Form 5 Biology KSSM 17.2 Main Organ for Gaseous Exchange

What is the function of stomata in plants?

• Supporting the plant structure

• Photosynthesis

• Water absorption

• Gas exchange

Why are stomata important in plant physiology?

• Regulate temperature in the plant

• Aid in seed dispersal

• Help in water absorption

• Regulate gas exchange and facilitate photosynthesis

How is potassium involved in stomatal opening?

• Potassium has no role in stomatal opening

• Potassium ions cause guard cells to shrink and close the stomatal pore

• Potassium ions trigger the uptake of water by guard cells, leading to their swelling and the opening of the stomatal pore.

• Potassium ions inhibit the uptake of water by guard cells

Discuss the role of sucrose in regulating stomatal opening.

• Sucrose causes guard cells to become rigid, preventing stomatal opening.

• Sucrose has no effect on stomatal opening or closing.

• Sucrose causing water to enter the guard cells and leading to their swelling and subsequent stomatal opening.

• Sucrose acts as a deterrent, causing guard cells to shrink and leading to stomatal closure.

Explain the relationship between turgor pressure and leaves wilting.

• Turgor pressure helps maintain the rigidity of the leaves, so a decrease in turgor pressure can cause leaves to wilt.

• Wilting of leaves has no relation to turgor pressure

• Turgor pressure has no effect on leaves wilting

• Leaves wilt due to excessive turgor pressure

What happens to stomata during the day and night?

• They open at night and close during the day

• They open during the day and close at night.

• They remain closed during the day and open at night

• They open and close randomly throughout the day and night

How does environmental factors such as light and humidity affect stomatal opening?

• Triggering the movement of guard cells

• Reducing the movement of guard cells

• Increasing the size of stomata

• Causing the death of guard cells

Describe the process of transpiration and its relation to stomata.

• Transpiration is the process of water movement through a plant and its evaporation from the air. Stomata are large openings on the surface of stems that allow for gas exchange and water vapor to escape during transpiration.

• Transpiration is the process of water movement through a plant and its evaporation from the soil. Stomata are small openings on the surface of flowers that allow for gas exchange and water vapor to escape during transpiration.

• Transpiration is the process of water movement through a plant and its evaporation from aerial parts, such as leaves, stems and flowers. Stomata are small openings on the surface of leaves that allow for gas exchange and water vapor to escape during transpiration.

• Transpiration is the process of water movement through a plant and its evaporation from underground roots. Stomata are large openings on the surface of leaves that allow for gas exchange and water vapor to enter during transpiration.

Discuss the impact of stomatal closure on plant water loss.

• Reduces the transpiration rate and decreases water loss

• Causes an increase in water uptake and water loss

• Has no impact on transpiration rate or water loss

• Increases the transpiration rate and increases water loss