B2.2.1 - Exchange & Transport

Question 1

What is SA:V?

Answer 1

Surface area to volume ratio

Question 2

What does a large SA:V indicate?

Answer 2

Organisms with a large SA:V are more likely to rely on diffusion for transport

Question 3

Name 3 adaptations (by multi cellular) to increase ratio of SA:V

Answer 3

1) Larger surface area for a higher diffusion rate
2) Having a thin membrane (short diffusion pathway)
3) Efficient blood supply/good ventilation (creates a steep gradient, higher diffusion rate)

Question 4

Name 3- 4 adaptations in multi cellular organisms to: INCREASE SURFACE AREA

Answer 4

• LUNGS: alveoli creating large approx. 75m squared
• SMALL INTESTINES: millions of villi increasing surface area (get digest food into blood)
• FISH GILLS: contain lamellae
• LEAVES: flat shape/air spaces inside allows more CO2 in cells

Question 5

Name 2 adaptations in multi cellular organisms to: THIN MEMBRANE

Answer 5

• LUNGS: alveoli and capillaries have extremely thin walls
• SMALL INTESTINE: villi have single cell thick layer

Question 6

Name 2 adaptations in multi cellular organisms to: EFFICIENT BLOOD SUPPLY/VENTILATION

Answer 6

• LUNGS: constant oxygen supply, oxygenating blood from alveoli and capillaries
  
  • Constant process
• FISH: water flows in one direction, blood in other/oxygen concentration higher in water