BCM 475 Lecture Notes - Lecture 22: Citric Acid Cycle, Phosphocreatine, Atp Hydrolysis
Document Summary
A thermodynamically unfavorable reaction is made favorable by being coupled to a very thermodynamically favorable reaction. Energy released from atp is used to drive reactions that need energy input. Why is atp used for energy transfer: reduction of electrostatic repulsion, resonance stabilization of adp and p1, hydration of adp and p1 is better than that of atp. Atp is more unstable than stable atp hydrolysis is thermodynamically favored: this is due to the high activation energy barrier. Glycolytic intermediates | transfer phosphoryl group to atp during glycolysis. Creatine phosphate | energy reserve in vertebrate muscle: provides the atp necessary during the first 4 sec of a sprint. Atp is regenerated through oxidation of fuel molecules. Majority of atp is made in oxidative phosphorylation. During oxidation of fuel, e- are transferred to e- carriers: phosphate carriers (atp, electron carriers (nadh, fadh2, carbon carriers (acetyl coa) Both nad+ and fad are used as high-energy e- carriers through many metabolic pathways.
