In step five, one molecule of GTP is created. Succinate is also created. Succinate dehydrogenase allows for the removal of two hydrogen atoms from the previously mentioned product succinate. In such a step, FADH2 is created, and the new product is fumarate. Step seven is not an oxidation step.
Water is added through the help of fumarase, and fumarate is changed into malate.
The last step, which is once again an oxidation step, malate dehydrogenase carbon 2 is converted into a carbonyl group. This creates another molecule of NADH and produces oxaloacetate, which is needed to restart the citric acid cycle. In anaerobic organisms, the citric acid cycle does not occur, instead fermentation occurs. The citric acid cycle is also known as tricarboxylic acid cycle or the Krebs cycle. The citric acid cycle does not directly utilize oxygen, however it is still necessary in order for it to proceed.