BIOL 1107 1nd EditionLecture 9Outline of Last Lecture I. Phospholipid Bilayera. Movement across membraneb. Bend in tailsII. Concentration Outline of Current Lecture I. Reduction-Oxidation Reactionsa. NAD+ and NADHb. ElectronegativityII. Cellular Respirationa. Glycolysis- Phosphorylation b. Pyruvatec. Citric Acid Cycled. Electron Transport & ChemiosmosisCurrent LectureI. 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 electrono If an atom loses an electron, another atom has to gain it! Therefore reductionand 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 electrona. NAD+ and NADHo NAD+ can’t give electrons but it accepts themo 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. 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. Reduction NAD+ NADHOxidationb. Electronegativityo 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 CoA3. Citric Acid Cycle acetyl CoA is oxidized to CO24. Electron Transport & Chemiosmosis compounds that were reduced in steps 1-3 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
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