Question 1

Which of the following best explains why micelles form spontaneously in water?

Accepted Answer

Micelles form because hydrophobic groups are sequestered from water, minimizing the ordered shell of water molecules and increasing entropy.

Question 2

What happens to a cell placed in a hypertonic solution, and why?

Accepted Answer

Water moves out of the cell, causing it to shrink because the extracellular solute concentration is higher.

Question 3

Which of the following statements about entropy during micelle formation is correct?

Accepted Answer

Entropy increases because fewer water molecules are ordered around hydrophobic groups.

Question 4

A red blood cell is placed in a hypotonic solution. Predict and explain the outcome.

Accepted Answer

Water moves into the cell, causing it to swell and possibly burst due to lower extracellular solute concentration.

Question 5

Which equation best describes the osmotic pressure ($$\Pi) $$across a semipermeable membrane?

Accepted Answer

$$\Pi = iMRT$$

Question 6

Why do clusters of lipid molecules at the edge of a cluster force the ordering of water?

Accepted Answer

Because only lipid portions at the edge interact with water, causing water molecules to become more ordered and decreasing entropy.

Question 7

A patient receives an intravenous solution that is hypotonic relative to their blood plasma. What is the most likely cellular response?

Accepted Answer

Red blood cells will swell and may burst due to water influx.

Question 8

Which of the following best describes the arrangement of lipid molecules in a micelle?

Accepted Answer

Hydrophobic tails are sequestered inside, and hydrophilic heads face outward toward water.

Question 9

If a cell is placed in an isotonic solution, what will happen to the cell volume?

Accepted Answer

The cell volume will remain unchanged due to no net water movement.

Question 10

Which of the following scenarios best illustrates the principle of osmosis?

Accepted Answer

A cell placed in pure water swells as water enters the cell.

Question 11

Which of the following is a direct consequence of the hydrophobic effect in biological systems?

Accepted Answer

Formation of micelles from amphipathic molecules in water.

Question 12

A solution contains 0.2 M NaCl and a cell is placed in this solution. If the cell's cytoplasm is 0.15 M NaCl, what will happen?

Accepted Answer

Water will move out of the cell, causing it to shrink.

Question 13

Which of the following best describes the entropy change when micelles form from individual lipid molecules in water?

Accepted Answer

Entropy increases because fewer water molecules are ordered around hydrophobic groups.

Question 14

Which of the following is NOT a characteristic of a micelle?

Accepted Answer

Hydrophobic tails are exposed to water.

Question 15

A cell is placed in a solution and water moves into the cell, causing it to burst. What type of solution is this?

Accepted Answer

Hypotonic

Membrane Structure, Micelle Formation, and Osmosis

Study Guide - Practice Questions