12Alecture+8+small+grey

12Alecture+8+small+grey - Life is a catalyst that catalyzes...

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Life’s±Catalysts: ±The±structure,±func5on,±and±cost±of proteins Chap.±8,±Chap.±3.1±and±3.2 Progress of a reaction Energy of products (= people, plants…) Δ G Released energy Transition state A,B <-> C,D Energy of fuel, photons, chemicals of high G Life is a catalyst that catalyzes its own synthesis? Products±are±catalysts! Life uses energy from fuel and light to: turn simple materials into cell mass to pump nutrients in to move to do work. This is work accomplished by a huge number of individual catalysts (maybe 3500? for a bacterium ( E. coli )) These dictate all the metabolic capabilities we’ve talked about. Autotrophs, heterotrophs, fermenters, respirers, photosynthesizers, anaerobes, aerobes, differ in what catalysts they possess and therefore what reactions they can perform. The catalysts of modern life are mostly PROTEINS (ENZYMES) Other proteins are structural, pumps, “wires”, machines, regulators Structure is complicated Synthesis is complicated The underlying principles are quite simple Origins are hard to imagine When life originated, it must have used simpler catalysts. Look in modern life forms for clues to the past. Every reaction we’ve discussed has an enzyme …
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Why does life use a catalyst for every reaction? Why does life use a catalyst for every reaction? a) To make it go faster. b) To emphasize the rare useful reactions and avoid toxic alternatives. c) To tune pathways so rates are compatible. d) To optimize rates for ambient conditions . e) To allow it to compete by employing a specialized lifestyle. f) All of the above Why does life use a catalyst for every reaction? a) To make it go faster. What’s the hurry? (Why are trees tall?) b) To emphasize the rare useful reactions and avoid toxic alternatives- ( 162 metabolites out of 14 million possibilities ) c) To tune pathways so rates are compatible- Pathways are amazingly complex in plan d) To optimize rates for ambient conditions - Things change -- competition is Ferce e) To allow it to specialize on a lifestyle distinct from its competitors- (Hide from competition) Answer(s)’hidden’here Questions For Today: 1. How do biological catalysts (proteins) make catalytic binding surfaces? 2. How do you measure catalytic ability of enzymes? 3. Why are proteins so expensive to make? Questions for another day: 1. How do you control catalyst behavior? 2. How does modern life make proteins? 3. How can life improve a catalyst? 4. How can life add a new catalyst? 5. How were the Frst protein catalysts made?
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How do enzymes do what they do? Proteins are made of amino acids, but enzymes often carry cofactors that participate in catalysis *’These “coenzymes ”’are simply’substrates- they±re’not’enzymes. *
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If enzymes are all about “perfect fit” how does life build a shape to match the substrate?
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12Alecture+8+small+grey - Life is a catalyst that catalyzes...

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