Question

The schematic depicts an unexpanded plant cell within a hypocotyl with the arrangement of cellulose microfibrils marked on its cell wall.

• A. A
• B. B
• C. C
• D. D

Hint:

Remember: Cellulose fibrils act like hoops around a barrel. They block expansion in the direction they run and force expansion in the perpendicular direction.

Answer 1

The Correct Option is A

Step 1: Role of cellulose microfibrils.
In plant cell walls, cellulose microfibrils are inextensible structures that determine the direction of cell expansion.
Cell growth is anisotropic: the wall expands perpendicular to the orientation of the cellulose fibrils, while expansion parallel to the fibrils is restricted.
Step 2: Orientation in the given schematic.
In the figure, the cellulose fibrils are oriented mostly in a horizontal manner (transverse relative to the cell’s vertical axis).
This orientation restricts lateral expansion and promotes elongation in the vertical direction.
Step 3: Resulting cell shape.
If the fibril pattern does not change, the hypocotyl cell will primarily elongate longitudinally, becoming a taller rectangular cell.
This corresponds to option (A).
Therefore, option (A) is correct.