3.3.1 SA:V

Question 1

what is the equation covering the rate of exchange by diffusion across a surface?

Answer 1

(surface area x change in concentration)/distance = rate of diffusion

Question 2

what is the relationship between size, SA:V and rate of diffusion?

Answer 2

• as size increases.
  -surface area to volume ratio decreases.
• rate of diffusion decreases.

Question 3

what is the relationship between SA:V and metabolic rate?

Answer 3

• decreasing surface area to volume ratio (increasing size).
• metabolic rate decreases.
• rate of heat loss decreases.

Question 4

why are most exchange surfaces internal in the body?

Answer 4

• protect from damage (as surfaces are thin and need support).
• reduce heat and water loss.