Question 1

Which of the following best describes the fluid mosaic model of the plasma membrane?

Accepted Answer

A double layer of phospholipids with proteins and cholesterol embedded, allowing lateral movement of components.

Question 2

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

Accepted Answer

Synthesis of DNA.

Question 3

A protein that spans the entire membrane and is involved in transporting ions is best classified as:

Accepted Answer

An integral membrane protein.

Question 4

Which of the following statements about transmembrane domains is correct?

Accepted Answer

They anchor proteins within the lipid bilayer by spanning the membrane.

Question 5

Facilitated diffusion differs from simple diffusion in that facilitated diffusion:

Accepted Answer

Utilizes membrane proteins to transport substances down their concentration gradient.

Question 6

Which of the following best describes the difference between channel proteins and carrier proteins?

Accepted Answer

Channel proteins form hydrophilic pores for passive movement, while carrier proteins undergo conformational changes to move molecules.

Question 7

Which scenario is an example of active transport?

Accepted Answer

Sodium ions being pumped out of a neuron against their concentration gradient using ATP.

Question 8

The Na$$^+/K$^+$$ pump moves ions across the plasma membrane. Which of the following correctly describes its function?

Accepted Answer

It moves 3 Na$$^+$$ ions out of the cell and 2 K$$^+$$ ions in, using ATP.

Question 9

Which of the following best defines tonicity?

Accepted Answer

The ability of a surrounding solution to cause a cell to gain or lose water.

Question 10

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

Accepted Answer

It will swell and possibly burst as water enters the cell.

Question 11

Which process is responsible for the uptake of large particles, such as bacteria, by a white blood cell?

Accepted Answer

Phagocytosis

Question 12

Which of the following best describes the electrochemical gradient?

Accepted Answer

The combined effect of a chemical concentration gradient and an electrical gradient across a membrane.

Question 13

Which of the following is a correct sequence for the three stages of cell signaling?

Accepted Answer

Reception, transduction, response

Question 14

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

Accepted Answer

The cell will undergo plasmolysis as water leaves.

Question 15

Which of the following best explains why the movement of glucose into a cell via the sodium-glucose cotransporter is considered secondary active transport?

Accepted Answer

It relies on the sodium gradient established by the Na$$^+/K$^+$$ pump, which uses ATP.

Question 16

Which of the following would most likely increase membrane fluidity?

Accepted Answer

Increasing the proportion of unsaturated fatty acids in phospholipids.

Question 17

Which of the following is true regarding movement 'against the gradient'?

Accepted Answer

It requires energy input, such as ATP hydrolysis.

Question 18

Which of the following best describes exocytosis?

Accepted Answer

The process by which cells expel materials in vesicles that fuse with the plasma membrane.

Question 19

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

Accepted Answer

It will remain the same as water moves in and out at equal rates.

Question 20

Which of the following is a real-life example of receptor-mediated endocytosis?

Accepted Answer

Uptake of cholesterol via LDL receptors in human cells.

CH 5 end slide

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