Biology

Glucose + Oxygen ----> Carbon dioxide + Water (+ energy)

Most reactions in aerobic respiration take place inside the mitochondria

The energy released in respiration is used to make muscles contract

It is also used by mammals and birds to maintain their body temperature

In plants the energy is used to build up sugars, nitrates and other nutrients into amino acids which can then be built up into proteins

During exercise:

• The heart rate increases
• The rate and depth of breathing increases
• The arteries supplying the muscles dilate

This means that respiration can occur more efficiently and at a higher rate

When muscles are fatigued and insufficient oxygen is reaching them they use anaerobic respiration to get the energy they need

Glucose -----> lactic acid + energy

Anaerobic respiration does not produce as much energy as aerobic respiration because the breakdown of glucose is incomplete

It results in an oxygen debt

This has to be repaid to oxidise the lactic acid into carbon dioxide and water