$$3 \text{Na}^+_{\text{out}} : 2 \text{K}^+_{\text{in}}$$

Question 1

Which scientist is credited with first observing cells and coining the term 'cell'?

Accepted Answer

Robert Hooke

Question 2

According to the modern cell theory, which statement is TRUE?

Accepted Answer

Cells contain hereditary information (DNA) that is passed during cell division.

Question 3

Which of the following best explains why most human cells are limited to a diameter of 10-15 μm?

Accepted Answer

As cell size increases, the surface-to-volume ratio decreases, limiting efficient exchange of materials.

Question 4

Which of the following is NOT a basic component of all cells?

Accepted Answer

Cell wall

Question 5

In the fluid mosaic model of the plasma membrane, which molecule forms the basic structural framework?

Accepted Answer

Phospholipids

Question 6

Which membrane component is primarily responsible for cell recognition and communication?

Accepted Answer

Carbohydrates attached to proteins and lipids

Question 7

A patient receives a hypertonic IV solution. What is the most likely effect on their red blood cells?

Accepted Answer

Cells will shrink as water moves out by osmosis.

Question 8

Which of the following best describes facilitated diffusion?

Accepted Answer

Movement of solutes down their concentration gradient via membrane proteins, without energy input.

Question 9

Which equation correctly represents the relationship between surface area and volume for a spherical cell?

Accepted Answer

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

Question 10

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

Accepted Answer

Decreasing membrane permeability

Question 11

A cell uses the sodium-potassium pump to maintain its membrane potential. Which equation best represents the pump's activity?

Accepted Answer

$$3 	ext{Na}^+_{	ext{out}} : 2 	ext{K}^+_{	ext{in}}$$

Question 12

Which type of membrane transport requires energy and moves substances against their concentration gradient?

Accepted Answer

Active transport

Question 13

A glucose symporter in the intestinal epithelium uses the sodium gradient to transport glucose into the cell. This is an example of:

Accepted Answer

Secondary active transport

Question 14

Which process involves the movement of large particles into the cell by engulfing them in membrane-derived vesicles?

Accepted Answer

Phagocytosis

Question 15

During vigorous exercise, athletes lose water and electrolytes through sweating. Why are sports drinks often hypotonic?

Accepted Answer

To replenish lost water and electrolytes, allowing water to move back into cells and restore normal cytosol concentration.

Question 16

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

Accepted Answer

They allow water to diffuse rapidly across the membrane.

Question 17

Which of the following is an example of receptor-mediated endocytosis?

Accepted Answer

Uptake of low-density lipoprotein (LDL) from the bloodstream

Question 18

Which of the following statements about membrane potential is CORRECT?

Accepted Answer

Membrane potential is measured in millivolts and is negative at rest.

Question 19

Which type of membrane protein transports two or more substances in opposite directions across the membrane?

Accepted Answer

Antiport

Question 20

A cell is placed in a solution with a lower solute concentration than its cytosol. What will happen to the cell?

Accepted Answer

Water will move into the cell, causing it to swell.

Cell Membrane: Structure, Function, and Transport Mechanisms (Chapter 3 Study Notes)

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