MCELLBI 100B Lecture Notes - Lecture 19: Blood Sugar, Hepatocyte, Gluconeogenesis
3 May 2020
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Document Summary
It"s regulation/function is fundamental to physiology and pathology: these pathways can be engineered for fuel, materials, and pharmaceuticals. Sugar metabolism is a two way street: carbohydrates must also be synthesized de novo (gluconeogenesis, glycolysis can be reversed depending on conditions, variation between kingdoms, but you can"t beat the laws of thermodynamics. Is gluconeogenesis thermodynamically possible: three highly exergonic steps, the pyruvate kinase reaction is essentially irreversible in the cell, solution is to bypass these reactions. The final steps are driven forward, again, by burning atp. Both reactions are favorable in the cell? glucose+2adp+2pi +2nad+ 2 pyruvate + 2atp + 2nadh + 2h+ + 2h2o. 2 pyruvate + 4atp + 2gtp + 2nadh+2h+ +4h2o glucose + 4adp + 2gdp + 6pi + 2nad+ Futile cycles could happen: burn atp oof, all these reactions if reversed would be burning atp. Big picture: the liver regulates glucose levels: maintain blood glucose levels.
