Question 1

Which of the following molecules is most likely to cross the plasma membrane via simple diffusion?

Accepted Answer

Oxygen (O$$_2)$$

Question 2

A cell is placed in a hypertonic solution. What will happen to the cell?

Accepted Answer

It will lose water and shrink.

Question 3

Which statement best describes facilitated diffusion?

Accepted Answer

It uses membrane proteins to move substances down their concentration gradient without energy input.

Question 4

The sodium-potassium pump moves ions across the membrane using the following stoichiometry:

Accepted Answer

$$3\ \mathrm{Na}^+$$\ out, $$2\ \mathrm{K}^+$$\ in$

Question 5

Which of the following best explains why water can move rapidly across cell membranes?

Accepted Answer

Water uses aquaporin channels for facilitated diffusion.

Question 6

A cell uses a glucose co-transporter to import glucose against its concentration gradient. What is the source of energy for this process?

Accepted Answer

The downhill movement of sodium ions established by the sodium-potassium pump.

Question 7

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

Accepted Answer

Providing structural support to the cell wall

Question 8

Dr. Cynthia Lucero collapsed during a marathon after drinking excessive Gatorade, which is less salty than blood. What physiological process most likely contributed to her condition?

Accepted Answer

Osmosis caused water to move into her cells, leading to swelling

Question 9

Which of the following statements about passive transport is TRUE?

Accepted Answer

It can occur via simple diffusion or facilitated diffusion.

Question 10

Which process is responsible for the secretion of insulin from pancreatic cells?

Accepted Answer

Exocytosis

Question 11

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

Accepted Answer

It will remain the same size because water movement is balanced.

Question 12

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

Accepted Answer

It has a hydrophilic head and two hydrophobic tails.

Question 13

Which type of membrane transport requires energy and moves substances against their concentration gradient?

Accepted Answer

Active transport

Question 14

Which of the following is an example of bulk transport?

Accepted Answer

Endocytosis of bacteria by immune cells

Question 15

If a cell lacks aquaporin channels, what would be the most likely consequence?

Accepted Answer

Water would not be able to enter or leave the cell efficiently.

Question 16

Which of the following best describes the movement of sodium ions by the sodium-potassium pump?

Accepted Answer

Sodium ions move out of the cell against their concentration gradient using ATP.

Question 17

Which of the following statements about membrane permeability is correct?

Accepted Answer

Small, uncharged, hydrophobic molecules cross the membrane easily.

Question 18

Which equation best represents the direction of water movement during osmosis?

Accepted Answer

$$	ext{Water moves from low solute concentration to high solute concentration}$$

Question 19

Which of the following is TRUE about cotransport?

Accepted Answer

It couples the movement of one substance down its gradient to the movement of another against its gradient.

Membrane Transport: How Substances Cross Cellular Membranes

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