Respiration is a process of releasing energy from glucose (sugar). There are two types of respiration: aerobic respiration and anaerobic respiration.
Just to clarify: respiration is not breathing – that is scientifically called ventilation.
What is aerobic respiration?
Aerobic respiration involves oxygen. Glucose and oxygen react to produce energy, carbon dioxide and water. Below is the chemical equation for this:
glucose + oxygen → (energy +) carbon dioxide + water
The mitochondria (which is in the cell’s cytoplasm) is where this usually happens.
What is anaerobic respiration?
Anaerobic respiration doesn’t involve oxygen. It usually happens during heavy exercise when not enough oxygen can reach the muscles. For humans, this is the chemical equation for anaerobic respiration:
glucose → lactic acid
The main downside to anaerobic respiration is it doesn’t produce as much energy as aerobic respiration. It also produces a waste product: lactic acid, which can cause muscle pain and tiredness. This acid can only be broken down when aerobic respiration starts again.
But it’s not just humans that use anaerobic respiration. Micro-organisms, such as bacteria, also use anaerobic respiration. It is also used when baking bread: the yeast in bread allows fermentation to happen, using the following chemical equation:
glucose → ethanol (alcohol) + carbon dioxide
What is this energy used for?
The energy generated from respiration is used for:
- controlling body temperature (in animals)