Question 1

Which statement best describes the fluid-mosaic model of biological membranes?

Accepted Answer

Membranes consist of a fluid phospholipid bilayer with proteins embedded or attached, allowing lateral movement of components.

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 term describes the solution?

Accepted Answer

The cell will shrink; the solution is hypertonic.

Question 3

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

Accepted Answer

Oxygen ($$O_2)$$

Question 4

What is the primary function of the sodium-potassium pump in animal cells?

Accepted Answer

To actively transport $$Na^+$$ out of the cell and $$K^+$$ into the cell, maintaining electrochemical gradients.

Question 5

Which equation correctly represents osmotic pressure ($$	ext{OP}) $$according to van't Hoff's law?

Accepted Answer

$$	ext{OP} = iMRT$$

Question 6

A plant cell is placed in pure water. What will happen to the cell, and why?

Accepted Answer

It will become turgid because water enters the cell due to the hypotonic environment.

Question 7

Which of the following best explains why cholesterol is important for membrane fluidity?

Accepted Answer

Cholesterol maintains membrane fluidity by preventing tight packing at low temperatures and restraining movement at high temperatures.

Question 8

Which type of membrane transport requires energy input from the cell?

Accepted Answer

Active transport

Question 9

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

Accepted Answer

Red blood cells will burst (lyse) due to water influx.

Question 10

Which of the following is NOT a component of the endomembrane system?

Accepted Answer

Mitochondria

Question 11

Which process describes the movement of water across a selectively permeable membrane from an area of low solute concentration to high solute concentration?

Accepted Answer

Osmosis

Question 12

Which of the following best describes facilitated diffusion?

Accepted Answer

Movement of molecules down their concentration gradient through a membrane protein without energy input.

Question 13

A cell uses a proton pump to create a gradient of $$H^+$$ ions. How can this gradient be used to import sucrose into the cell?

Accepted Answer

The $$H^+$$ gradient drives the co-transport of sucrose via a symporter protein.

Question 14

Which of the following is a real-life example of bulk transport in cells?

Accepted Answer

White blood cells engulfing bacteria by phagocytosis

Question 15

Which equation best represents the relationship between surface area ($$SA) $$and volume ($$V) $$for a spherical cell?

Accepted Answer

$$SA = 4\pi r^2$, V$$ = \frac{4}{3}\pi $$r^3$$

Question 16

Which of the following statements about membrane proteins is correct?

Accepted Answer

Membrane proteins can function as transporters, receptors, or enzymes.

Question 17

A corn farmer applies extra fertilizer, creating a hypertonic environment around the roots. What is the most likely effect on the crop?

Accepted Answer

The plants will wilt due to water loss from root cells.

Question 18

Which of the following best describes the role of aquaporins in the cell membrane?

Accepted Answer

Aquaporins facilitate the passive movement of water across the membrane.

Question 19

Which of the following is true about the movement of ions across a membrane in the presence of an electrochemical gradient?

Accepted Answer

Ions move in a direction determined by both their concentration gradient and the membrane potential.

Membrane Structure and Transport: Study Guide for General Biology

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