Question

1) Discuss the role of the stomata in gas exchange

2) Define Photosynthesis

Answer 1

1) Stomata are small pores found on the epidermis of leaves and other soft aerial parts. Each stomatal pore is guarded by two guard cells which function as valves and regulate the size of the pore. The guard cells are rapidly influenced by turgor changes due to their small size and are connected with the adjacent epidermal cells through plasmodesmata. The stomata are located such that, when open, they provide a route for the exchange of gases (mainly carbon dioxide, oxygen, and water vapor) between the internal air space (substomatal space) created by photosynthetic mesophyll cells of the leaves and the bulk atmosphere surrounding the leaf. The cuticle is impermeable to water and the open stomata provide escape route for water vapor from the plant.
2) Photosynthesis is defined as a physico-chemical process by which plants use light energy and synthesize carbohydrates from carbon dioxide and water in the presence of chlorophyll. It is thus a process by which light energy is converted to chemical energy. Photosynthesis leads to the formation of carbohydrate molecules, which serves as a primary source of fuel for living things.