Tropisms
A tropism is a plant growth response to a stimulus, such as growing towards light or roots growing downwards with gravity.
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A tropism is a plant growth response to a stimulus, such as growing towards light or roots growing downwards with gravity.
- Phototropism is growth towards light
- Geotropism is response to gravity
- Controlled by auxin
🧠 Quick quiz
Three questions. Score 2 or more to complete the topic.
What is Tropisms?
Within Biology, which covers cells, the human body, genetics, evolution, plants and ecosystems: the science of living things, this topic explains Tropisms. Biology topics show how living things work, from the cell up to whole ecosystems, with models you can explore step by step.
Check that you can explain Tropisms in your own words and give one example from everyday life. If you can do that, you have understood the core idea.
Understanding Tropisms helps you explain how living things stay alive and respond to their surroundings, which is central to biology exams.
Tropisms in detail
A tropism is a growth response of a plant to a directional stimulus. Phototropism is growth toward or away from light, and geotropism (gravitropism) is growth in response to gravity, so shoots grow upward and roots grow downward.
Auxin, a hormone made in the shoot tip, moves to the shaded side of a shoot, making cells there elongate more, so the shoot bends toward the light. In roots, high auxin inhibits growth, so the root bends down. Tropisms help plants get light for photosynthesis and water and minerals from the soil.
How the interactive helps you understand Tropisms
Click a card to flip it and reveal the answer, then move on to the next one.
Before you change anything, predict the result. Then change one value at a time and check whether your prediction was right. This is a quick way to build a correct mental model of Tropisms.
Real-life uses and examples
- Structure a longer answer about Tropisms by moving from definition to example to consequence.
- Explain how Tropisms helps a living thing stay alive, using a plant or animal example.
- Connect Tropisms to health, food and medicine in everyday life.
Common mistakes to avoid
- Listing the steps of a process without saying how one step causes the next.
- Using everyday words, such as “energy” or “bad”, without their scientific meaning.
- Learning the definition without testing it. Use the quiz and the interactive to check that you can apply the idea.
Frequently asked questions about Tropisms
What is Tropisms?
A tropism is a plant growth response to a stimulus, such as growing towards light or roots growing downwards with gravity.
What are the most important points about Tropisms?
The main points are: Phototropism is growth towards light; Geotropism is response to gravity; Controlled by auxin.
Why is Tropisms useful?
Understanding Tropisms helps you explain how living things stay alive and respond to their surroundings, which is central to biology exams.
How can I practise Tropisms?
Open the interactive at the top of this page and change the controls one at a time. Predict the result before each change, then take the three-question quiz. A score of two or more marks the topic as complete on this device.
Which topics are related to Tropisms?
Related topics in Biology include Respiration, Gas Exchange in Alveoli, The Heart.