BIOL 1107 1nd Edition Lecture 9 Outline of Last Lecture I Phospholipid Bilayer a Movement across membrane b Bend in tails II Concentration Outline of Current Lecture I Reduction Oxidation Reactions a NAD and NADH b Electronegativity II Cellular Respiration a Glycolysis Phosphorylation b Pyruvate c Citric Acid Cycle d Electron Transport Chemiosmosis Current Lecture I Reduction Oxidation Reactions Reduction Oxidation reactions redox reactions are chemical reactions that involve electron transfer and drive ATP formation during cellular respiration An atom molecule is reduced when it gains an electron the charge reduces An atom molecule is oxidized when in loses an electron o If an atom loses an electron another atom has to gain it Therefore reduction and oxidation are always coupled Electron donors are always paired with electron acceptors The reaction continues to take place until an atom can no longer receive an electron a NAD and NADH o NAD can t give electrons but it accepts them o HADH is an electron carrier which means it has to not only accept electrons becomes reduced but it also has to give them up oxidized o In electron transport NADH gives up hydrogen atoms Reduction NAD NADH Oxidation These 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 b Electronegativity o When you go from NAD to NADH a molecule picks up H if it has a higher electronegativity than the substrate you have encountered In order for NADH to give up an electron it has to be exposed to another molecule with a higher electronegativity Electrons continue to pass on to molecules with higher electronegativity s until the highest electronegativity is reached therefore stopping the reaction Oxygen is the final electron acceptor and receives hydrogen forming water Redox reactions use energy to make ATP II Cellular Respiration any suite of reactions that produces ATP in an electron transport chain Takes place in the mitochondria Has 4 steps 1 Glycolysis glucose is broken down to pyruvate A glycolysis reaction is a series of 10 chemical reactions The first 5 reactions are energy investment reactions bringing in ATP in order to get glycolysis stated Glucose is phosphorylated pushed to a more exited state then phosphorylated a second time which splits the glucose molecule into two The second series of reactions take phosphate and removes it making energy available to the system Makes ADP to ATP Substrate level phosphorylation removes phosphate from substrate and sticks it on an ADP molecule Oxidative phosphorylation uses oxygen as the final electron acceptor in order to provide enough energy to stick to ADP The gross number of ATP after glycolysis 4 ATP per glucose The net number of ATP after glycolysis 2 ATP have to account for the 2 ATP that was brought in to get the reaction started 2 Pyruvate Processing pyruvate is oxidized to form acetyl CoA 3 Citric Acid Cycle acetyl CoA is oxidized to CO2 4 Electron Transport Chemiosmosis compounds that were reduced in steps 13 are oxidized in reactions leading to ATP production Protein complexes are implanted onto the cell membrane Most H ions are stuffed in the inner cellular membrane while others are pumped through the membrane to create water H ions in inner cellular membrane create a concentration gradient causing proteins to flow back through the membrane banging into the turbine which starts spinning The rotational energy is then transformed to chemical energy
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