The Krebs cycle (also known as the citric acid cycle or the tricarboxylic acid cycle) is a biochemical process through which organisms can generate energy (in the form of ATP, or adenosine triphosphate) by oxidizing acetate that comes from other biomolecules (sugars, fats, and proteins). Since it uses oxygen, it is called an aerobic process. The Krebs cycle also generates other molecules, such as NADH (nicotinamide adenine dinucleotide), that are used in other biochemical processes. The names citric acid cycle and tricarboxylic acid cycle come from the fact that citric acid is used up and then regenerated in the reactions in the cycle. The name Krebs cycle is named after Hans Adolf Krebs, who was one of its discoverers.