Osmosis

Question 1

What is osmosis?

Answer 1

The passage of water from a region where it has a higher water potential to a region where it has a lower water through a selectively permeable membrane

Question 2

What is a solute?

Answer 2

Any substance that is dissolved in a solvent.

Question 3

What is a solution?

Answer 3

A solvent and a solute combined.

Question 4

What is water potential?

Answer 4

The potential of water molecules to diffuse out of or into a solution.

Question 5

What does it mean when two solutions are isotonic?

Answer 5

It means both solutions have the same water potential.

Question 6

What factors affect the rate of osmosis?

Answer 6

• Water potential gradient
• Thickness of exchange surface
• Surface area of exchange surface

Question 7

How does water potential gradient affect water potential?

Answer 7

• Higher the water potential gradient the faster the rate of osmosis.
• As osmosis takes place, the difference in water potential on either side of the membrane decreases.
• This results in the rate of osmosis levelling off over time.

Question 8

How does the thickness of the exchange surface affect water rate of osmosis?

Answer 8

• The thinner the exchange surface, the faster the rate of osmosis.

Question 9

How does the surface area of the exchange surface affect rate of osmosis?

Answer 9

Larger the surface area, the faster the rate of osmosis.

Question 10

How can you lower the water water potential of pure water?

Answer 10

Adding a solute.

Question 11

How can you find the water potential of tissues?

Answer 11

• Place cells in a series of solutions of different water potential.
• Where there is no net gain or loss of water from the cells or tissues, the water potential inside the tissues must be the same as that of the external solution