2Alecture+8

But this is not a viable soluon for living things 1

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Unformatted text preview: ff ­ allowing the cell to express just those biochemical pathways that it needs at the moment •  Life is ALL ABOUT regula>on of metabolism ­ and choosing the right pathway for the job. But this is not a viable solu>on for living things 1 1/24/10 Catalysts For example… •  Catalysts take part in a reac>on, and speed it up, but emerge from the reac>on with no permanent chemical change. glucose  ­> pyruvate (glycolysis) Stay in cytoplasm ? Fermenta>on Move to mitochondrion •  An inorganic example is solid MnO2, which will very quickly change to H2O2 to H2O and O2. A li_le chunk of MnO2 can last you a life>me ­ it never gets “used up”. Pyruvate oxida>on This is a major decision ­ the cell must interpret signals from the environment, and then appropriately tune enzymes and transporters up and down. •  Transi>on metals (metals that are very flexible about their oxida>on state) oaen catalyze redox reac>ons ­ this is true for biological reac>ons, too. The metal provides a shortcut for the electron to travel from reductant to oxidant. Citric acid cycle Respira>on So do all catalysts work through metals? No, they have other tricks, too… REACTANTS BIND TO A SURFACE 1.  2.  3.  4.  5.  Specific features -- specific binding– SUBSTRATE SPECIFICITY Binding restricts motion/vibration/flex Same average energy distributed between fewer states Helps keep reactants close (less energy required to provide collisions) Binds stretche...
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This note was uploaded on 06/13/2013 for the course BIS 2A taught by Professor Grossberg during the Winter '08 term at UC Davis.

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