16.3.3

Gibberellins & DELLA Proteins

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Gibberellins & DELLA Proteins

Gibberellins are plant hormones that help regulate seed germination. They exert this control by triggering the breakdown of a class of repressor proteins called DELLA proteins.

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Role of gibberellins

  • Gibberellins have an important role in triggering seed germination.
  • Gibberellins do this by triggering the production of the enzyme amylase.
    • Amylase allows seeds to breakdown their starch reserves into glucose. The glucose can then be used to provide energy through respiration.
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Gene control

  • When a seed absorbs water, it triggers the production of gibberellins.
  • Gibberellins then break down DELLA proteins.
    • DELLA proteins are repressor proteins that bind to and inhibit a transcription factor that promotes amylase transcription.
  • Once gibberellins have triggered the breakdown of DELLA, the transcription factor is liberated.
  • The transcription factor can then bind to the promoter region of the amylase gene.
  • There is then increased transcription of amylase and then seed germination.

Jump to other topics

1Cell Structure

2Biological Molecules

3Enzymes

4Cell Membranes & Transport

5The Mitotic Cell Cycle

6Nucleic Acids & Protein Synthesis

7Transport in Plants

8Transport in Mammals

9Gas Exchange

10Infectious Diseases

11Immunity

12Energy & Respiration (A2 Only)

13Photosynthesis (A2 Only)

14Homeostasis (A2 Only)

15Control & Coordination (A2 Only)

16Inherited Change (A2 Only)

17Selection & Evolution (A2 Only)

18Classification & Conservation (A2 Only)

19Genetic Technology (A2 Only)

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