"To understand the Krebs Cycle, visualize a circle with eight points. The Krebs Cycle is like an 8-cylinder car engine. Each of those eight points is a chemical, an organic acid, which is essential to the creation of energy. Those eight organic acids are citrate, cis-aconitate, isocitrate, alpha-ketoglutarate, succinate, fumarate, malate, and oxaloacetate."... see the rest in the link....