Diffusion Through Cell Membranes

Question 1

Where does gas exchange happen?

Answer 1

In the lungs.

Question 2

What is the job of the lungs and where does it do it?

Answer 2

To transfer oxygen into the blood and remove waste carbon dioxide from it, it does it by little air sacs called alveoli where gas exchange takes place.

Question 3

How are alveoli specialised to maximise diffusion of oxygen and carbon dioxide? (4 points)

Answer 3

1) enormous surface area
2) moist lining for dissolving gases
3) very thin walls
4) good blood supply

Question 4

Where are the villi?

Answer 4

In the inside of the small intestine.

Question 5

How do villi increase food absorption? (2 points)

Answer 5

1) single layer of surface cells

2) very good blood supply