*GAS EXCHANGE IN PLANTS (2)

Question 1

How are the air spaces in the spongy mesphoyl layer adapted for gas exchange?

Answer 1

increases the Surface area:Volume ratio for the ABSORPTION of carbon dioxide

Question 2

How is the guard cells around the stomata adapted for gas exchange?

Answer 2

• -)allows the SIZE of the STOMATA to be ADJUSTED
• -)to ALLOW the DIFFUSION of gases
• -)e.g OPENS DURING the day to ALLOW the diffusion of carbon dioxide for photosynthesis

Question 3

How does the leaf having a flat shape increase gas exchange?

Answer 3

• -)large SA to absorb MORE LIGHT

- -)and carbon dioxide for photosynthesis

Question 4

How does the leaf being thin increase gas exchange?

Answer 4

THIN =SHORTER DIFFUSION DISTANCE for carbon dioxide to diffuse INTO leaf cells
–)and for oxygen and water vapour OUT of the leaf

Question 5

How does the leaf having stomata increase gas exchange?

Answer 5

• -)Can OPEN to ALLOW diffusion of carbon dioxide INTO the leaf for photosynthesis
• -)and the diffusion of OXYGEN and WATER VAPOUR out of the leaf