How materials are cycled — AQA GCSE Biology
Test yourself on How materials are cycled with AQA GCSE practice questions.
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How materials are cycled explained
In the living world, matter is not destroyed but recycled.
Read the full explanation
Carbon, water, nitrogen, oxygen and mineral ions pass between organisms and the environment. Decomposers break down dead organisms and waste products, releasing mineral ions and carbon dioxide. Producers take up these materials and use them to build new biological molecules. For example, carbon from dead leaves is released as carbon dioxide by decomposition and then fixed by photosynthesis into glucose in a new plant. This recycling provides the building blocks, such as carbohydrates, proteins and nucleic acids, for future organisms. It means ecosystems can continue to support life without a constant new supply of matter.
Your focus
- State that materials in the living world are recycled.
- Describe how decomposers release materials from dead organisms and waste.
- Explain how recycled materials become building blocks for future organisms.
How materials are cycled exam tips
Marking Points
- State that materials in the living world are recycled rather than used up.
- Describe how decomposers break down dead organisms and waste, releasing materials back to the environment.
- Explain that producers take up recycled materials to build biological molecules for growth.
- Give an example of a recycled material, such as carbon from dead leaves becoming carbon dioxide and then glucose in a new plant.
- Explain that recycling provides building blocks for future organisms and supports continued life in an ecosystem.
Examiner Tips
- 💡Use the phrase building blocks and name at least one type of biological molecule in your answer.
- 💡Give a specific example of a material moving from a dead organism to a new organism.
- 💡Avoid saying energy is recycled; state clearly that matter is recycled while energy flows.
Common Mistakes
- Saying materials are lost when organisms die; correction: decomposers return the materials to the environment for reuse.
- Confusing recycling of matter with recycling of energy; correction: matter is recycled, but energy flows through and is lost as heat.
- Thinking only carbon is recycled; correction: water, nitrogen, oxygen and mineral ions are also recycled.