B2 : Transpiration

Question 1

Stomata

Answer 1

Small openings in the leaves of plants

Question 2

Guard cells

Answer 2

Control the opening and closing of the stomata, when the plant has a lot of water, the vacuoles of the guard cells are full and the plant cells become turgid forcing the guard cells apart opening the stomata. The opposite happens when the plant is low in water. Stomata can open when plants need to carry out gas exchange

Question 3

Gas exchange in the leaves

Answer 3

CO2 from the atmosphere diffuses into air spaces and into the photosynthesizing cells. Oxygen moves the opposite direction out of the cells into the air spaces and out into the atmosphere

Question 4

Transpiration

Answer 4

When the stomata are open, gases and water vapor can be lost through the stomata by diffusion. This is known as transpiration. Due to water loss being a side effect of stomatal opening, it is important that plants can close their stomata to limit water vapor loss