Topic 4.1 Surface area to volume ratio

Question 1

How does an organisism’s size relate to their surface area to volume ratio?

Answer 1

The larger the organism, the lower the surface area to volume ratio

Question 2

How does surface area to volume ratio affect transport of molecules?

Answer 2

The lower the surface area to volume ratio, the further distance molecules need to travel to reach all parts of the organism, so diffusion alone is not sufficient

Question 3

Why do larger organisms require mass transport and specialised gas exchange surfaces?

Answer 3

Their small surface area to volume ratio means substances cannot easily enter the cells as in smaller organisms. Mass transport and exchange surfaces facilitate exchange of substances