UB BIO 201 - exam 2 notes (40 pages)

Previewing pages 1, 2, 3, 19, 20, 38, 39, 40 of 40 page document View the full content.
View Full Document

exam 2 notes



Previewing pages 1, 2, 3, 19, 20, 38, 39, 40 of actual document.

View the full content.
View Full Document
View Full Document

exam 2 notes

192 views


Pages:
40
School:
University at Buffalo, The State University of New York
Course:
Bio 201 - Cell Biology
Unformatted text preview:

lecture 12 02 13 2012 Light reactions Convert light energy into chemical energy stored in NADPH and ATP Water is the initial e donor to the electron transport chain water gets oxidized to O2 Dark reactions The NADPH and ATP from light reaction used to make carbs from CO2 Pathway for electron transport in chloroplast thylakoid Travels from photosystem 2 to 1 H2O PSII PQ lipid ctyb6 f PC peripheral protein PSI NADP H NADPH H2O is split in lumen to generate H in the lumen o Lumen is acidified Product is NADPH and proton gradient Stages of e flow in photosynthesis 1 Photolysis PSII using energy from light to split water 3 products o H2O H for H gradient O2 for mitochondria e for e transport 2 Pass e from PSII to PSI energy generated increases H in the lumen 3 Pass e from PSI to NADP produces NADPH electron from water is used to start this process not from the sun o sunlight is used to lyse break H2O The Z scheme for e transport in thylakoid High reduction potential low reduction potential back and forth Cannot go from high to low to pass eHave to lower reduction potential in order to pass eo Light does this P680 part of PSII P700 is part of PSI 1 Light provides the energy to split water and to lower the Eo value of P680 to excited state 2 The excited state of P680 now is low enough to pass e to PQ but now the Eo of P700 is too high to pass e further light energy at PSI is needed to lower the Eo of P700 so it can continue to pass e to NADP to make NADPH Summary of Light reactions 1 PSII P680 uses light energy to split water by photolysis H2O H O2 eo the H contributes to the H gradient in the lumen o the e are passed to the e transport chain and provides energy or more H pumping 2 Electrons passed to PQ and H go to lumen to increase H in lumen 3 Cytb6 f complex accepts e and pumps more H into the lumen 4 E passed to PC and PSI P700 5 E passed to NADP to make NADPH 6 Energy from H gradient is used to ATP in the stroma plants need water light and CO2 to grow o light to split water for energy Mitochondria and chloroplast e transport Mitochondria get proton gradient Chloroplast get proton gradient NADPH lecture 13 Some inhibitors of photosynthesis 02 13 2012 1 DCMU blocks e transport from PSII to PQ o steals electron o it is an artificial electron acceptor 2 Altrazine herbicide blocks e transport from PSII to PQ 3 DCIP artificial e acceptor that steals e from PQ 4 Paraquat herbicide steals e from PSI so that NADP doesn t get reduced to NADPH The CF1 CF0 can make ATP in vitro artificially 1 Put thylakoids in pH 4 CF1 faces outside lower H inside o pmf is inward 2 Wait until pH is 4 on inside load up H inside o pH 4 high H inside 3 Move thylakoids to pH 7 and add ADP Pi o high H in and low H outside pmf is outward now H gradient provides energy for ATP synthesis e transport is not needed for ATP synthesis in vitro How do thylakoid membranes harvest light to make NADPH and ATP 5 results of light shining on pigment o 1 Emitted as heat o 2 Emitted as fluorescence absorb as short wavelength and released as longer wavelength low energy o 3 Transmitted not absorbed goes straight through no change in wavelength o 4 Passed along to another energy carrier o 5 Reflected o not 100 harvesting of light chlorophyll are fluorescent but chloroplast are not pigment in thylakoid will pass the energy to e transport and not emitted o as chloroplast becomes fluorescent dying because it has no one to pass the energy to Absorption spectrum Less light transmitted more light absorbed Chlorophyll a very short wavelength best absorption Chlorophyll b short wavelength best absorption B carotene not orange best absorption High energy low wavelength Green light on green plant death o Because all the light will be reflected no light absorption Chlorophyll Pigment is amphipathic hydrophobic tail hydrophilic head lecture 14 02 13 2012 Protein analysis Electrophoresis movement of fully charged ionic compounds through a viscous medium by an electric field o Opposite charges attract each other o Anode positive pole Cathode negative pole o Anion anode Cation cathode o Used to separate purify and identify RNA and DNA 2 main types of gel electrophoresis o 1 native gel no detergents added most like in vivo rate of movement migration is affected by the native conformation shape size solubility and charge pH can affect migration o 2 Detergent usually SDS gels detergent gets rid of the shape everything is soluble Assume migration is only affected by size How to look at membrane proteins by SDS PAGE 1 SDS sodium dodecyl sulfate anionic detergent at most pH used 2 Separates proteins by their size o small proteins move through gel faster o assume that all proteins are denatured uniformly negatively charge soluble in presence of SDS o with no detergent present proteins could have a net charge of positive negative or zero and be in their native conformation depending on their pH Identification and separation of membrane proteins by SDS PAGE 1 SDS is an anionic detergent that solubilizes and coats all proteins with a negative charge 2 PAGE polyacrylamide gel electrophoresis 3 In presence of SDS all proteins migrate to anode positive pole 4 In SDS PAGE protein of same size move together in a band o Large proteins move slower top of the gel farther from the anode o Small proteins move faster bottom of the gel closer to the anode 5 Protein bands are stained to be seen and identified by co migration with known standards MW size is expressed as daltons Da 1000Da 1000MW lecture 15 02 13 2012 How to get a membrane protein out of the membrane and solubilized in water add ionic detergent like SDS RBC ghosts just plasma membranes Made by hemolysis Hypotonic lysis cells pop and reseal after osmotic shock General features of cytoskeletal components 1 Assembled from a pool of protein subunits o subunits polymerization polymers 2 Some polymers filaments are dynamic always changing by assembly and disassembly easy to change 3 main kinds of cytoskeletal filaments 1 Microtubules MT biggest o tubulin subunits are dimers joining of 2 alpha and beta tubulin form tubulin heterodimer o use GTP o made in the end growing end polarity o in all eukaryotes o function support intracellular transport 2 Intermediate filaments IF intermediate o made of polymers of intermediate filaments o made internal non polar o in all animals o function support structure 3 Microfilaments MF smallest o made of actin filaments actin monomers polymerization Filament polymer double


View Full Document

Access the best Study Guides, Lecture Notes and Practice Exams

Loading Unlocking...
Login

Join to view exam 2 notes and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view exam 2 notes and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?