Q: Which equation best represents the movement of sodium and potassium ions by the Na/K pump?

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

Question 1

Which of the following statements best explains why unsaturated fats are liquid at room temperature?

Accepted Answer

Unsaturated fats have double bonds that create kinks, preventing tight packing of molecules.

Question 2

Which type of lipid is a major component of the plasma membrane and contributes to its fluidity and permeability?

Accepted Answer

Phospholipids

Question 3

A patient has a diet high in saturated fats. Which of the following is most likely to occur in their plasma membranes?

Accepted Answer

Decreased fluidity due to tightly packed fatty acid chains

Question 4

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

Accepted Answer

Cholesterol stabilizes the membrane by decreasing fluidity.

Question 5

Which equation best represents the movement of sodium and potassium ions by the Na/K pump?

Accepted Answer

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

Question 6

Which process allows water to move across a plasma membrane from an area of low solute concentration to high solute concentration?

Accepted Answer

Osmosis

Question 7

A cell is placed in a solution with a higher concentration of glucose than inside the cell. Which transport mechanism will glucose most likely use to enter the cell?

Accepted Answer

Facilitated diffusion through carrier proteins

Question 8

Which of the following molecules can most easily cross the plasma membrane by simple diffusion?

Accepted Answer

O$_2$

Question 9

Which of the following is TRUE about passive transport?

Accepted Answer

It moves substances down their concentration gradient without using ATP.

Question 10

Which process is responsible for the uptake of large molecules such as proteins into a cell?

Accepted Answer

Endocytosis

Question 11

A cell uses ATP to move Na$^+$ ions out and K$^+$ ions in. What type of transport is this?

Accepted Answer

Active transport

Question 12

Which of the following best describes the function of channel proteins in the plasma membrane?

Accepted Answer

They allow specific ions or molecules to pass through the membrane down their concentration gradient.

Question 13

Which process involves the fusion of vesicles with the plasma membrane to release their contents outside the cell?

Accepted Answer

Exocytosis

Question 14

Which of the following is a key difference between carrier proteins and channel proteins?

Accepted Answer

Carrier proteins undergo conformational changes to transport molecules, while channel proteins form open pores.

Question 15

Which of the following best describes receptor-mediated endocytosis?

Accepted Answer

It is a selective process where specific molecules bind to receptors before being internalized.

Question 16

Which of the following would most likely increase the permeability of a plasma membrane?

Accepted Answer

Increasing the proportion of unsaturated fatty acids in phospholipids

Question 17

Which of the following is TRUE about the movement of charged molecules across the plasma membrane?

Accepted Answer

Charged molecules require transport proteins to cross the membrane.

Question 18

Which process is most likely to be used by a cell to take in extracellular fluid and dissolved solutes?

Accepted Answer

Pinocytosis

Question 19

A cell is exposed to a toxin that blocks ATP production. Which transport process will be most directly affected?

Accepted Answer

Active transport

Question 20

Which of the following best explains why phospholipids form bilayers in water?

Accepted Answer

Their hydrophilic heads interact with water while hydrophobic tails avoid water.

Membrane Structure, Lipids, and Transport Mechanisms

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