Bio Notes

Bio Notes - 2/17/09 *Temperature is a measure of: kinetic...

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2/17/09 *Temperature is a measure of: kinetic energy *Heat is the measure of: total energy *An enzyme catalyzed reaction generally____ its rate for a 10 degree C temperature increase? Doubles Regulation of enzyme activity - How are enzymes controlled? - Can they be turned on and off? Competitive enzyme inhibition - Substrate and inhibitor compete for binding to the active site of the enzyme - Inhibitor is structurally similar to the substrate - Most apparent at low (Substrate) Noncompetitive enzyme inhibition - Inhibitor binds at a site away from the substrate binding site - Causes a conformational change in the enzyme - Not overcome by increasing the substrate Allosteric enzyme regulation - “other site” - Modulator (activator or inhibitor) binds to a site other than the substrate binding site (active site) - Causes a conformational change of the enzyme which changes the activity Cooperativity
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- Oxygen binding to hemoglobin - 4 oxygen binding sites - Binding alters the affinity for O2 - Binding of the first O2 makes it more favorable for the next O2 to bind How do cells regulate metabolism? - Chemical transformations in small steps - Each step catalyzed by a specific enzyme *How is a pathway turned off? Turn off the first enzyme *The first enzyme of the pathway is allosterically regulated. Why not competitive inhibition? The pathway product is dissimilar from the substrate for the enzyme Why Allosteric inhibition? - Typically an enzyme catalyzes a small change - The product of a pathway may be very different from the starting material o Won’t be a good fit as a competitive inhibitor - Therefore inhibit at an “other” site o Allosteric inhibition RedOx Reaction - Reduction-Oxidation reactions - Biological RedOx Reactions involve transfer of electrons and hydrogens - Biological RedOx Reactions employ carrier molecules: coenzymes/cofactors o Cycle between the reduced and oxidized forms o = “Reducing power” of the cell Cofactors/Coenzymes
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- NAD (oxidized form) - NADH (reduced form) - NADP (oxidized form) - NADPH (reduced form) - FAD (oxidized form) - FADH2 (reduced form) Another control problem - Some processes require energy and “reducing power” - Some produce energy and “reducing power” - Some break down biological molecules - Some build biological molecules - How are these organized into an orderly system? Spatial Separation
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This note was uploaded on 08/22/2010 for the course BIOL 1201 taught by Professor Wishtichusen during the Spring '07 term at LSU.

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Bio Notes - 2/17/09 *Temperature is a measure of: kinetic...

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