BIOLOGY 207 1st Edition Lecture 3 Outline of Previous Lecture I. Impact of molecular phylogeny on biologyII. Eukarya, Archaea, BacteriaOutline of Current Lecture I. Thermodynamics of Redox ReactionsII. Characterization of Energy MetabolismCurrent LectureEnergeticsThe transition from phylogeny to energetic is possible because all groups of life require some form of energetic to have the energy to survive. Individual molecules are constantly inputting energy as organized systems. I. Thermodynamics of redox reactionsa. What are redox reactions?i. Oxidation reactions: donate/lose electrons ii. Reduction reactions: gain/accept electronsiii. Both are relevant in the division and energetic of cellsb. Electron donors are the more electronegative molecules, whose electrons flow tothe more electropositive moleculesc. With organic life, these reactions give off energy, where oxygen is reduced and organic compounds are oxidizedd. Given the electronegativities of each of different molecules, you can find the Gibbs free energy value (∆G)i. Positive values: endorgonic (energy is absorbed by the reactionii. Negative values: exergonic (energy is given off and captured by the surrounding)iii. ∆G0 = -nF∆E01. n = # of electrons transferreda. found by determining the oxidation state of the elements in the reactants and productsb. when molecules are reduced they gain electronsThese 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.c. when molecules are oxidized, they lose electronsd. elements in their elementary substances are 0, meaning they have no chargei. eg: H2O is made up of 2 Hydrogens, each of which have a +1 charge, and 1 Oxygen which has a -2 charge; the sum is 0, meaning that there is a total charge of 0/no charge2. F = Faraday constant, 96.48 kJ/V3. ∆E0 = difference in redox potentialsiv. Determine the relationship between ∆G and ∆E1. How many electrons are released when glucose is oxidized? C6H12O6 + 6O2 à 6 CO2 + 6H2OGlucose oxidation half reaction: C6H12O6 + 6H2O à 6CO2 + 24p+ + 24e-Oxygen reduction half reaction: 6O2 + 24p+ + 24e- à 12H2O 2. Aerobic Respiration of Glucose a. Electron Transport Chain (ETC): electrons flow trhoguh carriers from the cytoplasm out, exiting the chain by reducing the terminal electron acceptor (O2)b. NAD+/NADH carry protons and electrons, making it a carrier to generate ATPGlucose:oxidizedOxygen: reducedc. ATPase: ATP synthase, present in all forms of life to processand generate energyd. Summary of ATPase mechanism: http://www.youtube.com/watch?v=PjdPTY1wHdQ e. NAD+ is reduced to NADH in the citric acid cycle, whereaerobic respiration gets most of its reducing poweri. The NADH then splits again in the citric acid cycleinto NAD+ and an electron and donates theelectron to the ETCii. The NAD+ then goes back to being reduced andcreates more NADH for the ETC to create moreenergyf. Glycolysis breaks glucose down into pyruvate by using thecitric acid cycle and ETC to regenerate NAD+ and cycle it inand out of the cytoplasmII. Characterization of Energy Metabolism a. Two different energy sourcesi. Light1. Mechanism: Phototrophya. Microbes that utilize light: Phototrophs ii. Chemicals1. Mechanism: Chemotrophya. Microbes that utilize organic chemicals (eg. glucose,acetate, etc.): chemoorganotrophs ADP + PiATPMembraneF1OutInb2F0c12aβαγδβεααb. Microbes that utilize inorganic chemicals (eg. H2, H2S, NH4+,etc.): chemolithotrophsb. Characterizations of microbes by source of energy, electrons and carbon:Energy Electrons CarbonPhoto Litho AutoChemo Organo Heteroi. Naming the organisms by energy source goes through the previous tables categories 1. Autotrophs: CO2 as primary Carbon source2. Heterotrophs: organic compounds as primary Carbon sourcec. Fermentation: the anaerobic catabolic catabolism of an organic compound in which the compound serves as both an electron donor and acceptori. If there is no electron acceptor, the molecules can still break down energyii. The following image shows glycolysis as a redox reaction to NAD+, which then reduces to NADH then dumps the electrons to pyruvateiii. ATP is made by substrate level phosphorilation, not ATPaseiv. Fermentative organisms run ATPase in reverse, pumping ATP out1. Proton Motor Force: used for transport and motilityd. Metal cofactorsi. Many common ETC components include metal cofactors because they areeasily reducedii. If there is a metal in a reaction, it is usually part of an ETCiii. The Fe2+/Fe3+ redox site is found in the cytoplasmic membrane, transporting electrons1. The metal cofactors are what hand electrons between componentsCytochromeHemeRedox site(Fe2+