Question 1

Which of the following statements best describes the difference between simple diffusion and facilitated diffusion across a cell membrane?

Accepted Answer

Facilitated diffusion uses transport proteins to move solutes, while simple diffusion does not.

Question 2

A red blood cell is placed in a solution with a higher solute concentration than its cytoplasm. What will happen to the cell, and which process is responsible?

Accepted Answer

The cell will shrink due to osmosis.

Question 3

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

Accepted Answer

Oxygen ($$\mathrm{O}_2)$$

Question 4

Carrier proteins that transport a single solute across the membrane are called:

Accepted Answer

Uniporters

Question 5

Which of the following best describes indirect active transport?

Accepted Answer

It couples the movement of one solute down its gradient to drive the movement of another solute up its gradient.

Question 6

A patient receives an intravenous solution that is hypotonic relative to their blood plasma. What is the most likely outcome for their red blood cells?

Accepted Answer

The cells will swell as water enters the cell.

Question 7

Which equation best represents the hydrolysis of ATP used in direct active transport?

Accepted Answer

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

Question 8

Which of the following is NOT a characteristic of channel proteins?

Accepted Answer

They bind solutes and undergo conformational changes.

Question 9

In the sodium-potassium pump, which ions are moved and in which direction?

Accepted Answer

$$3\ \mathrm{Na}^+$$ out, $$2\ \mathrm{K}^+ in$$

Question 10

Which of the following scenarios best illustrates symport?

Accepted Answer

A protein moves two solutes in the same direction across the membrane.

Question 11

What is the main driving force for osmosis across a cell membrane?

Accepted Answer

The movement of water from high to low concentration.

Question 12

Which of the following is true about facilitated diffusion?

Accepted Answer

It moves solutes down their concentration gradient.

Question 13

A cell is placed in a very hypotonic solution. What is the most likely outcome?

Accepted Answer

The cell will lyse (burst).

Question 14

Which of the following best describes antiport transport?

Accepted Answer

Two solutes are moved in opposite directions across the membrane.

Question 15

Which of the following is an example of direct active transport?

Accepted Answer

Sodium-potassium pump using ATP hydrolysis

Question 16

Which of the following is NOT a feature of osmosis?

Accepted Answer

It requires energy input from ATP.

Question 17

A cell maintains its size in an isotonic environment primarily by:

Accepted Answer

Balancing solute concentrations inside and outside the cell.

Question 18

Which of the following best describes the function of carrier proteins in facilitated diffusion?

Accepted Answer

They bind solutes, undergo conformational changes, and release solutes on the other side.

Question 19

Which of the following is a plausible consequence of a malfunctioning sodium-potassium pump in human cells?

Accepted Answer

Cells would be unable to maintain their membrane potential.

Question 20

Which of the following best explains why steroid hormones can cross the plasma membrane by simple diffusion?

Accepted Answer

They are hydrophobic and can dissolve in the lipid bilayer.

Transport Across Membranes: Overcoming the Permeability Barrier

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