gas exchange in plants

Question 1

Explain the adaptations of leaves for efficient gas exchange

Answer 1

air spaces in spongy mesophyll:
- large surface area for diffusion so it can occur at a faster rate
- short diffusion pathway so there is a faster rate of diffusion

stomata
- lots of stomata so short diffusion pathway to cells (?)

Question 2

Describe gas exchange in a plant when photosynthesis is not taking place

Answer 2

oxygen diffuses into the leaf for respiration, carbon dioxide diffuses out

Question 3

Describe gas exchange in a plant when photosynthesis is taking place

Answer 3

carbon dioxide enters from the air, oxygen diffuses out of the plant

Question 4

Explain why plants have a reduced need for gas exchange with the air than animals

Answer 4

they produce oxygen during photosynthesis which can be used in respiration