How many pathways are there for glucose metabolism?
Answer: There are generally three pathways for glucose metabolism: under anaerobic conditions, glucose undergoes glycolysis and produces pyruvate, which is then fermented by lactic acid to generate lactic acid (plants undergo ethanol fermentation to generate ethanol); under aerobic conditions, glucose undergoes glycolysis to generate pyruvate, Pyruvate generates acetyl-CoA in mitochondria, and acetyl-CoA goes through the TCA cycle (or glyoxylate cycle, only plants have) to finally generate carbon dioxide and water; it can also pass through the pentose phosphate pathway to finally generate carbon dioxide and water.