Science (086) — AI-generated practice question

When a sensitive plant (Mimosa) is touched, the information is communicated from cell to cell using electrical-chemical means, even though there is no specialised nervous tissue. The cells at the point of movement then change their shape by changing the amount of water in them — cells swell or shrink, causing the leaves to fold.

This is fundamentally different from animal muscle movement. In animals, muscle cells contain specialised proteins that change their shape and arrangement in response to nervous electrical impulses, causing the muscle cell to shorten. In plants, no such proteins exist; movement depends entirely on changes in water content (turgor) of cells.

Source: Chapter 6, Section 6.2.1 (Immediate Response to Stimulus) and Section 6.1.4 (How does the Nervous Tissue cause Action?)

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• 3 marks = 3 key points: (1) electrical-chemical communication between cells in plants, (2) plant cell movement via water gain/loss (turgor change), (3) contrast with animal muscles using specialised proteins.
• Examiners expect the phrase "no specialised tissue" for plants and "special proteins" for animal muscles — these are direct textbook terms.
• Don't confuse this with growth-based movement (tropism); Mimosa folding is growth-independent.
• Mentioning "turgor" or "swelling/shrinking" scores the movement mark; mentioning "special proteins shorten the cell" scores the animal-muscle mark.