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Plant hormones (biology only)
Study how plant hormones coordinate growth responses to light and gravity and how plant hormones are used in agriculture and horticulture.
19
Objectives
10
Flashcards
10
Questions
90 min
Study time
AqaGcseBiologyHomeostasis and response
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Syllabus checklist
What you need to know
19 objective pages available
Control and coordination11 objectives
- Describe plant hormones as chemicals that coordinate and control plant growth and responses.
- Explain that plants respond to light and gravity using unequal distributions of plant hormones.
- Describe phototropism as a plant growth response to light.
- Describe gravitropism, or geotropism, as a plant growth response to gravity.
- Explain how unequal distribution of auxin causes unequal growth in shoots and roots.
- Explain (HT only) that gibberellins are important in initiating seed germination.
- Explain (HT only) that ethene controls cell division and fruit ripening.
- State (HT only) that the detailed mechanisms of gibberellin and ethene action are not required.
- Carry out Required Practical 8 by investigating the effect of light or gravity on the growth of newly germinated seedlings.
- Record plant growth data using length measurements and labelled biological drawings.
- Apply safe and valid practical design to plant-response investigations, including control variables, repeats, light direction and gravity treatment.
Use of plant hormones (HT only)8 objectives
- Describe (HT only) the use of auxins as selective weed killers.
- Describe (HT only) the use of auxins as rooting powders for plant cuttings.
- Describe (HT only) the use of auxins in tissue culture.
- Describe (HT only) the use of ethene to control fruit ripening during storage and transport.
- Describe (HT only) the use of gibberellins to end seed dormancy.
- Describe (HT only) the use of gibberellins to promote flowering.
- Describe (HT only) the use of gibberellins to increase fruit size.
- Evaluate (HT only) agricultural and horticultural uses of plant hormones, including benefits, risks and effects on biodiversity.
Key terms
plant hormonescoordinationPhototropismGravitropismphototropismlightgravitropismgeotropismauxinunequal growthgibberellinsseed germination
Exam tips
- Understand Plant Hormones: Remember to memorize the key types of plant hormones and their functions in coordinating growth and responses. Link your answer to Control and coordination in Plant hormones (biology only), and keep the biology specific to plant hormones.
- Understand Plant Hormone Distribution: Remember to focus on how unequal distributions of plant hormones like auxin influence plant responses to light and gravity. Link your answer to Control and coordination in Plant hormones (biology only), and keep the biology specific to gravity.
Common mistakes
- Misunderstanding the Role of Plant Hormones: Emphasize that plant hormones are chemicals that not only promote growth but also coordinate and control various responses in plants, such as phototropism and gravitropism.
- Misunderstanding Plant Hormone Distribution: To fix this, students should focus on understanding how auxins are distributed differently in response to light and gravity, leading to varied growth rates in different parts of the plant.
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