Keystone Test Biology: Cell Processes/Transport 3

Question 1

Facilitated diffusion differs from simple diffusion because it requires which of the following?

Accepted Answer

Protein channels or carriers

Answer

Facilitated diffusion uses transport proteins (channels or carriers) to help substances cross the membrane, but still moves substances down their concentration gradient without ATP.

Question 2

During lactic acid fermentation in human muscle cells, what happens to pyruvate?

Accepted Answer

It is converted to lactic acid to regenerate NAD+

Answer

In lactic acid fermentation, pyruvate accepts electrons from NADH and is reduced to lactic acid, regenerating NAD+ so glycolysis can continue.

Question 3

Which of the following BEST describes the function of the sodium-potassium pump?

Accepted Answer

It uses ATP to move 3 Na+ out and 2 K+ into the cell

Answer

The sodium-potassium pump uses ATP to actively transport 3 sodium ions out of and 2 potassium ions into the cell, maintaining the electrochemical gradient.

Question 4

A plant cell placed in a hypertonic solution will undergo plasmolysis. What does this mean?

Accepted Answer

The cell membrane pulls away from the cell wall as water leaves

Answer

Plasmolysis occurs when water exits a plant cell placed in hypertonic solution, causing the cell membrane to shrink and pull away from the rigid cell wall.

Question 5

Which waste product of cellular respiration is removed from the body through the lungs?

Accepted Answer

Carbon dioxide

Answer

Carbon dioxide is produced when carbon atoms from glucose are fully oxidized during the Krebs cycle and is expelled through exhalation.

Keystone Test Practice Test

Keystone Test Practice Test

Keystone Test Biology: Cell Processes/Transport 3