When we breathe, our bodies use some of the oxygen we take in for respiration. Cells in our bodies use this oxygen to break down the glucose and turn it into energy.
Aerobic respiration is the release of energy from glucose using oxygen. It is a controlled energy release unlike the energy released from burning a substance in oxygen although the two are very similar.
The word equation for aerobic respiration is below:
Glucose + Oxygen = Carbon Dioxide + Water + Energy
Aerobic respiration takes place in almost all living things however some organisms can survive in the absence of air. When your muscles start working in a short running race for example they carry out aerobic respiration. When you cannot get enough oxygen into your body during a long distance race your muscles may start using anaerobic respiration and produce lactic acid. It is this lactic acid that makes muscles cramp. Anaerobic produces less energy than aerobic respiration. Glucose is only partly broken down into alcohol or lactic acid when oxygen is not present.
Many microbes use anaerobic respiration, yeast can respire with or without oxygen. When it respires without oxygen, it is called fermentation. The word equation for anaerobic respiration of yeast s below:
Glucose = Alcohol + Carbon Dioxide + Energy