<p> AP Biology: Energy & Enzymes figure references from chapter 6, Campbell & Reece, Biology 6th ed.</p><p>Metabolism -metabolism is the process of managing energy resources of the cell -anabolic pathways vs. catabolic pathways</p><p>Energy -energy is the ability to do work (transport materials, mechanical movement, push unfavorable chemical reactions) -kinetic energy & potential energy (chemical is a type of potential energy) -measurement of energy (Calorie vs. calorie) fyi: the sun produces 4x1016 (40,000,000,000,000,000) Calories/sec.!</p><p>Energy as it relates to organisms -based on red-ox reactions (OILRIG) -the importance of the electron (e-) -reduced form has higher energy (how / why?) -cellular respiration is essentially the process of synthesizing ATP by harvesting energy containing e- from food</p><p>Thermodynamics Conservation of Energy (1st law of thermodynamics) Entropy (2nd law of thermodynamics) -what is the relationship between entropy and heat? -energetically, why do some phenomena happen naturally? (water flowing downhill as opposed to up) Free energy-amount of energy available to break bonds or do work</p><p>Exergonic & Endergonic Reactions (fig 6.6, 6.12) -How are they different conceptually? -How and why do they appear differently when graphed? -Why don’t exergonic reactions happen instantly?...what keeps the reactants from immediately becoming products? -What is activation energy?...biologically, is it good, bad, or both?...why?</p><p>Exergonic Endergonic</p><p>Adenosine Triphosphate (ATP) (fig 6.8)</p><p>ATP Structure -“high energy” bonds 3- -small amount of energy is required to hydrolyze a PO4 bond…why? -significant energy is released when the hydrolysis occurs…why?</p><p>ATP+ H2 O� ADP Pi Result -ATP hydrolysis is highly exergonic ( DG = -7.3 kcal/mol at STP) -ATP powers cellular processes by coupling favorable exergonic reactions with unfavorable endergonic reactions -great for short term energy storage, not long term, due to instability</p><p>Alan Cotten, Fossil Ridge High, KISD- Energy & Enzymes: Campbell & Reece 6th ed Enzymes: Biological Catalysts </p><p>Characteristics of Enzymes -enzymes are biological catalysts that greatly increase the rate of reaction -factors affecting rate of reaction… trivia: how fast on average?...fastest? -temperature 1000/sec, 600,000/sec -concentration of enzymes -concentration of substrate -enzymes are catalysts and therefore by definition are not “used up” in a reaction</p><p>-enzymes lower activation energy (EA) by “stressing bonds” or by providing a favorable environment for the reaction to proceed</p><p>Structure & Function: How do enzymes work? (fig 6.15) Enzyme Structure -active sites -allosteric sites -“the rest”</p><p>Enzyme Function -lock and key vs. induced fit models of enzyme activity -enzymes are proteins and therefore have a “window of life” specific to their environment -temperature -pH & ion concentration</p><p>Enzymes: Effect of Temperature & pH</p><p>Control of enzymes Inhibitors -competitive & noncompetitive (allosteric) (fig 6.17) -cofactors (inorganic) & coenzymes (organic) -many vitamins are coenzymes or precursors of coenzymes -NAD+ & FAD cofactors…more on these in the cellular respiration chapter -medical implications of inhibitors?...penicillin, etc.</p><p>Activators -opposite of inhibitor…turns on an enzyme -activators bind to allosteric sites</p><p>Regulating biochemical pathways (fig 6.19) -positive feedback -negative feedback inhibition</p><p>Alan Cotten, Fossil Ridge High, KISD- Energy & Enzymes: Campbell & Reece 6th ed</p>