Respiration is when the Glucose made in photosynthesis is then released from cells in a series of chemical reactions.
There are two types of respiration: Anaerobic and Aerobic.
Anaerobic Respiration:- This type of respiration does not require oxygen, it produces lactic acid. It creates less energy per glucose molecule than aerobic respiration. Anaerobic respiration is used in plants and microorganisms with little or no oxygen in them e.g Yeast. The word equation for anaerobic respiration is: glucose → lactic acid (+ energy released)
Aerobic respiration:- It requires oxygen and occurs in the mitochondria of cells. the word equation is the opposite to that for photosynthesis :
glucose + oxygen → carbon dioxide + water (+ energy). It is used to contract muscles in animals and keep a constant body tempurature in birds and mammals.
Yeast and Bacteria
Bacteria has circular DNA
In Yeast and some bacteria sugars are converted into ethanol in Anaerobic respiration. This is called fermentation.
When fermentation is performed on a larger scale using yeast, water, sugar and some other nutrients bio-ethanol can be made that can be used as a fuel.