Question 1

Which of the following best describes the process illustrated in the first image, where a dye is dropped into water and gradually spreads throughout the beaker?

Accepted Answer

Simple diffusion, where molecules move from an area of high concentration to low concentration

Question 2

According to the permeability scale in the second image, which molecule would diffuse most rapidly across a typical cell membrane?

Accepted Answer

$$O_2$$

Question 3

In the third image, what is the primary force responsible for the movement of water across the selectively permeable membrane?

Accepted Answer

Osmotic pressure

Question 4

Which of the following best explains why the Na^+/K^+ pump (shown in the fourth image) is considered an example of active transport?

Accepted Answer

It requires ATP to move ions against their concentration gradients

Question 5

What is the main function of the sodium-potassium pump in maintaining the resting membrane potential, as shown in the fifth image?

Accepted Answer

It pumps 3 Na^+ out and 2 K^+ in, maintaining a negative charge inside

Question 6

Based on the sixth image, what would happen to the membrane potential if the plasma membrane were freely permeable to K^+?

Accepted Answer

The membrane potential would reach the K^+ equilibrium potential (about -90 mV)

Question 7

In the seventh image, what is the net effect of the combined chemical and electrical gradients for Na^+ at the resting membrane potential?

Accepted Answer

Na^+ moves into the cell

Question 8

Which type of gated ion channel, as shown in the eighth image, opens in response to the binding of a neurotransmitter such as acetylcholine?

Accepted Answer

Chemically gated ion channel

Question 9

During the depolarization phase shown in the ninth image, what happens to the membrane potential?

Accepted Answer

It becomes less negative (moves toward zero)

Question 10

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

Accepted Answer

The cell will swell and may burst due to water influx

Question 11

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

It requires a transport protein and moves substances down their concentration gradient

Question 12

If a cell is placed in a hypertonic solution, which direction will water move and what is the likely result?

Accepted Answer

Water will move out of the cell, causing it to shrink

Question 13

Which of the following best describes the electrochemical gradient?

Accepted Answer

It is the sum of the chemical and electrical gradients acting on an ion

Question 14

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

Accepted Answer

Increasing the concentration gradient

Question 15

A neuron is at rest with a membrane potential of $$-70\ \mathrm{mV}. $$Which ion is most responsible for maintaining this resting potential?

Accepted Answer

K^+

Question 16

Which of the following is true about the movement of ions through gated channels?

Accepted Answer

Ions move through gated channels only when the channels are open

Question 17

Which equation best represents the Nernst equation for calculating the equilibrium potential ($$E_{ion}) $$for a particular ion?

Accepted Answer

$$E_{ion} = \frac{RT}{zF} \ln \left( \frac{[ion]_{outside}}{[ion]_{inside}} \right)$$

Question 18

Which of the following best describes cotransport (symport) in carrier-mediated transport?

Accepted Answer

One substance is transported down its gradient, providing energy for another to move against its gradient in the same direction

Question 19

A cell is exposed to a toxin that blocks all ATP production. Which of the following transport processes would be most directly affected?

Accepted Answer

Active transport of Na^+ and K^+

Question 20

Which of the following scenarios best illustrates secondary active transport?

Accepted Answer

Na^+ is pumped out of the cell using ATP, and glucose is transported into the cell along with Na^+ without direct ATP use

Membrane Transport, Membrane Potential, & Bioelectricity: Study Guide for Human Anatomy and Physiology I

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