B4d - Diffusion And Osmosis

Question 1

What is osmosis?

Answer 1

When the water moves in and out of plant cells through the cell membrane

Question 2

What does the cell wall do?

Answer 2

Provides support

Question 3

Osmosis is a type of what?

Answer 3

Diffusion

Question 4

What is diffusion?

Answer 4

The movement of smelling particles, through particles of air, to an area where they are at a lower concentration.

Question 5

Explain how leaves are adapted to increase the rate of diffusion of carbon dioxide and oxygen

Answer 5

Leaves are thin to reduce the distance that gases have to diffuse through. They are broad with a spongy layer inside to provide a large surface area.

Question 6

Explain why there are differences in the effects of water uptake and loss on plant and animal cells.

Answer 6

Plant cells have a strong rigid cell wall on the outside of the cell membrane. This stops the cell bursting when it absorbs water by osmosis.
If a red blood cell is placed in water, water enters the cell by osmosis. Because the membrane is quite weak the cell will burst as the volume and therefore the pressure in the cell increases. Red blood cells shrink when placed in concentrated solutions of sugar as water moves out of them by osmosis. This makes the cells appear wrinkled when viewed through a microscope.