BIOL 120 1st Edition Lecture 14Outline of Last LectureI. Electron Transport ChainII. Anaerobic vs. AerobicIII. Photosynthesis OverviewOutline of Current LectureI. Photosystems II. Non cyclic III. Cyclic IV. Calvin CycleV. Photorespiration Current LectureI. PhotosystemsA. Photosystem: a complex formed from chlorophyll molecules working together in groups B. Has two major elements along with proteins that capture and process electrons: 1. Antenna complexa). also known as light- harvesting complex b). captures photons and channels them to reaction center chlorophylls c). In chloroplast these are a web of chlorophyll molecules held together in the thylakoid membrane by a matrix of proteinsThese 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.2. Reaction center a). This is the transmembrane protein- pigment complexb). when a chlorophyll absorbs a photon of light an electron is excited to ahigher energy levelC. Photosystem II1. Has a core of ten transmembrane protein subunits 2. Has two P680 chlorophyll3. Reaction center contains 4 manganese atoms (needed for oxidation of water)4. Has b6-f complex  Proton pump embedded in thylakoid membraneD. Photosystem I1. reaction center has 12-14 protein subunits 2. Has two P700 chlorophyll 3. accepts electrons to make NADP into NADPH E. Chemiosmosis1. used to synthesis ATP2. Chrlroplast has ATP synthase enzymes in the thylakoid membrane that allows protons back into the stroma a). the stroma has enzymes that catalyze the reaction of carbon fixation (Calvin Cycle)II. Non Cyclic A. also known as Z pathways B. source of electrons is from photolysis of water C. Generates NADPH, oxygen and ATPD. Has 4 steps1. Primary photoevent a). photon of light is captured by a pigment molecule2. Charge separationa). energy is transferred to the reaction center and an excited electron goes to an acceptor3. Electron Transporta). electrons move through carriers and reduce NADP to NADPH4. Chemiossmosis a). Makes ATP E. Require two connected photosystems1. uses both photosystem I and II 2. Photosystem II (P680)  pool of electrons coming from the photolysis of watera). Energy level of protons goes up and then transferred to electron acceptor because it is too much and keeps being transferred until I (energy slowly decreasing until reaches I and process continues)III. Cyclic A. only uses Photosystem IIB. Generates ATP through the electron transport (anoxygenic  doesn’t make oxygen)IV. Calvin Cycle A. also called C3 pathways of photosynthesis B. Key step is attachment of CO2 to RuBP to form PGA C. Uses rubisco to react with carbon and oxygen a). carboxylase  fixing carbonb). oxygenase  fixing oxygen c). inefficient because it catalyzes both carbon and oxygen D. Light reaction provides ATP to run the Calvin Cycle which makes glucose, fixes CO2 and regenerates RuBPE. Three Phases:a). Carbon fixation  RuBP (5C) + CO2  PGA (3C)b). Reduction  PGA is reduced to G3P which is used to synthesis glucose (not a direct product of Calvin Cycle)i). extra sugar created is stored as starch c). Regeration of RuBPV. PhotorespirationA. Carboxylation (carboxylase)  favored under normal conditionsB. Photorespiration (oxygenase)  favored when stoma are closed in hot conditions C. Stomata1. openings in leaves that control gas exchange (2 guard cells)2. CO2 concentration is low during photosynthesis  let CO2 in a). needed because the Calvin Cycle is constantly using up