Home / iGCSE Biology (0610)-8.3 Transpiration – iGCSE Style Questions Paper 1

iGCSE Biology (0610)-8.3 Transpiration – iGCSE Style Questions Paper 1

IGCSE Biology (0610) Practice Questions Paper 1 - All Chapters

Question

Which processes occur during transpiration?

  1. Water diffuses from the air spaces into the mesophyll cells.
  2. Water evaporates from surfaces of mesophyll cells into air spaces.
  3. Water from air spaces evaporates through stomata.
  4. Water vapour from air spaces diffuses through stomata.
(A) 1 and 3
(B) 1 and 4
(C) 2 and 3
(D) 2 and 4
▶️ Answer/Explanation

Transpiration begins with liquid water evaporating from the moist surfaces of mesophyll cells into the intercellular air spaces (process 2). This water vapor then diffuses out of the leaf through the stomata, driven by a concentration gradient (process 4). Process 1 describes the reverse movement (into cells), which does not occur during transpiration. Process 3 incorrectly states that evaporation happens through stomata; evaporation occurs at the cell surfaces inside the leaf, not at the stomata.

✅ Answer: (D) 2 and 4

Question
Which graph shows the effect of increasing wind speed on the rate of transpiration?
Graph Options
▶️ Answer/Explanation
Solution

Ans: A

Increasing wind speed enhances the rate of transpiration by removing the moist air around the stomata, creating a steeper water vapor gradient. This causes more water to evaporate from the leaf surface.

Graph A correctly depicts this relationship, showing a steady rise in transpiration rate as wind speed increases. The other graphs either show no effect (B/C) or a decrease (D), which contradicts biological principles.

Question

The diagram shows the pathway of water molecules through a leaf and out to the environment.

mesophyll cell → process X → air space → process Y → stomata

Which statements are correct?

  1. Process X is active transport.
  2. Process X is evaporation.
  3. Process Y is diffusion.
  4. Process Y is osmosis.

A) 1 and 3
B) 1 and 4
C) 2 and 3
D) 2 and 4

▶️ Answer/Explanation
Solution

Ans: C

Process X (mesophyll cell → air space): Water evaporates from the mesophyll cell surfaces into the air spaces. This is evaporation (Statement 2), not active transport (Statement 1 is incorrect).

Process Y (air space → stomata): Water vapor diffuses out through the stomata. This is diffusion (Statement 3), not osmosis (Statement 4 is incorrect).

Since Statements 2 and 3 are correct, the answer is C (2 and 3).

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