In aerobic respiration, the glucose food is completely broken down into carbon dioxide and water by oxidation.
Thus, muscle cramps occur due to the accumulation of lactic acid in muscles when the muscles respire an aerobically (without oxygen) while doing hard physical exercise.
We can get relief from cramps in muscles caused by heavy exercise by taking a hot water bath or a massage.
It is called anaerobic respiration because it takes place without air which contains oxygen (‘anaerobic’ means ‘without air’).
The microscopic organisms like yeast and some bacteria obtain energy by anaerobic respiration (which is called! In anaerobic respiration, the micro-organisms like yeast break down glucose (food) into ethanol and carbon dioxide, and release energy. Anaerobic respiration produces much less energy which gets stored in the ATP molecules.
The breaking down of glucose (food) during anaerobic respiration carried out by yeast (plants) can be represented as follows: Please note that during anaerobic respiration (shown above), 1 molecule of glucose (food) produces only 2 energy-rich ATP molecules.
A few organisms such as yeast plants and certain bacteria (called anaerobic bacteria) can obtain energy from food in the absence of oxygen by the process of anaerobic respiration.
Close the mouth of the test-tube with a cork and allow it to stand for some time. A characteristic smell of ethanol (ethyl alcohol) is obtained from the test-tube. When this gas is passed through lime-water, the lime-water turns milky showing that it is carbon dioxide gas.
This experiment tells us that the products of fermentation of sugar brought about by yeast are ethanol and carbon dioxide.
Please note that the whole process of anaerobic respiration takes place in the cytoplasm of cells.
We can carry out the fermentation of sugar by using the anaerobic respiration of yeast as follows: Take some sugar solution (or fruit juice) in a test-tube and add a little of yeast to it.