3.3.1 Surface Area to Volume Ratio

Question 1

What is the relationship between the surface area and volume of an organism?

Answer 1

As the size of an organism increases: volume increases more than surface area increases

Question 2

What is the environment around cells of multi cellular liquid?

Answer 2

Tissue fluid

Question 3

What organisms require a larger volume to surface area ratio?

Answer 3

Organisms with a higher metabolic rate exchange more materials so require a larger surface area to volume ratio

Question 4

How have large organisms evolved to speed up the rate of diffusion?

Answer 4

A flattened shape so no cell is far from the surface

Specialised exchange surfaces with large surface areas

Question 5

What are the characteristics of specialised exchange surfaces?

Answer 5

Large surface area relative to volume
Very thin so diffusion distance is reduced
Selectively permeable to allow selected materials across
Movement of the environmental medium maintains the concentration gradient
A transport system to ensure the moment of the internal medium

Question 6

How do you have to represent the surface area to volume ratio?

Answer 6

Surface Area : Volume as SA : 1