Science (086) — AI-generated practice question

When a sensitive plant is touched, the information is transmitted from cell to cell through electrical-chemical signals. This information reaches the cells at the base of the leaf (pulvinus). These cells change their shape by changing the amount of water in them — some cells lose water and shrink while others swell, causing the leaf to fold and droop. Unlike animal muscle cells, which use specialised proteins, plant cells rely entirely on this osmotic change (gain or loss of water) to alter their shape and bring about movement.

Source: Chapter 6, Section 6.2.1 — Immediate Response to Stimulus

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• The examiner expects three key points: (1) electrical-chemical signal transmission, (2) cells at the leaf base change shape, and (3) shape change occurs due to change in water content (swelling/shrinking) — NOT by specialised proteins like in animals.
• Avoid confusing this growth-independent movement with tropic movements (like phototropism), which involve auxins and cell elongation.
• The term "pulvinus" is a bonus but not required for full marks in Class 10.