BIOL 1361 1nd Edition Lecture 15Outline of Last Lecture I. ComplexesII. Role of O2III. H+ GradientIV. Chemiosmosis and Oxidative Phosphorylation V. ATP SynthaseVI. Cellular Respiration Interaction SummaryOutline of Current Lecture I. Thermodynamics and MetabolismII. Free Energy (G)III. MetabolismIV. EnzymesV. Enzyme ActivityVI. InhibitorsVII. Feedback Inhibition ExampleCurrent LectureI. Thermodynamics and Metabolism (Chapter 6)a. First Law of Thermodynamics: Energy can be transferred of transformed, but cannot be created or destroyed.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.i. Kinetic ii. Potential b. Second Law of Thermodynamics: Every energy transfer or transformation increases entropy of the universe.II. Free Energy (G)a. Definition: Energy available to do workb. Change in energy during a chemical reaction:i. Delta G = Gfinal – Ginitialii. If Gfinal < Ginitial -DeltaGiii. If Gfinal > Ginitial +DelataGc. Exergonic reaction: energy released, spontaneous i. Gfinal – Ginitial is negativeii. Energy of products is lower than energy of reactantsiii. Spontaneous (not fast, but could occur without adding energy)iv. Bigger first column, smaller second columnv. –DeltaGd. Endergonic reaction: energy required, nonspontaneousi. Gfinal – Ginitial is positiveii. Energy of products is greater than energy of reactantsiii. Not spontaneous – energy must be added to make the reaction happeniv. Small first column, bigger second column v. +DeltaGIII. Metabolisma. The sum of all the chemical reactions in the bodyb. Catabolism – breaking down moleculesi. Releases energyii. –DeltaG = Gfinal – Ginitialc. Anabolism – synthesizing complex moleculesi. Requires energy inputii. +DeltaG = Gfinal – GinitialIV. Enzymesa. Structure: All are globular proteinsb. Active Sitei. Part of enzyme that grabs substratec. Function:i. Bind to a substrate – reactant specific for a particular enzymeii. Act as catalysts 1. Decreases activation Energy (EA) – the energy required to start a chemical reaction by pulling and stretching chemical bonds of the substrated. Enzymes are recycled when the reaction is completed – not consumed during thereactionV. Enzyme Activitya. Definition: The rate at which enzyme converts substrate productb. Co-Factors i. Molecules that must attach to the enzyme so it can interact with the substrate1. Ex of co factors: Metal Ions: Mg, Se, Fe, Coc. Conditions: temperature, pHVI. Inhibitorsa. Are molecules that reduce enzymes activityi. Competitive:1. Attaches to the active site and blocks substrate from enteringii. Allosteric:1. Attaches to another region of enzyme2. Changes enzyme shape so active site no longer grabs substrateVII. Feedback Inhibition Examplea. High [Product E]: i. Product E can allosterically inhibit enzyme 1 = attaches to enzyme 1 and inhibits itb. Low [product E]i. Few molecules E attach to enzyme 1ii. Enzyme 1 NOT inhibitediii. Pathway produces more B, C, D, and Ec. Citrate regulates rate of glycolysisd. Allosteric inhibition of phosphofructokinase (PFK)e. [citrate] high, PFK inhibitedf. [citrate] low, PFK
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