Exam 2- chapter 9 photosynthesis PDF

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photosynthesis chapter bio 101...

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Chapter 9- Photosynthesis Photosynthesis  Light energy  chemical energy  Light travels in packets of energy called photons  Certain molecules can absorb certain wavelengths= pigments  The light comes as white light Pigment- chlorophyll  When light of a particular wavelength hits it, it forces the electron to move to a higher energy level o When the electron goes back to its original energy level it can emit heat or light (florescence) o Energy of the electron can be transferred to another molecule (resonance transfer) o The electron itself can be transferred  Types of chlorophyll o Chlorophyll a- primary type in trying to convert the visible light into some form of chemical energy o Chlorophyll b- accessory pigment o Carotenoids- accessory pigments o Each of these have their own absorbency spectrum Chloroplast  There is an outer membrane  inter membrane system where there are thylakoids (membrane sack, or vesicle- has a membrane on the outside and the thylakoid lumen on the inside), stacks of thylakoid are granum 6CO2 + 12H2O  C6H12O6 + 6O2 + 6H2O Photosynthesis is stages  The products of one drive the second step 1. Light dependent- in thylakoids  12H2O + 2NADP + 18ADP + 18Pi  We want to produce 6O2 + 12NADH +18ATP  Pigments grouped as antenna complex- the pigments are located one right next to each other. Light hits a pigment and if it can’t do anything with the light it passes the light to the next pigment and it keeps going until it hits the reaction center pigment (specialized chlorophyll a molecule, specialized because of its location and the pigment molecules around it- it can now donate the high energy electron to a primary electron acceptor molecule) o Two types ( based on their absorption maximum)  Photosystem II  P680 light- light is indirectly involved, the electron splits the water molecule

 electron going down chain to produce NADPH  Non cyclic electron transport  Photosystem I  P700 light  Cylic electron transport  Produces ATP Generating ATP- based on chemiosmosis  Through electron transport- between thylakoid and lumen  Plasto chrinom sends the electron to the cytochrome o Then the electron are donated to plasto cyanine o Then taken to photosystem I  Feradoxin sitting outside of photosystem I and it takes the electron and sends it to NADP feradoxin reductase o Then is donated to NADP + proton  Increasing the number of protons in the lumen, in the stroma the protons are being used to reduce NADH  Non cylic cycle is used to pump protons from the stroma into the lumen, and make a proton gradient o There is ATP synthase in order to allow protons through because the membrane won’t let them through 2. Carbon fixations- in stroma  Take NADPH + 18ATP + 6CO2  C6H12O6 + 12NADP + ADP + Pi (inorganic phosphate) + 6H2O  Fix carbon into RuBP (a 5 carbon compound), will react with CO2 and produce 2 3carbon compounds (PGA)  RuBP carboxylase/ oxigonase- extrememly important enzyme o It catalyses a reaction  In bundle sheath cell C3 plants work...