Lecture 11 Flow of Energy A. Introduction - Living organisms To be alive, we need energy Being an organized, moving organism requires energy We can't make our own energy - Transformation We can only transform energy B. Energy transformation 1. Energy - The ability to do work 2. Types - Living organisms convert types of energy from one form to another 1) Radiant energy, a.k.a. - Electromagnetic energy - Comes from the sun 2) Electric energy 3) Chemical energy - Bonds - Glucose (C6H12O6) 4) Sound energy 5) Mechanical energy 6) Heat energy - Some chemists say heat is a process, not energy 3. Thermodynamics - The study of energy transformation - &quot;Thermo&quot; = &quot;heat&quot; - &quot;Dynamics&quot; &quot;moving&quot; 4. 1st Law of Thermodynamics - Conservation of energy The total energy in the universe is constant You can change energy from one form to another, but energy cannot be created or destroyed - H = G + TS H = enthalpy - The total amount of energy - Doesn't change G = free energy - Useful energy - We can do work with free energy because it is unstable - Has a gradient T = temperature S = entropy - Useless energy - Disorder - We cannot do work with useless energy because it is stable nd 5. 2 Law of Thermodynamics G (free energy) = H (enthalpy) TS (entropy) Describes the direction of change Disorder (entropy) is increasing The potential energy of the final state (products) &lt; the potential energy of the initial state (reactants) If entropy is always increasing, the amount of free energy is always decreasing Universe is going downhill (crash in and explode); life will end because without a difference in heat, you can't do work - Exergonic (fig. 7-5) Energy out (release energy) Also called spontaneous a reaction that will go more than halfway without input of energy Potential energy of the final state &lt; the potential energy of the initial state - Thermodynamically favorable because it's in agreement with the 2nd Law of Thermodynamics - How do you recognize an exergonic reaction? Catabolism - we take something big and break it down into something small (hamburger [protein]) amino acids - Endergonic Energy in (input of energy) Not spontaneous Not thermodynamically favorable (unfavorable; not in agreement with the 2nd Law of Thermodynamics) - Potential energy of the initial state &lt; potential energy of the final state Example: anabolism small parts built into larger part; (amino acids our proteins) ATP (<a href="/keyword/adenosine-triphosphate/" >adenosine triphosphate</a> ) + H2O ADP (adenosine diphosphate) + <a href="/keyword/inorganic-phosphate/" >inorganic phosphate</a> - Favorable because is something is exergonic, the product should be less organized (has extra phosphate) We get lots of energy from the above reaction, but we can't use it all 6. Living systems - We are considered endergonic It takes energy to keep us organized Without energy, we become H2O + CO2 - Initially, we get energy from solar (radiant) energy Photosynthesis chlorophyll electronic energy chemical energy(glucose) - Bonds (respiration) We can do aerobic respiration to break glucose down Overall, we get energy from aerobic respiration 7. Coupled reactions - We can't perform an exergonic reaction without performing an endergonic reaction as well - Oxidation reduction reaction Oxidation = loss of electrons/H+; oxidized Reduction = gain of electrons/H+; reduced - Sometimes a proton (such H+) travels with electron - Hydrogen has more energy than H+ because it is more organized Photosynthesis 6 CO2 + 12 H2O + light &amp; chlorophyll C6H12O6 + 6O2 + 6 H2O - The overall equation for photosynthesis - The CO2, is reduced, because CO2 gain a H+ - Photosynthesis is endergonic (unfavorable) - H2O is oxidized, because it loses H+ to glucose - Reactant have to be oxidized or reduced , not products C. Energy Carrier Compounds and Electron Acceptor Compounds 1. Energy Carrier Compounds (fig 7-5) - <a href="/keyword/adenosine-triphosphate/" >adenosine triphosphate</a> (ATP) - Adenine nitrogenous base - Ribose 5 C sugar - Phosphate 3 phosphate groups - GTP = guanosine triphosphate ATP ADP + Energy (endergonic) 2. Electron Acceptor Compound (fig. 7-7) - Nicotinamide <a href="/keyword/adenine-dinucleotide/" >adenine dinucleotide</a> NAD+ o Capable of accepting 2 electrons + a proton o Oxidized Form NADH o Reduced form o Has more energy Nicotinamide Adenine NAD+ NADH -