Exam 4 Week 3 Notes
Exam 4 Week 3 Notes 3050
Popular in Essential Elements of Biochemistry
Popular in Biochemistry
This 7 page Class Notes was uploaded by Luke Holden on Sunday April 17, 2016. The Class Notes belongs to 3050 at Clemson University taught by Dr. Srikripa Chandrasekaran in Winter 2016. Since its upload, it has received 35 views. For similar materials see Essential Elements of Biochemistry in Biochemistry at Clemson University.
Reviews for Exam 4 Week 3 Notes
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 04/17/16
Exam 4 Week Notes 4/11/16 The Electron Transport Chain (ETC) Background knowledge required to understand ETC: o Redox Reactions: E’ –Standard Reduction Potential o, The more negative your E’ the more likely that your molecule will be oxidized The more positive your E’ the more likely that your molecule will be reduced Think of this whole thing like an electron tower. If the E’ is negative then you are standing at the top of the tower. When the molecule is oxidized, the electrons fall down the tower. The farther they fall (the greater the difference in E’ ) the more energy that is released. This is why oxygen is the terminal electron acceptor in the ETC because the electrons can fall the furthest. How the ETC is set up: Glycolysis NADH: 2 NADH Krebs NADH and FADH 8 NADH 2 FADH Some more about those complexes: o Complex 1 called NADH dehydrogenase o Complex 2 Called Succinate Dehydrogenase o Complex 3 cytochrome b/c complex o Complex 4cytochrome c oxidase Electron buses: o ubiqinone This bus carries the electrons from complex 1 and 2 and carries them to complex 3. o Cytochrome c carries the electrons from complex 3 to complex 4. 4 Important Biomolecules that make up the complexes: o Flavoproteins contain flavin (FAD)(FMN) o FeS proteinnonheme proteins contain 24 fe atoms bound to protein via cysteine residues o Cytochromes heme proteins contain single Fe atoms bound to the heme o Ubiquinone (Coenzyme Q) nonprotein Lipophillic molecule Slide 13 Explanation: o What Dr. Sri wants us to take out of this slide is that Complex 1 and 2 have more flavo proteins and FeS proteins o Whereas complexes 3 and 4 contain more cytochromes The ETC and Standard Reduction potential Explained: o When you start at complex 1 you are essentially starting at the top of the electron tower and then going down the tower. o As you go down the tower, you will increase in standard reduction potential. o Therefore, the highest standard reduction potential is oxygen Some poisions inhibit ETC o Amytal and Rotenone Inhibits the movement of electrons from NADH to complex 1 o Antimycin Inhibits the transfer of electrons in complex 3 o Carbon monoxide, Cyanide, and Azide inhibit the final transfer of electrons to oxygen 4/13/16 ATP synthesis o Loosely referred to as the phosphorylation of ATP o 3 types of phosphorylation Substrate level phosphorylationATP sythsis is coupled to carbon metabolism Oxidative phosphorylation ATP synthase coupled to oxidative processes of ETC PhotophosphorylationATP synthesis coupled to the light drive reacitons of photosynthesis o ETC When a complex is transferred electrons either via a electon bus or NADH or FADH2, protons are pumped across. This is extremely important to the function of making ATP from the ETC because the protons establish an electrical and chemical gradient This gradient is creates what is called proton motive force (PMF) This is generated in the intermembrane space. Also, complex 2 does not pump electrons The Math of ATP synthesis: o 2 NADH from glycolysis complex II o 8 NADH from Krebs complex I o 2FADH2 from Krebs complex II o Total protons put in the membrane space = 104 o ATP synthase requires 3 protons for one ATP to be made Plus 1 proton to shuttle a phosphate group across the membrane to be phosphorylated with ATP in the synthase (SHE WILL SPECCIFY WEATHER OR NOT TO USE THE FOURTH PROTON) o Therefore 104 protons 4 protons =26 ATP The electrochemical potential o Electrical potential refers to the charge difference o Chemical potential refers to concentration difference 4/15/16 Chemiosmotic theory o Chemical reactions could be coupled to osmotic gradients o Protons can only pass though ATP synthase to get back in o ATP synthesis is coupled to the shuttle of protons back into the matrix Evidence supporting the chemiosmotic theory o Active mitochondrion secrete protons o ATP is not made when inner membrane is disrupted o Molecules can lower ATP synthesis by collapsing the proton gradient Uncoupelershydrophobic compounds with a dissociable proton carry back across membrane Ionphores fake channels that are inserted into membrane that can shuttle the protons back across. o There is enough gradient to drive ATP synthesis. Examples of uncoupling: o Brown fat: This is found in hibernating animals, cold adapted animals and newborns. This is adipose tissue that is rich in mitochondrion Electron transport is uncoupled by the protein theromgenin This protein is activated by the fatty acids of the adipose cells o Dinitrophenol – toxic phenol; used as insecticide; human toxicity symptoms include marked fatigue, elevated body temperature, cyanosis. Gramicidin – antibiotic produced by Bacillus breva; used to treat local (topological) infections of gram+ bacteria. The ATP Synthase, A marvel of Biology Things to know about this bad boy: o It is driven by PMF o It makes ATP o β is the catalytic site (where the ATP is synthesized) o F 1 sticks into the matrix and spits out ATP by spinning and the β subunit changing conformation o F0 is grounded in the membrane o Takes 3 protons to turn it 360 = 1 ATP o WE DON’T HAVE TO KNOW THE FUNCTIONS OF ALL THE SUBUNITS, ONLY β. o o The How the whole changing the conformation thing works: o So the β subunit has three distinctive sites on the F1 complex. HOWEVER, THEY DON’T ROTATE AT ALL! o So the β subunit stays in one place and the γ subunit spins and causes the β subunit to change conformation. o The β subunit has three distinctive conformations. It has the tight, loose, and open. o In the open sight, the ADP and a phosphate are placed inside. Much like loading a gun o Then when the γ rotates, it will then turn into the loose conformation. Here, the subunit locks the ADP and phosphate group in place until the γ subunit rotates again. o Then the tight conformation is caused when the γ subunit rotates again. Here the ATP is made and then one final rotation with release the ATP and thus the cycle starts over again. o Wait, there is more o The ATP synthase needs some help making ATP and keeping its work area clean. o Phosphate Translocator: This uses one proton to reduce the charge on a free floating phosphate group to bring it in the membrane. o ADP/ATP Translocator: As ATP is being made, ADP is being brought into the matrix. Therefore, as you make one ATP and push it out, you will bring another one in. o So what about NADH from glycolysis: o The 2 NADH made from glycolysis needs to be carried across the membrane into the matrix. o It can be done by either: Glycerol3phosphate shuttle (brain & skeletal muscles) Don’t get the glycerol 3 phosphate and glyceraldehyde 3 phosphate on the exam! Malate/Aspartate shuttle (liver).
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'