6.1 Exchange Between Organisms And Their Environment

Question 1

Do small organisms have a small or large SA:V?

Answer 1

Large

Question 2

Do large organisms have a small or large SA:V?

Answer 2

Small

Question 3

Features of specialised exchange surfaces. (5)

Answer 3

• large SA:V, increase rate of exchange
• thin, short diffusion pathway
• selectively permeable
• movement of environmental medium to maintain a conc. grad.
• transport system, to maintain a conc. grad.

Question 4

What are features found within a transport system?

Answer 4

• transport medium
• pump
• exchange services
• vessels to carry fluid

Question 5

What is the formula for diffusion?

Answer 5

Diffusion = (SA x difference in conc.) / length of diffusion path