Topic 8- exchange and transport in plants

Question 1

Explain how alveoli are adapted for gas exchange by diffusion
between air in the lungs and blood in capillaries

Answer 1

• Thin walls - short diffusion distance
• good blood supply to maintain the concentration gradient
• moist lining for dissolving gasses

Question 2

Factors affecting diffusion :

Answer 2

• distance (diffusion)
• concentration gradient
• surface area

Question 3

How to calculate rate of diffusion using Ficks law

Answer 3

surface area X concentration difference

thickness of membrane

Question 4

Explain the structure of the blood :

Answer 4

• red blood cells carry oxygen , biconcave disc shape for a large surface area
• white blood cells - defend against infections
• platelets help blood clot-small fragments of cells with no nucleus to help clot a wound
• plasma a liquid that helps carry everything in blood - protiesns, horomones, c02, antibodies