Question 1

Which of the following best explains why oxygen ($$O_2) $$can easily diffuse across the plasma membrane, while glucose cannot?

Accepted Answer

Oxygen is a small, non-polar molecule, while glucose is large and polar.

Question 2

A red blood cell is placed in a solution and begins to swell until it bursts. Which of the following best describes the tonicity of the solution relative to the cell?

Accepted Answer

The solution is hypotonic compared to the cell.

Question 3

Which of the following statements about the fluid mosaic model of the plasma membrane is CORRECT?

Accepted Answer

Membrane proteins can move laterally within the lipid bilayer.

Question 4

Which process requires the direct use of ATP to move substances against their concentration gradient?

Accepted Answer

Primary active transport

Question 5

A cell is placed in a hypertonic solution. What will most likely happen to the cell?

Accepted Answer

Water will leave the cell, causing it to shrink (crenate).

Question 6

Which of the following best describes secondary active transport?

Accepted Answer

It uses the energy stored in a concentration gradient established by primary active transport.

Question 7

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

Accepted Answer

Synthesis of DNA

Question 8

A white blood cell engulfs a bacterium by extending pseudopods around it. What is this process called?

Accepted Answer

Phagocytosis

Question 9

Which of the following factors would NOT increase the rate of diffusion across a cell membrane?

Accepted Answer

Increasing the mass of the diffusing substance

Question 10

A cell uses receptor-mediated endocytosis to import cholesterol. Which of the following best describes this process?

Accepted Answer

Specific molecules bind to receptors, triggering vesicle formation.

Question 11

Which of the following best explains why ions such as $$Na^+$$ and $$K^+$$ cannot cross the plasma membrane by simple diffusion?

Accepted Answer

They are charged and cannot pass through the hydrophobic core of the membrane.

Question 12

Which of the following scenarios illustrates facilitated diffusion?

Accepted Answer

Glucose moves into a cell through a transporter protein, down its concentration gradient.

Question 13

A cell is placed in an iso-osmotic solution. What will happen to the cell?

Accepted Answer

There will be no net movement of water into or out of the cell.

Question 14

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

Accepted Answer

It stabilizes the membrane, making it less likely to break apart at warm temperatures.

Question 15

Which of the following is an example of bulk transport?

Accepted Answer

Exocytosis of neurotransmitters from a neuron

Question 16

Which of the following statements about osmosis is CORRECT?

Accepted Answer

Water moves from an area of higher water concentration to an area of lower water concentration across a selectively permeable membrane.

Question 17

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

Accepted Answer

They help the immune system distinguish self from non-self.

Question 18

A patient is given an intravenous (IV) solution that is hypertonic to their red blood cells. What is the most likely outcome for the red blood cells?

Accepted Answer

They will lose water and shrink.

Question 19

Which of the following is TRUE about the movement of substances by simple diffusion?

Accepted Answer

It does not require cellular energy and moves substances down their concentration gradient.

Question 20

Which of the following best explains why facilitated diffusion exhibits a transport maximum?

Accepted Answer

All available transport proteins can become saturated, limiting the rate of diffusion.

Cell Membrane Structure and Transport Mechanisms

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