What happens to a glucose molecule once it enters the blood stream?

Glucose is needed for cellular respiration to provide energy. The blood takes it to cells, and if oxygen is present, the glucose goes into the mitochondria to undergo cellular respiration. It is burned with oxygen to produce ATP (energy), H2O, and CO2

actually the glucose enters the cells is coverted to glucose -6-Phosphate is degraded by glycolysis to pyruvate and in aerobic tissues the pyruvate enters the mitochondrion and is converted by pyruvate dehydrogenase to acetyl CoA which then condenses with oxaloacetate via the enzyme citrate synthase to form citrate which begins the Krebs" TCA Cycle. The products of Krebs"( NADH and FADH2 ) enter the electrion transport system and by a series of step down oxidations results in the production of ATP during respiration ( oxidative phosphorylation ) and water ( oxygen is the terminal oxidant and becomes reduded to water ).