Plants

• What are the 2 main processes that plants carry out?

  Photosynthesis and respiration.
• How is a short diffusion pathway created in plant leaves?

  Leaves are very thin.

  There are many stomata on the underside of a leaf so no cell is far from a stoma.
• How is the mesophyll layer of a leaf adapted for gas exchange?

  The surface area of the cells is large so faster diffusion.

  There are air spaces between the cells, so gases can come into contact with mesophyll cells more readily.
• Similarities between gas exchange in plants and insects:

  1. Diffusion takes place in the gas phase, faster than if it were in water.
  2. No living cell is far from the external air, and therefore a source of CO2 and O2.