?

Accepted Answer

$Rate \ of \ diffusion \propto 	ext{Concentration \ gradient}$

Question 6

Which of the following is NOT a type of passive transport?

Accepted Answer

Endocytosis

Question 7

Facilitated diffusion differs from simple diffusion in that:

Accepted Answer

It requires carrier proteins or channels.

Question 8

Which of the following statements about osmosis is correct?

Accepted Answer

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

Question 9

A red blood cell placed in a hypertonic solution will:

Accepted Answer

Shrink due to water leaving the cell.

Question 10

Which of the following is a function of the sodium-potassium pump?

Accepted Answer

It uses ATP to move Na+ out of the cell and K+ into the cell against their concentration gradients.

Question 11

Which formula correctly expresses osmolarity?

Accepted Answer

$Osmolarity = \frac{	ext{Number of solute particles}}{	ext{Volume of solution}}$

Question 12

Which of the following best explains why carrier-mediated facilitated diffusion can become saturated?

Accepted Answer

Carrier proteins are limited in number and can only transport a certain amount of molecules at a time.

Question 13

Which type of channel allows ions to pass through the membrane only when activated by a chemical or electrical signal?

Accepted Answer

Gated channels

Question 14

Which of the following is true regarding active transport?

Accepted Answer

It requires carrier proteins and energy, usually from ATP.

Question 15

A cell uses endocytosis to:

Accepted Answer

Take in large particles, macromolecules, or fluids by engulfing them in vesicles.

Question 16

Which of the following would increase the rate of diffusion across a membrane?

Accepted Answer

Increasing the concentration gradient.

Question 17

If a cell is placed in an isotonic solution, what will happen?

Accepted Answer

There will be no net movement of water.

Question 18

Which of the following is a real-life example of facilitated diffusion?

Accepted Answer

Glucose entering a muscle cell via a protein carrier.

Question 19

Which pressure is responsible for the movement of water into a cell during osmosis?

Accepted Answer

Osmotic pressure

Question 20

Which of the following statements about aquaporins is correct?

Accepted Answer

Aquaporins are channels that facilitate water movement across the membrane.

Cell Membrane Transport: Passive and Active Mechanisms

Study Guide - Practice Questions