Explain how the structure of cellulose differs from the structure of starch, and explain how these structural differences relate to the different functions of each molecule in plant cells.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Mark scheme (5 marks)
- Cellulose has straight/unbranched chains whereas starch has branched chains (or helical/coiled chains)
- Cellulose chains lie parallel and form cross-links / hydrogen bonds between chains, creating microfibrils
- This gives cellulose high tensile strength / rigidity, so it supports and strengthens the cell wall
- Starch is insoluble, so it does not affect the water potential of the cell / does not cause osmosis
- Starch can be hydrolysed / broken down to release glucose for respiration / energy when needed
Key terms in this question
Related
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