I'm doing AQA B and all i've learnt (all you need to learn) is that the Kreb Cycle takes place in the matix of the mitochondria and acetyl coenzyme A reacts with a 4- carbon compound to produce a 6- carbon compound. 2xCO2 formed, and reduced NAD and FAD, and a small amount of ATP. Thats the Kreb Cycle, try to draw a diagram it helps.
you don't need to know it in too much detail for aqa...... :
acetylcholine (AcetylCoA)........react with 4- carbon acid, and becomes 6-carbon molecule.......this is oxidised........2 moleclues os CO2 come off, and molecules of NAD and FAD are reduced