Krebs cycle is also commonly referred to as the citric acid cycle. It plays an integral role in the cellular respiration process and the term “Krebs” has been named after Hans Krebs. The whole cycle comprises of a series of dynamic chemical reactions that aerobic organisms make use of in order to generate energy. The biochemical pathway of Krebs cycle suggests that it might possibly be one of the first parts related to the metabolism of a cell that evolved. Before understanding Krebs cycle, let us briefly go through what a link reaction is. This is one of the most important parts of the evolution process of a cell and is also known as Pyruvate Decarboxylation or Swanson Conversion. As per this reaction, a linkage is formed between glycolysis and Krebs cycle or citric acid cycle through metabolic pathways.