Aerobic and anaerobic respiration

In a nutshell

Respiration is a chemical reaction that releases energy that the cell can use for other processes. There are two types of respiration; aerobic and anaerobic. Aerobic respiration requires oxygen whereas anaerobic respiration does not require oxygen. Anaerobic respiration can produce different products depending on the organism.

Respiration

Respiration is the process of releasing energy from glucose. This process happens in every cell and the energy released will be used in other processes that happen in the cell. 

Example

Protein synthesis (making proteins) and contracting your muscles. 

Aerobic respiration

Aerobic respiration happens in the mitochondria and requires oxygen. The oxygen reacts with glucose to produce carbon dioxide, water and lots of energy. The oxygen and glucose are called the reactants. The carbon dioxide and water are the products of the reaction. 

​$$glucose + oxygen \rightarrow carbon\ dioxide + water\ (+ energy)$$​​

Anaerobic respiration

Anaerobic respiration is similar to aerobic respiration but it does not require oxygen. It releases less energy than aerobic respiration so it is less efficient. Anaerobic respiration usually only happens when the cells do not have enough oxygen to carry out aerobic respiration. For example, when exercising the muscle cells may not get enough oxygen so they will respire anaerobically.

If this is the case, anaerobic respiration will produce lactic acid. This can build up in your muscles and cause painful cramps like a stitch.

​$$glucose \rightarrow lactic\ acid\ (+ energy)$$​​

Anaerobic respiration can produce different products depending on the organism. In microorganisms such as yeast, anaerobic respiration will produce carbon dioxide and ethanol as well as energy. 

Ethanol is an alcohol and this process of anaerobic respiration producing ethanol is called fermentation. This is also the same process that is used to make beer.

​$$glucose\rightarrow carbon\ dioxide + ethanol\ (+ energy)$$