Q: Which equation correctly represents the movement of sodium and potassium ions by the sodium-potassium pump?

$3 \mathrm{Na}^+_{\text{in}} + 2 \mathrm{K}^+_{\text{out}} + \mathrm{ATP} \rightarrow 3 \mathrm{Na}^+_{\text{out}} + 2 \mathrm{K}^+_{\text{in}} + \mathrm{ADP} + \mathrm{P}_i$

Question 1

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

Accepted Answer

The membrane consists of a dynamic bilayer of phospholipids with embedded proteins that can move laterally.

Question 2

Phospholipids are described as amphipathic. What does this mean?

Accepted Answer

They have both hydrophilic and hydrophobic regions.

Question 3

Which of the following changes would most likely increase membrane fluidity?

Accepted Answer

Increasing the proportion of unsaturated fatty acid tails in phospholipids.

Question 4

Which function is NOT typically associated with membrane proteins?

Accepted Answer

Synthesis of DNA.

Question 5

Which of the following best distinguishes between channel proteins and carrier proteins?

Accepted Answer

Channel proteins form hydrophilic tunnels for passive movement; carrier proteins bind and change shape to move molecules across.

Question 6

Which of the following molecules would most likely cross the plasma membrane by simple diffusion?

Accepted Answer

O\_2

Question 7

A red blood cell placed in a hypotonic solution will:

Accepted Answer

Burst as water enters the cell.

Question 8

Which equation correctly represents the movement of sodium and potassium ions by the sodium-potassium pump?

Accepted Answer

$3 \mathrm{Na}^+_{	ext{in}} + 2 \mathrm{K}^+_{	ext{out}} + \mathrm{ATP} ightarrow 3 \mathrm{Na}^+_{	ext{out}} + 2 \mathrm{K}^+_{	ext{in}} + \mathrm{ADP} + \mathrm{P}_i$

Question 9

Facilitated diffusion differs from simple diffusion in that:

Accepted Answer

Facilitated diffusion requires a transport protein to move molecules down their concentration gradient.

Question 10

Which of the following is an example of bulk transport across the plasma membrane?

Accepted Answer

Exocytosis

Question 11

Which statement best explains why plant cells do not burst in hypotonic solutions?

Accepted Answer

Plant cells have a rigid cell wall that prevents bursting.

Question 12

Which of the following best describes receptor-mediated endocytosis?

Accepted Answer

The cell takes in specific molecules after they bind to receptors on the membrane.

Question 13

Which of the following is true about aquaporins?

Accepted Answer

They are channel proteins that facilitate rapid water movement across membranes.

Question 14

Which of the following best describes the role of cholesterol in the plasma membrane?

Accepted Answer

Cholesterol increases membrane fluidity at high temperatures and decreases it at low temperatures.

Question 15

Which process is responsible for the movement of water across a selectively permeable membrane?

Accepted Answer

Osmosis

Question 16

Which of the following best describes the difference between glycolipids and glycoproteins?

Accepted Answer

Glycolipids are lipids with attached carbohydrate chains; glycoproteins are proteins with attached carbohydrate chains.

Question 17

Which of the following is NOT a form of passive transport?

Accepted Answer

Endocytosis

Question 18

A cell is placed in a solution and water moves out of the cell, causing it to shrink. What type of solution is this?

Accepted Answer

Hypertonic

Question 19

Which of the following best describes active transport?

Accepted Answer

Movement of molecules against their concentration gradient using energy from ATP.

Question 20

Which of the following is a correct example of facilitated diffusion?

Accepted Answer

Glucose entering a cell via a carrier protein.

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