iGCSE Biology (0610)-8.2 Water uptake - iGCSE Style Questions Paper 1

Question

The diagram shows the movement of water molecules from a plant leaf to its environment. Two processes have been numbered.

Which row identifies the numbered processes?

▶️ Answer/Explanation

The diagram illustrates the pathway of water loss from a leaf, known as transpiration. Process $1$ occurs when liquid water on the damp surfaces of mesophyll cells turns into water vapor in the air spaces; this phase change is evaporation. Process $2$ shows the movement of that water vapor from the high concentration inside the leaf’s air spaces to the lower concentration in the external atmosphere through the stomata. This net movement of gas molecules down a concentration gradient is diffusion. Therefore, the sequence matches row B.
✅ Answer: (B)

Question

The roots of a plant are cut off and the stem is placed in a beaker containing a liquid red stain.

After a few hours, in which part of the plant stem will the red stain be visible?

(A) cuticle
(B) phloem
(C) style
(D) xylem

▶️ Answer/Explanation

The red stain acts as a proxy for water movement within the plant. In vascular plants, the xylem is the specialized tissue responsible for the upward conduction of water and dissolved minerals from the base to the leaves. Even without roots, the transpiration pull and capillary action continue to draw the liquid up through these hollow, tube-like vessels. The phloem, conversely, transports organic nutrients (sucrose), while the cuticle is a waxy outer layer and the style is part of the flower’s reproductive system. Therefore, the red dye will only be seen accumulating in the xylem vessels.
✅ Answer: (D)

Question

What is the pathway taken by water from the soil to the leaf?

A) root hair cells → root cortex → mesophyll → xylem
B) root hair cells → root cortex → xylem → mesophyll
C) root cortex → root hair cells → mesophyll → xylem
D) root cortex → root hair cells → xylem → mesophyll

▶️ Answer/Explanation

Solution

Ans: B

The correct pathway of water from the soil to the leaf is:

Root hair cells absorb water from the soil.
Water moves through the root cortex (via osmosis and apoplastic/symplastic pathways).
It enters the xylem (vascular tissue) for upward transport.
Finally, water diffuses into mesophyll cells in the leaf for photosynthesis.

Option B is correct because it follows this sequence. The other options misorder the steps (e.g., xylem cannot come after mesophyll, as xylem transports water to leaves).

iGCSE Biology (0610)-8.2 Water uptake – iGCSE Style Questions Paper 1

Question

Question

Resources

Members

Company