Gas exchange in plants

Question 1

gas exchange at a stomata

Answer 1

• Oxygen diffuses out of the stomata.
• Carbon dioxide diffused in through the stomata.
• To reduce water loss by evaporation, stomata close at night when photosynthesis wouldn’t be occurring.

Question 2

When the stomata opens and closes what happens to the guard cells.

Answer 2

When the stomata opens the guard cells swell up however when the stomata closes the guard cells shrink.

Question 3

What is the compromise?

Answer 3

Xerophytic plants are adapted to survive in environments with limited water.
They have structural features to enable efficient gas exchange to occur whilst also limiting water loss.

Question 4

What are the features of xerophytes?

Answer 4

• Curled leaves trap moisture to increase local humidity
• Hairs to trap moisture to increase local humidity
• Sunken stomata to trap moisture to increase local humidity
• Thicker cuticle to reduce evaporation
• Longer root network to reach more water.