Q: Which of the following equations correctly represents the relationship between solute concentration and water movement across a semipermeable membrane?

$ \text{Osmosis} = \text{movement of water from low solute concentration to high solute concentration} $

Question 1

Which of the following best describes the structure of a phospholipid molecule in the plasma membrane?

Accepted Answer

A hydrophilic head and two hydrophobic tails

Question 2

A red blood cell is placed in a hypertonic solution. What will most likely happen to the cell, and why?

Accepted Answer

It will shrink because water leaves the cell by osmosis.

Question 3

Which of the following is a function of integral membrane proteins in the plasma membrane?

Accepted Answer

They serve as channels or transporters for molecules across the membrane.

Question 4

Which component of the plasma membrane is primarily responsible for its fluidity at body temperature?

Accepted Answer

Cholesterol

Question 5

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

Accepted Answer

The cells will swell and may burst due to water gain.

Question 6

Which of the following best explains why the plasma membrane is described as a 'semipermeable' membrane?

Accepted Answer

It allows some substances to pass while restricting others.

Question 7

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

Accepted Answer

They are involved in cell recognition and signaling.

Question 8

A scientist is studying the movement of oxygen across the plasma membrane. Which process is primarily responsible for this movement?

Accepted Answer

Simple diffusion

Question 9

Which of the following equations correctly represents the relationship between solute concentration and water movement across a semipermeable membrane?

Accepted Answer

$ 	ext{Osmosis} = 	ext{movement of water from low solute concentration to high solute concentration} $

Question 10

Which of the following best describes the difference between saturated and unsaturated fatty acids in the phospholipid bilayer?

Accepted Answer

Unsaturated fatty acids have kinks due to double bonds, increasing membrane fluidity.

Question 11

A cell is placed in an isotonic solution. What will happen to the cell's volume over time?

Accepted Answer

It will remain the same as water moves in and out at equal rates.

Question 12

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

Accepted Answer

Synthesizing proteins for export

Question 13

Which of the following best explains why ions such as Na$^+$ and K$^+$ require channel proteins to cross the plasma membrane?

Accepted Answer

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

Question 14

Which of the following best describes the arrangement of phospholipids in the plasma membrane?

Accepted Answer

Hydrophilic heads face the extracellular and intracellular fluids, tails face inward.

Question 15

A mutation causes a cell to lack cholesterol in its plasma membrane. Which of the following is a likely consequence?

Accepted Answer

The membrane will become too fluid and less stable.

Question 16

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

Accepted Answer

They allow specific molecules or ions to pass through the membrane.

Question 17

Which of the following is a real-world example of facilitated diffusion across the plasma membrane?

Accepted Answer

Glucose entering a muscle cell via a GLUT transporter

Question 18

Which of the following statements about the plasma membrane is correct?

Accepted Answer

It contains both lipids and proteins that contribute to its function.

Question 19

Which of the following best explains why the plasma membrane is described as a 'fluid mosaic'?

Accepted Answer

It is made of many different molecules that can move laterally within the layer.

Question 20

A cell is exposed to a toxin that blocks all channel proteins in its plasma membrane. Which of the following processes would be most directly affected?

Accepted Answer

Facilitated diffusion of ions

Cellular Level of Organization: The Cell Membrane

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