Exchange Across Cell Membranes - Osmosis

Question 1

What is osmosis?

Answer 1

Osmosis is the diffusion of water molecules across a partially permeable membrane, from an area of higher water potential to an area of lower water potential

Question 2

What is water potential?

Answer 2

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

Question 3

What has the highest water potential?

Answer 3

Pure water

Question 4

What are two solutions called that have the same water potential?

Answer 4

Isotonic

Question 5

What three things affect the rate of osmosis?

Answer 5

1. The water potential gradient
2. The thickness of the exchange surface
3. The surface area

Question 6

How does the water potential gradient affect the rate of osmosis?

Answer 6

The higher the water potential, the faster the rate of osmosis. As osmosis takes place, the difference in water potential of either side of the membrane decreases over time, so the rate of osmosis levels off

Question 7

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

Answer 7

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

Question 8

How does the surface area affect the rate of osmosis?

Answer 8

The larger the surface area, the faster the rate of osmosis