Aerobic respiration in such detail as to show that • glycolysis takes place in the cytoplasm and involves the oxidation of glucose to pyruvate with a net gain of ATP and reduced NAD • pyruvate combines with coenzyme A in the link reaction to produce acetylcoenzyme A • in a series of oxidation-reduction reactions the Krebs cycle generates reduced coenzymes and ATP by substrate-level phosphorylation, and carbon dioxide is lost • acetylcoenzyme A is effectively a two carbon molecule that combines with a four carbon molecule to produce a six carbon molecule which enters the Krebs cycle • synthesis of ATP by oxidative phosphorylation is associated with the transfer of electrons down the electron transport chain and passage of protons across mitochondrial membranes.

The first stage of respiration is glycolysis, it happens in the cytoplasm of every cell.

Glucose is phosphorolated (has phosphate groups added) using ATP. This is then split in two to make two triosephosphates. ADP is then used to remove the phosphate and four ATP are created (two from each triose phosphate molecule). NAD is used to remove hydrogen resulting in reduced NAD (NADH). The result of this is two pyruvate molecules.

So we have a net gain of two pyruvate molecules, two ATP and two NADH. These molecules move into the mitachondria.

The pyruvate is then reduced, has carbon removed and has a molecule called coenzyme A added: this makes it into Acetyl CoA.

This process is known as the link reaction as it turns pyruvate into Acetyl CoA ready for the Krebs cycle.

In the Krebs cycle, Actyle CoA joins with a four carbon compound resulting in a six carbon compound, this is then reduced by NAD and FAD, has carbon removed and looses phosphate to ADP.

The result of this is NADH, FADH, two CO2 and one ATP.

NADH and FAD are carrying protons and electrons (because that's what hydrogen is made up of). At the inner membrane of mitachondria there are proteins which take the electrons from NADH and FADH and pass them along; this is known as an electron transport chain. At the end of the electron transport chain the electrons join with hydrogen and oxygen to create water (this keeps the concentration of hydrogen in the matrix low).

As the electrons are being passed along the etc energy is released and this is used to actively transport protons/hydrogens across the inner membrane into the inter-membrane space. Once in this space the protons/hydrogens want to move back over because they are in a higher concentration there than in the matrix; they diffuse back through an enzyme called ATP synthase and as they do so it gives the enzyme the energy to join ADP and Pi to create ATP.