Respiration Respiration is a chemical reaction that occurs in the cells of all living organisms. Aerobic respiration (uses oxygen) releases energy from glucose and produces the waste products carbon dioxide and water.
Word equation Glucose + Oxygen
Chemical equation C6
H12 O6 + 6O2 Carbon dioxide + Water + Energy 6CO2 + 6H2 O + Energy
Decomposition Decomposition is the way in which living organisms, mainly bacteria and fungi (e.g. mushrooms), break down dead organic matter or waste. Decomposition releases the nutrients contained in the organic matter into the environment. It is a vital part in the recycling of many elements, including carbon and nitrogen. These elements are released into the atmosphere or the soil and absorbed by the roots of plants to make plant tissue.
Fig. 5 Mushrooms are fungi that feed on dead plant matter.
Combustion Combustion (burning) of wood and fossil fuels releases heat energy from the fuel using oxygen. Carbon dioxide and water vapour are produced.
Decomposition Process whereby dead organisms are broken down into simpler substances.
Combustion The release of heat energy from a fuel using oxygen.
Fig. 6 Combustion releases energy from a fuel using oxygen.
Word equation Fossil fuel + Oxygen (e.g. Methane)
Chemical equation CH4
+ 2O2 Combustion
Carbon dioxide + Water vapour + Heat energy Combustion
