B1.10 - Exchanging Materials (Finishedish)

Question 1

Give 2 problems to do with exchanging of materials when organisms get bigger?

Answer 1

• Gases and food can’t reach every cell by simple diffusion

- Metabolic waste can’t be removed fast enough to avoid poisoning

Question 2

Give3 adaptions for exchanging materials?

Answer 2

• Having a large surface area over which exchange can take place
• having a thin membrane for a short diffusion path
• Having an efficient blood supply to keep the concentration gradient low
• Being ventilated to make gas exchange more effective

Question 3

How is the small intestine adapted for exchanging substances?

Answer 3

It is covered in millions of little projections called villi which increase the surface are. They also have a good blood supply and a single layer of surface cells

Question 4

How do fish breathe?

Answer 4

Water enters the fish mouth and passes through the gills in which oxygen diffuses to the blood and co2 to the water

Question 5

How are gills adapted for gas exchange?

Answer 5

They have lots of gill filaments with a large surface area covered in lamellae increasing it even more.

Question 6

How are lamellae adapted for gas exchange?

Answer 6

They have lots of capillaries and blood and oxygen flow in opposite ways to increase concentration gradient