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Small molecules are assembled into polymers, which may be hydrolyzed later as the needs of the cell change. Please provide me an example…right now. What is it? How many chemical reactions at any given time? Examples of metabolic pathways? Light Energy Kinetic energy Heat, or thermal energy Potential energy Chemical energy Energy - The capacity to cause change Kinetic energy - energy associated with the relative motion of objects. Heat, or thermal energy – the kinetic energy associated with random movement of atoms or molecules. Potential energy - energy that matter possesses because of its location or structure. Chemical energy – used in biology to refer to the potential energy available for release in a chemical reaction. Metabolism manages material and energy resources (studying the latter is known as bioenergetics) throughout the cell or cells in an organism using grouped chemical reactions called metabolic pathways. What does managing material and energy resources mean? Two kinds of pathways help with this “management” – either breaking down (catabolic) or building up (anabolic). When groups of anabolic and catabolic reactions (pathways) work together and transfer energy, we say they are energy coupling. What do we study? Where do we study them? What do we call the matter under study? What do we call everything else? What kind of system are you? Are you phlying in the phace of the second law of thermodynamics? “Organisms are islands of low entropy in an increasingly random universe.” Chemical reactions and free energy. Free energy is available for work, but the system that contains it needs a little push. ΔG = ΔH – TΔS Spontaneous reactions cause the system they happen in to lose free energy. Where does the lost energy go? Enzymes lower the push that is needed by lowering the activation energy (EA). Provide a place where conditions allow for substrate to react more easily (for both catabolic and anabolic reactions in metabolic pathways). Go to animation on website… Exergonic reactions release free energy (like burning wood), but in our bodies, we harness most of it as ATP through a series of enzyme catalyzed reactions. Because they release free energy, a - ∆G results which means these reactions make energy available to be harnessed. Endergonic reactions use free energy harnessed from exergonic ones in the form of ATP (remember that free energy has other forms than ATP). Because they take up free energy, a + ∆G results which means these require energy to proceed. How come we never reach equilibrium? Metabolic disequilibrium is maintained because we constantly exchange materials with the environment. Recall that bioenergetics is the study of energy management in living things. Management of energy in living things usually comes as a result of coupling downhill and uphill reactions. Energy that would have been lost as heat in the breakdown of glucose is conserved when it is transformed to ATP. ATP supplies the energy for most cellular processes. What are they? Enzymes are catalytic proteins. What does every chemical reaction between molecules involve? Get up to the top! HOT STUFF! The laws of thermodynamics favor the breakdown of large highly ordered molecules such as… Thank goodness for activation energy. On the other hand, we need some reactions to happen for life to persist. What are our options without enzymes? Because they have an ___________. When reactants (known as __________) bind with the enzyme, an _________ results. What does the induced fit cause? They cause a change in the position of key parts of active site that can make it easier for the reaction to occur (because it lowers _________). How is the substrate usually held in the active site? What decides which way the enzyme will allow a reaction to progress? So dang fast! What are they? Orient the substrate molecules so they are more likely to react. Putting physical stress on the bonds of the substrate – getting them closer to the ______________ state? Creating chemical microenvironments. Participating in the catalytic reaction by doing what? Enzymes have 3D shape. An unfolding of the enzyme means it has been ____________. What kinds of environmental conditions can do this? The temperature or pH that enzymes work best at are called ___________ temperature or pH. Thermus aquaticus, your stomach, your cells, etc. Cofactors. What are they? What’s the difference between cofactors and coenzymes? Coenzymes are typically _____________. How do they help? What about inhibitors? Where do the work? Competitive and non-competitive ones. Toxins are irreversible. Sarin and acetylcholinesterase – what’s the big deal? Why can’t enzymes run amok? We can regulate the genes that code for them or we can regulate them once they’ve been made. Allosteric regulation can do two things. What are they? Inhibit or activate the enzyme. What level of protein folding have we reached with allosteric enzymes? Why? Allosteric inhibition/activation cooperativity