Question 1

Which of the following best describes osmosis?

Accepted Answer

The movement of water molecules from an area of low solute concentration to an area of high solute concentration across a selectively permeable membrane.

Question 2

A red blood cell is placed in a hypotonic solution. What is the most likely outcome?

Accepted Answer

The cell will swell and may burst (lyse) due to water entering the cell.

Question 3

Which of the following statements about plant cells in a hypertonic solution is correct?

Accepted Answer

The vacuole shrinks and the plasma membrane pulls away from the cell wall, a process called plasmolysis.

Question 4

Which of the following best explains why saltwater fish must actively excrete salt through their gills and kidneys?

Accepted Answer

They live in a hypertonic environment, so water tends to leave their bodies by osmosis and salt tends to enter, requiring them to excrete excess salt to maintain homeostasis.

Question 5

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

Accepted Answer

Water will enter the cell, increasing turgor pressure and making the cell firm.

Question 6

Which formula is used to calculate the solute potential ($$\Psi_s) of a $$solution?

Accepted Answer

$$\Psi_s = -iCRT$$

Question 7

Given a 0.2 M NaCl solution at 30°C, what is the value of $$i ($$ionization constant) for NaCl in the solute potential formula?

Accepted Answer

2

Question 8

If the solute potential ($$\Psi_s) of a $$solution is $$-7.48$$ bars and the pressure potential ($$\Psi_p) is$$ $$0$$ bars, what is the water potential ($$\Psi) of $$the solution?

Accepted Answer

$$\Psi = -7.48$$ bars

Question 9

A plant root has a water potential ($$\Psi) of$$ $$-4.6$$ bars. It is placed in a sucrose solution with a water potential of $$-4.87$$ bars. In which direction will water move?

Accepted Answer

Water will move from the root into the solution.

Question 10

Which of the following best describes the function of a contractile vacuole in freshwater protists?

Accepted Answer

It expels excess water that enters the cell by osmosis, preventing the cell from bursting.

Question 11

Which of the following statements about water potential is correct?

Accepted Answer

Water moves from areas of high water potential to areas of low water potential.

Question 12

A beaker contains a 0.3 M sugar solution at 27°C in open air. Using $$i = 1$$, $$C = 0.3$$ mol/L, $$R = 0.0831 L$$·bar/mol·K, and $$T = 300 K$$, what is the solute potential ($$\Psi_s) in $$bars?

Accepted Answer

$$\Psi_s = -7.48$$ bars

Question 13

Which of the following is a real-life example of osmoregulation in animals?

Accepted Answer

Saltwater fish actively excreting excess salt through their gills and kidneys.

Question 14

Which of the following best explains why plant cells do not burst in hypotonic solutions?

Accepted Answer

The cell wall provides structural support and prevents excessive expansion.

Question 15

A freshwater protist is placed in distilled water. What would happen if its contractile vacuole stopped functioning?

Accepted Answer

The cell would swell and eventually burst due to water influx.

Question 16

Which of the following is true about isotonic solutions?

Accepted Answer

There is no net movement of water into or out of the cell.

Question 17

Which of the following best describes the effect of increasing solute concentration on water potential?

Accepted Answer

Increasing solute concentration decreases water potential, making it more negative.

Question 18

A plant cell is placed in a 0.2 M NaCl solution at 30°C. Using $$i = 2$$, $$C = 0.2$$ mol/L, $$R = 0.0831 L$$·bar/mol·K, and $$T = 303 K$$, what is the solute potential ($$\Psi_s) in $$bars?

Accepted Answer

$$\Psi_s = -10.07$$ bars

Question 19

Which of the following is NOT a strategy used by saltwater fish to maintain water balance?

Accepted Answer

Producing large amounts of dilute urine to excrete excess water.

Tonicity & Osmoregulation: Water Balance in Cells

Guida di studio - Domande di pratica

Study guide - Flashcard