Aerobic Respiration

• Aerobic respiration is a chemical process by which energy is released from glucose in living organisms. It involves the breakdown of glucose for energy with the use of oxygen.

• This process takes place in living cells and is vital for life as it provides energy needed for biological functions such as muscle contraction and maintaining constant body temperature.

• The word ‘aerobic’ refers to the presence of oxygen, showing that oxygen is needed for this type of respiration to occur.

• The overall process can be summarised by the equation: glucose + oxygen –> carbon dioxide + water + energy.

• Specifically, aerobic respiration involves four main stages: Glycolysis, Link Reaction, Krebs Cycle, and Oxidative Phosphorylation.

• Glycolysis, the first stage, takes place in the cytoplasm. It involves splitting a molecule of glucose into two molecules of pyruvate. Some ATP is produced and NAD is reduced to NADH.

• The Link Reaction and Krebs cycle occur in the mitochondria. The pyruvate molecules undergo a series of reactions, leading to further ATP production, the reduction of more NAD to NADH, and also the reduction of FAD to FADH2. The waste product of these stages is carbon dioxide.

• The final stage, Oxidative Phosphorylation, takes place in the inner mitochondrial membrane and involves the electron transport chain. This is where most of the ATP (energy) is produced. It requires the presence of O2 which acts as the final electron acceptor, binding with free protons to create water.

• Remember that aerobic respiration is more efficient than anaerobic respiration (which happens without oxygen) and yields much more ATP per glucose molecule. However, both types of respiration are essential for life.

• Regular testing and recall of key concepts such as stages and locations of processes within aerobic respiration will aid understanding and retention. Be sure to practise and familiarise yourself with relevant diagrams.