Small nonpolar gases such as O\textsubscript{2} and CO\textsubscript{2}

$$\Psi_s = -2 \times 0.2 \times 0.0831 \times 298 = -9.9$$ bars

Question 1

Which statement best describes the Fluid Mosaic Model of the plasma membrane?

Accepted Answer

The membrane consists of a mosaic of proteins and phospholipids that are constantly moving and changing.

Question 2

Which type of molecule can most easily pass through the hydrophobic center of the phospholipid bilayer?

Accepted Answer

Small nonpolar gases such as O	extsubscript{2} and CO	extsubscript{2}

Question 3

What is the primary function of aquaporins in cell membranes?

Accepted Answer

To move water rapidly into and out of cells

Question 4

A red blood cell is placed in a hypotonic solution. What is most likely to happen?

Accepted Answer

The cell will swell and may burst (cytolysis).

Question 5

Which of the following best defines tonicity?

Accepted Answer

The ability of a solution to cause a cell to gain or lose water based on solute concentration.

Question 6

Water moves from a region of ______ water potential to a region of ______ water potential.

Accepted Answer

higher; lower

Question 7

What is the equation for calculating water potential?

Accepted Answer

$$\Psi = \Psi_s + \Psi_p$$

Question 8

If a plant cell is placed in distilled water, what prevents it from bursting?

Accepted Answer

The cell wall exerts a back pressure (turgor pressure)

Question 9

Which of the following is true about solute potential ($$\Psi_s$$)?

Accepted Answer

Adding solute makes solute potential more negative.

Question 10

Calculate the solute potential ($$\Psi_s) of a 0.2 M $$NaCl solution at 25°C. Use $$i = 2$$, $$R = 0.0831$$ liter bar/mole K, and $$T = 298 K.$$

Accepted Answer

$$\Psi_s = -2 	imes 0.2 	imes 0.0831 	imes 298 = -9.9$$ bars

Question 11

A freshwater fish lives in a hypotonic environment. What adaptation helps it maintain osmotic balance?

Accepted Answer

Its gills actively pump ions in and it urinates frequently.

Question 12

Which property of water allows it to act as a universal solvent?

Accepted Answer

Its polarity

Question 13

What will happen to a plant cell placed in a concentrated salt solution?

Accepted Answer

Its cell body will shrink and pull away from the cell wall (plasmolysis).

Question 14

Which of the following is NOT a property of water?

Accepted Answer

High density as a solid

Question 15

A cell with a water potential of $$-2.5$$ bars is placed in a solution with a water potential of $$-1.0$$ bars. In which direction will water move?

Accepted Answer

Water will move out of the cell.

Question 16

Which equation is used to calculate solute potential ($$\Psi_s$$)?

Accepted Answer

$$\Psi_s = -iCRT$$

Question 17

Why do grocery stores spray water on their vegetables?

Accepted Answer

To plump up the cells by creating a hypotonic environment

Question 18

Which of the following best explains why cells are so small?

Accepted Answer

Smaller cells have a higher surface area to volume ratio, allowing for more efficient exchange of materials.

Question 19

Which of the following is a direct result of water's polarity?

Accepted Answer

Water molecules form hydrogen bonds with each other.

Membrane Structure, Transport, Tonicity, Osmosis, and Water Potential

Study Guide - Practice Questions