Tricarboxylic acid cycle does not occur in:

The electron transpo and oxidative phosphorylation systems and the enzymes required for the citric acid cycle are located in the mitochondria of cells, which are the major source of ATP for energy-consuming reactions in most tissues.The citric acid cycle does not occur in all cells.For example, mature human red blood cells do not contain mitochondria and the cycle is absent.In these cells, ATP is formed by the anaerobic conversion of glucose to lactate (anaerobic glycolysis).