Q: A cell uses the sodium-potassium pump to maintain ion gradients. Which equation best represents the energy requirement for this process?

$\text{ATP} \rightarrow \text{ADP} + \text{P}_i$

Question 1

Which of the following best describes the primary function of the plasma membrane in regulating cellular traffic?

Accepted Answer

It selectively regulates the movement of substances in and out of the cell, maintaining homeostasis.

Question 2

Which process requires energy input from the cell to move solutes against their concentration gradient?

Accepted Answer

Active transport

Question 3

A neuron must quickly release neurotransmitters into the synaptic cleft. Which membrane process is responsible for this?

Accepted Answer

Exocytosis

Question 4

Which of the following equations correctly represents the net movement of molecules during simple diffusion?

Accepted Answer

$J = -D \frac{dC}{dx}$

Question 5

A cell is placed in a solution with a higher concentration of solutes than inside the cell. What will most likely happen to the cell?

Accepted Answer

Water will move out of the cell, causing it to shrink.

Question 6

Which of the following best explains why the plasma membrane is described as a 'fluid mosaic'?

Accepted Answer

It consists of phospholipids and proteins that can move laterally within the layer.

Question 7

Which type of transport is illustrated by the movement of glucose into a cell via a specific carrier protein, without energy expenditure?

Accepted Answer

Facilitated diffusion

Question 8

During endocytosis, which of the following occurs?

Accepted Answer

The plasma membrane folds inward to engulf extracellular material.

Question 9

Which of the following statements about passive transport is correct?

Accepted Answer

It relies on the natural kinetic energy of molecules to move substances down their concentration gradient.

Question 10

A cell uses the sodium-potassium pump to maintain ion gradients. Which equation best represents the energy requirement for this process?

Accepted Answer

$	ext{ATP} ightarrow 	ext{ADP} + 	ext{P}_i$

Question 11

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

Accepted Answer

Providing structural support to the cell wall

Question 12

A patient is given intravenous fluids that are hypotonic compared to their blood plasma. What is the most likely effect on their red blood cells?

Accepted Answer

Red blood cells will burst due to water influx.

Question 13

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

Accepted Answer

It stabilizes membrane fluidity by preventing extremes in flexibility and rigidity.

Question 14

Which process is most directly responsible for the uptake of large particles, such as bacteria, by immune cells?

Accepted Answer

Phagocytosis

Question 15

If a cell's membrane becomes less permeable to oxygen, what is the most likely consequence?

Accepted Answer

Cellular respiration will decrease due to reduced oxygen availability.

Question 16

Which of the following is a correct statement about the movement of water across the plasma membrane?

Accepted Answer

Water moves through aquaporins by facilitated diffusion.

Question 17

A cell is actively transporting ions out of its cytoplasm. Which of the following is true about this process?

Accepted Answer

It requires energy, often in the form of ATP.

Question 18

Which of the following best explains why facilitated diffusion is necessary for glucose transport into most cells?

Accepted Answer

Glucose is a large, polar molecule that requires a carrier protein to cross the membrane.

Question 19

Which equation best represents the relationship between membrane permeability ($P$), surface area ($A$), concentration difference ($\Delta C$), and rate of diffusion ($R$)?

Accepted Answer

$R = P 	imes A 	imes \Delta C$

Membrane Structure and Function: Regulation of Cellular Transport

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