Explain how ethene and gibberellins are used by plants, and describe one commercial use of each hormone.

AQA GCSE Biology (8461) — 4.5.4 Plant hormones (Bio only) · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

Ethene is a gaseous hormone that controls cell division and the ripening of fruits. Commercially it is used to ripen fruit after transport, for example bananas are exposed to ethene in warehouses to speed up ripening.

Gibberellins are hormones that initiate seed germination. Commercially they are used to break seed dormancy, for example in agriculture to ensure uniform germination of crops, or in brewing to promote germination of barley.

Examiner tips

  • Use the exact terms ‘cell division’ and ‘ripening of fruits’ for ethene, and ‘initiate seed germination’ for gibberellins.
  • Give a clear commercial example for each hormone.
  • Keep the answer concise and to the point to fit the 4‑mark allocation.

Common mistakes

  • Confusing ethene with ethylene or using the wrong word for the hormone.
  • Failing to mention the commercial use or giving a non‑specific example.
  • Using vague language such as ‘helps plants grow’ instead of the specific actions required.

Mark scheme (4 marks)

  1. Ethene controls cell division / controls the ripening of fruits
  2. One commercial use of ethene — e.g. used to ripen fruit after transport / used to ripen bananas in the warehouse
  3. Gibberellins initiate seed germination
  4. One commercial use of gibberellins — e.g. used to end seed dormancy / used to produce larger fruit / used in brewing to promote germination of barley

Key terms in this question

ethene · gibberellins

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