BIOL 212 Lecture Notes - Lecture 19: Acetyl-Coa, Citric Acid Cycle, Metabolic Pathway
Document Summary
Occurs in stepwise fashion, allows for capturing some of released energy as opposed to releasing energy all at once and losing it as heat. Comes in form of food, and fat and glycogen stores. Plants store energy as starch and fats. Breakdown of large macromolecules to monomers outside cells or in lysosome (digestion) Cellular catabolism in cytoplasm (oxidation of small organic molecules) 10 separate reactions, each catalyzed by different enzyme. 2atp and 2 nadh produce for each glucose molecule. 3 phases: energy investment, cleavage of 6-carbon sugar to 2 3-carbon sugars, energy generation. Can occurs by siphoning off product in metabolic pathway (sequential reactions) or enzymatically linking two reactions via common intermediate. Both cases highly favorable reaction drives unfavorable reaction. Step 2 glycolysis unfavorable: siphoning effect drives reaction. Steps 6 and 7 involve energetically unfavorable reactions: nad+ + h- nadh, adp + pi atp, use reaction coupling, 1,3-biphosphoglycerate used. Acetyl group of acetyl coa fed into cycle.
