Question 1

Which of the following molecules would most easily pass through a cell's phospholipid bilayer without the aid of a transport protein?

Accepted Answer

A small hydrophobic molecule such as oxygen ($$O_2)$$

Question 2

A scientist is studying the effect of temperature on membrane permeability. If the temperature is increased, what is the most likely effect on the movement of molecules across the membrane?

Accepted Answer

Membrane permeability will increase due to greater molecular movement.

Question 3

Which of the following best describes the role of cholesterol in animal cell membranes at normal physiological temperatures ($$37^\circ C$$)?

Accepted Answer

It stabilizes membrane fluidity by limiting movement of phospholipid fatty acid tails.

Question 4

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

Accepted Answer

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

Question 5

Which of the following factors would most likely increase the fluidity of a cell membrane?

Accepted Answer

Increasing the proportion of unsaturated fatty acid tails in phospholipids

Question 6

Which statement about passive transport across a cell membrane is correct?

Accepted Answer

Molecules move down their concentration gradient without energy investment.

Question 7

A plant cell is placed in a hypotonic solution. What is the expected outcome?

Accepted Answer

The cell will become turgid.

Question 8

Which of the following is a characteristic feature of a carrier protein in a plasma membrane?

Accepted Answer

It is specific for a particular type of molecule.

Question 9

A cell surrounded by a semi-permeable membrane contains a $$0.1\,M$$ solution of glucose and is placed in a beaker containing a $$0.5\,M$$ solution of sucrose. The membrane is permeable to water but not to glucose or sucrose. What will happen?

Accepted Answer

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

Question 10

Which of the following best explains why unsaturated fatty acid tails increase membrane fluidity?

Accepted Answer

They create kinks that prevent tight packing of phospholipids.

Question 11

Facilitated diffusion differs from simple diffusion in that:

Accepted Answer

Facilitated diffusion uses transport proteins to move molecules across the membrane.

Question 12

Which of the following would most likely decrease the permeability of a cell membrane to water?

Accepted Answer

Increasing the proportion of saturated fatty acid tails

Question 13

A Paramecium living in freshwater uses a contractile vacuole to:

Accepted Answer

Pump excess water out of the cell to maintain osmotic balance

Question 14

Which of the following statements about osmosis is correct?

Accepted Answer

Water moves from a region of low solute concentration to high solute concentration.

Question 15

Which of the following is true about channel proteins in the plasma membrane?

Accepted Answer

They provide corridors for specific molecules or ions to cross the membrane.

Question 16

A red blood cell placed in a $$0.9\%$$ NaCl solution (isotonic to the cell) will:

Accepted Answer

Remain unchanged

Question 17

Which of the following would most likely increase the permeability of a cell membrane to small ions?

Accepted Answer

Increasing the number of channel proteins

Question 18

Which of the following best describes the movement of molecules at dynamic equilibrium across a membrane?

Accepted Answer

As many molecules cross the membrane in one direction as in the other.

Question 19

Which of the following is NOT a factor that affects membrane permeability?

Accepted Answer

The genetic code of the cell

Question 20

A cell membrane is described as 'selectively permeable.' What does this mean?

Accepted Answer

Some substances can pass through the membrane more easily than others.

Membrane Structure and Function: Permeability and Transport

Study Guide - Practice Questions

Study Guide - Flashcards