Unit 2: Topic 8 - Tonicity and Osmoregulation

Question 1

What is an isotonic solution, and how does it affect diffusion in a cell?

Answer 1

Isotonic solutions have equal solute concentrations inside and outside the cell, resulting in no concentration gradient and no net flow of water.

Question 2

What is a hypotonic solution, and how does it affect diffusion in a cell?

Answer 2

Hypotonic solutions have lower concentrations of solutes than inside of the cell. This causes the osmosis of water into the cell to equalize solute concentration, which causes the cell to swell.

Question 3

What is a hypertonic solution, and how does it affect diffusion in a cell?

Answer 3

Hypertonic solutions have a higher concentration of solutes compared to the inside of the cell. This causes the osmosis of water out of the cell, shrinking it.

Question 4

A plant cell with a water potential of -6.43 bars keeps a constant volume when placed in a open beaker solution with a solute potential of -2.13 bars. What is the cell’s pressure potential?

Answer 4

The formula for water potential is: (water potential)=(solute potential)+(pressure potential). Using the values given to us in the question we find the equation looks like: -6.43=-2.13+(pressure potential). Adding 2.13 to the left side, we get a pressure potential of -4.3 bars.

Question 5

Is the movement of molecules across membranes essential for homeostasis and cell growth?

Answer 5

Yes, without these movements, nutrients and molecules would not be able to be transported in an efficient way, this would cause issues with a multitude of processes, such as nerve impulses, cell growth, diffusion, and other processes.

Question 6

Are sweating and urination forms of osmoregulation in organisms?

Answer 6

Yes! Sweating and urination are both common forms of osmoregulation in organisms. Urination and sweating helps decrease the amount of water and other waste in the bloodstream.