Step 1:  Citrate Synthase:  Entry of substrate by condensation with oxaloacetate.

Step 2:  Aconitase:  Rearrangement

Step 3:  Isocitrate dehydrogenase:  First oxidative decarboxylation.

Step 4:  Alpha-Ketoglutarate dehydrogenase complex:  Second oxidative decarboxylation

Step 5:  Succinyl-CoA Synthetase:  Substrate-level phosphorylation.

Step 6:  Succinate dehydrogenase complex:  Sustrate-level phosphorylation

             Q= FAD
Step 7:  Fumarase:  Hydration

Step 8:  Malate dehydrogenase:  Oxidation

This reaction results in the creation of:
2 molecules CO2
1 molecule ATP  (used by the body as energy)
3 molecules NADH  (used to create ATP)
1 molecule FADH2  (used to create ATP)

Purdue University, West Lafayette, IN
http://chemed.chem.purdue.edu/organic/orgapp/body_energy/citric_acid/citric.html

Step 1:

Step 2:

Step 3:

Step 4:

Step 5:

Step 6:

Step 7:

Step 8:

This is a cycle - now the oxaloacetate produced in Step 8 can be used again in Step 1, and the process can reoccur.