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GCSE Biology · key term
The breakdown of dead organisms and waste material into simpler substances.
Used by AQA, Edexcel and OCR
Specification 4.7.2.3 · Paper 2
The breakdown of dead organisms and waste biological material by microorganisms such as bacteria and fungi.
Revise: DecompositionDecomposition is the breakdown of dead organisms and waste biological material. It is carried out mainly by decomposers such as bacteria and fungi. These microorganisms secrete digestive enzymes onto the material, absorb the small soluble products and use some of them in respiration and growth.
Specification 9.13, 9.17B, 9.18B · Paper 2
State that decomposers release carbon dioxide when they respire; decomposition and respiration are connected but are not the same process.
Do not say that hotter or wetter always means faster composting: excessive heat slows decomposition, while waterlogged compost can lose its air spaces.
Keep the carbon transfers in the correct directions: photosynthesis removes carbon dioxide from the atmosphere, whereas respiration, decomposition and combustion release it.
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The breakdown of dead organisms and waste material by decomposers.
Without decomposition, much of the carbon in dead material would remain unavailable to other organisms.
The breakdown of dead organisms, waste or other biological material by decomposers.
The breakdown of dead organic material and waste into simpler substances by decomposers.
Specification B4.1b, B4.1c, B4.1d · Paper 2 (Foundation), Paper 4 (Higher)
The breakdown of dead organisms and waste into simpler substances.
Revise: Role of microorganismsDecomposition breaks this organic material down. Microorganisms, especially bacteria and microscopic fungi, act as decomposers: they feed on dead material and waste and break them into simpler substances.
The breakdown of dead organisms and waste materials, mainly by microorganisms such as bacteria and fungi.
The breakdown of dead organisms and waste materials into simpler substances by decomposers.
Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
Revise: Role of MicroorganismsDecomposition also returns mineral nutrients to the surroundings. For example, nitrogen from organic material can eventually become available in soil as nitrate ions, which plants absorb to make amino acids and proteins. Animals obtain these substances by eating plants or other animals.
The breakdown of dead organisms and waste material into simpler substances, largely by microorganisms.