B2.2.1

Question 1

Why is the surface area to volume ratio important

Answer 1

A high surface area to volume ratio means that nutrients can diffuse directly into the organism quickly enough to sustain life, as diffusion distances are small.

Question 2

One way to maximise the exchange surfaces for lungs

Answer 2

To maximise the rate of diffusion of oxygen into the bloodstream, lungs contain many alveoli. These increase the surface area of the lungs.

Question 3

What do villi do

Answer 3

Villi increase the surface area of the intestine wall increases the rate of diffusion.

Question 4

What happens when the required substance has diffused into your body.

Answer 4

It must be transported to where it is needed. This is done using transport systems for example in animals it is the circulatory system and in plants its xylem and phloem.