The Krebs cycle, also known as the citric acid cycle or TCA cycle, occurs in the mitochondrial matrix of eukaryotic cells. This matrix is the dense fluid inside the mitochondria that contains the enzymes, coenzymes, and other molecules necessary for the cycle's biochemical reactions

. In prokaryotic cells, which lack mitochondria, the Krebs cycle takes place in the cytosol instead

. Thus, in typical animal and plant cells, the Krebs cycle occurs specifically within the mitochondrial matrix.