Question 1

Which of the following best describes the structure of a biological membrane according to the fluid mosaic model?

Accepted Answer

A phospholipid bilayer with proteins and cholesterol moving laterally within it.

Question 2

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

Accepted Answer

Synthesizing proteins.

Question 3

A molecule moves down its concentration gradient when it travels from:

Accepted Answer

An area of high concentration to an area of low concentration.

Question 4

Which molecule most easily diffuses across a biological membrane’s lipid bilayer, without the help of a protein?

Accepted Answer

O2

Question 5

Which process is also called 'cell eating' and is a type of large molecule transport?

Accepted Answer

Phagocytosis

Question 6

Passive membrane transport processes include:

Accepted Answer

Movement of a substance down its concentration gradient.

Question 7

A transport protein that simultaneously transports two different molecules in different directions is called:

Accepted Answer

An antiporter.

Question 8

Osmosis is best defined as the movement of:

Accepted Answer

Water molecules across a semi-permeable membrane into a region of high solute concentration.

Question 9

A red blood cell is placed in a solution containing 10% solute, while the cell’s cytoplasm contains 0.1% solute. What will happen to the cell?

Accepted Answer

The cell will shrivel.

Question 10

Plants become turgid when placed in which type of solution?

Accepted Answer

Hypotonic

Question 11

Which of the following processes includes all of the others?

Accepted Answer

Passive transport.

Question 12

Which type(s) of molecules cannot enter/exit the cell via simple diffusion and require facilitated diffusion?

Accepted Answer

Charged Ca2+ ions and charged Na+ ions.

Question 13

The force driving simple diffusion is $$	ext{a concentration gradient}$$, while the energy source for active transport is:

Accepted Answer

$$	ext{ATP hydrolysis}$$

Question 14

A sodium-potassium pump:

Accepted Answer

Transports 3 sodium ions out of a cell and 2 potassium ions into a cell using energy from ATP hydrolysis.

Question 15

How are primary and secondary active transport related?

Accepted Answer

Secondary active transport uses the concentration gradient established by primary active transport.

Question 16

Which of the following is NOT a true statement regarding exocytosis?

Accepted Answer

It forms intracellular vesicles from inward folding of the plasma membrane.

Question 17

Which of the following best describes a transporter that requires ATP to move molecules A and B out of the cell?

Accepted Answer

An active antiporter.

Question 18

Which of the following best explains why charged ions such as Na+ cannot freely diffuse across the lipid bilayer?

Accepted Answer

They are repelled by the hydrophobic interior of the membrane.

Question 19

Which of the following is a correct statement about facilitated diffusion?

Accepted Answer

It requires a protein transporter.

Question 20

Which of the following best describes the difference between simple and facilitated diffusion?

Accepted Answer

Facilitated diffusion requires a protein transporter, while simple diffusion does not.

Biological Membranes and Membrane Transport: Structure, Function, and Mechanisms

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