The process by which the glucose is split into two molecules of pyruvic acid is called glycolysis. It occurs in cytoplasm. The two molecules of pyruvic acid formed from a glucose molecule move into mitochondria and are oxidized, decarboxylated to two molecules of acetyl coenzyme A (acetyl Co-A). This acetyl Co-A is the connecting link between glycolysis and Krebs cycle. Acetyl Co-A thus formed participates in citric acid cycle (Krebs cycle) and combines with oxaloacetic acid to form citric acid.

Tamil Nadu Botany Text, Class: XII, Unit 2: Plant physiology, Page no: 202, 204 and 205.