Q: Which equation correctly represents the relationship between the rate of diffusion ($$R$$), concentration gradient ($$ riangle C$$), membrane permeability ($$P$$), and surface area ($$A$$)?

$$R = P \times A \times \triangle C$$

Question 1

Which of the following best describes the function of the plasma membrane in a human cell?

Accepted Answer

It acts as a flexible barrier that controls what enters and leaves the cell.

Question 2

A red blood cell is placed in a hypertonic solution. What is the expected outcome, and which term describes this process?

Accepted Answer

Water leaves the cell, causing it to shrink; this is called crenation.

Question 3

Which of the following molecules can passively diffuse through the plasma membrane without assistance?

Accepted Answer

Oxygen

Question 4

What is the primary difference between simple diffusion and facilitated diffusion across the plasma membrane?

Accepted Answer

Simple diffusion involves nonpolar molecules passing directly through the lipid bilayer, while facilitated diffusion requires carrier or channel proteins for polar molecules.

Question 5

Which equation correctly represents the relationship between the rate of diffusion ($$R$$), concentration gradient ($$	riangle C$$), membrane permeability ($$P$$), and surface area ($$A$$)?

Accepted Answer

$$R = P 	imes A 	imes 	riangle C$$

Question 6

A patient with severe burns is losing fluids and proteins from damaged cells. Which property of the plasma membrane has been compromised?

Accepted Answer

Its selective permeability.

Question 7

Which of the following best explains why water can move through the plasma membrane despite being polar?

Accepted Answer

Water is small enough to pass through the lipid bilayer and also moves through aquaporins.

Question 8

Which process requires energy (ATP) to move solutes across the plasma membrane?

Accepted Answer

Active transport

Question 9

A cell is actively engulfing bacteria using extensions of its plasma membrane. Which process is occurring?

Accepted Answer

Phagocytosis

Question 10

Which of the following is a function of the glycocalyx on the cell surface?

Accepted Answer

It serves as a biological marker for cell-to-cell recognition.

Question 11

Which of the following best describes receptor-mediated endocytosis?

Accepted Answer

The cell uses specific receptors to internalize particular molecules along with the vesicle.

Question 12

Which of the following is NOT a major region of a generalized human cell?

Accepted Answer

Mitochondria

Question 13

Which type of membrane protein is most likely to be involved in cell signaling and communication?

Accepted Answer

Integral proteins

Question 14

A cell placed in a hypotonic solution will:

Accepted Answer

Gain water and swell, possibly bursting (lysing).

Question 15

Which of the following best describes the fluid mosaic model of the plasma membrane?

Accepted Answer

A flexible bilayer of lipids with proteins floating and moving within it.

Question 16

Which equation best represents the osmotic pressure ($$\Pi) $$generated by a solution, where $$C is $$the molar concentration, $$R is $$the gas constant, and $$T is $$the temperature in Kelvin?

Accepted Answer

$$\Pi = C 	imes R 	imes T$$

Question 17

Which of the following is an example of vesicular transport that moves substances out of the cell?

Accepted Answer

Exocytosis

Question 18

Which of the following statements about the continuity of life is correct?

Accepted Answer

Cells can arise only from other preexisting cells.

Question 19

Which of the following is a real-life example of receptor-mediated endocytosis?

Accepted Answer

Cells taking in low-density lipoproteins (LDL) from the bloodstream.

Question 20

Which of the following best explains why cholesterol is important in the plasma membrane?

Accepted Answer

It increases membrane stability and fluidity.

Cells: The Living Units – Structure, Diversity, and Membrane Transport

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