7.1 - Specialised Exchange Systems

Question 1

Why do some organisms need specialised exchange surfaces?

Answer 1

• Metabolically active and high demands of oxygen, CO2 etc

- Small SA:V

Question 2

What is the surface area and volume of a sphere?

Answer 2

SA: 4 pi R^2
V: 4/3 pi R^3

Question 3

What are the components of effective exchange surfaces?

Answer 3

• Increased SA: a larger available area for exchange
• Thin Layers: shorter diffusion distances, so faster diffusion
• Good Blood Supply: substances are always moving and this maintains a steep concentration gradient for faster diffusion
• Ventilation: helps to maintain concentration gradients for faster diffusion