Introduction to Cellular Respiration

Cellular respiration is the releasing of energy (usually from glucose). This happens in animals, green plants, fungi and bacteria. This energy is needed for processes like growth, movement, repair, sensitivity and reproduction.

Aerobic respiration is the most efficient form, and requires oxygen. Some organisms can respire anaerobically when there is a lack of oxygen.

Yeast respires both aerobically and anaerobically. Aerobic is better for it, as it can get more energy, however is doesn't die in a lack of oxygen, it simply switches to anaerobic respiration. However, when yeast respired anaerobically, it produces ethanol(alcohol), which will eventually kill the yeast.

Humans too respire in 2 ways. Aerobic being the main respiration method. But for example, when a race is being run we cannot get enough oxygen to our cells, so the muscles respire anaerobically and produce lactic acid as a by-product. If we produced alcohol like yeast, (then we would be drunk!) Lactic acid causes cramps.

2 Important equations:

Glucose + Oxygen -> Carbon Dioxide + Water + Energy
Glucose -> Carbon Dioxide + Ethanol + Energy