2.34 Describe the differences between aerobic and anaerobic respiration

Aerobic respiration is when an organism respires using oxygen and glucose is completely and fully broken down. This is used for movement, growth, etc. in humans. It is how we respire most of the time. This may be different in other organisms, or the same.

glucose + oxygen → carbon dioxide + water (+ energy)

Anerobic respiration is when an organism respires without using oxygen. Yeast, for example, naturally respires anerobically. In humans, however, we respire anerobically when the heart and lungs cannot work fast enough to provide enough oxygen around the body to break down that glucose. Instead, the body does not use oxygen, providing a fast, short burst of energy. This causes the build up of lactic acid (a waste product) in our muscles, which sometimes makes them sore. After respiring anerobically, as a human, you breathe heavily to make up for the oxygen lost. This can occur in other organisms too but may be different.

glucose → lactic acid (+ energy)

Figure 1: When you sprint, you respire anerobically. (Yes, that is Usain Bolt.)