BIO 326R 1st Edition Lecture 8 Outline of Last Lecture I. Sources of energy in the cella. ATP and transmembrane ion gradients (proton motive foce)II. Electron source in the cella. Oxidative reactionsi. Coenzymes like NAD+ hold e- (NADH)III. How do bacteria make ATPa. Proton motive forceb. Substrate level phosphorylation (fermentation)i. Convert ADP to ATP with 4 stepsIV. Glycolysisa. Uses same 4 stepsV. FermentationVI. RespirationOutline of Current Lecture I. Fermentation vs. RespirationII. Anaerobic Growth and Aerobic GrowthIII. Respirationa. Establishes pmfThese 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. F0F1 ATPaseIV. Pmfa. Synthesize ATP and transportb. Respirators vs. fermenters use of pmfCurrent LectureFermentation- We would normally respire, but if oxygen is low or unavailable, we ferment lactic acid- Uses substrate level phosphorylation and proton motive force but not the electron transport chain of pmfRespiration- Electrons are ultimately added to a terminal electron acceptoro Oxygen, nitrate, or sulfate Oxygen used in aerobic respiration Nitrate and sulfate used in anaerobic respirationAerobic and Anaerobic- Whether oxygen is around or not:o Aerobic growth and aerobic growth can respire or ferment Common misunderstanding that each can only do one or the other Aerobic- will respire (using oxygen), and if oxygen levels are low will ferment Anaerobic- will respire (using nitrate or sulfate) or fermentProton Motive Force- Used to:o Synthesize ATP Respiration- Enzyme converts NADH NAD and the proton leaves the cell to create a high concentration of H+ outside the cell, thus establishing a gradient so that work can be done and ATP can be synthesized- F0F1 ATPase= required enzyme that synthesizes ATP using the pmf as energy- 3-4 protons can make 1 ATPo Transport important molecules into the cell Respirators can create a proton gradient (with F0F1 ATPase) that allows protons to freely move back into the cell, down their gradient, via a transport protein. The transport protein then has an increased affinity for glucose, thus allowing glucose to move into the cell, against its gradient Fermenters can also use F0F1 ATPase, but to send protons out (opposite of respiration) and ATP is broken down to ADP + an inorganic phosphate- In a low pH, no need to do this because the gradient is already established so work can already be done- Saves energy by fermenting in a low pH environmento Motility Turn flagella for motilityo Maintain pH Sending protons in/out of the cellWhy respire?- Aerobic respiration gives ~30 ATP-- 2 from substrate level phosphorylation and 28 from pmf respiration- NAD+/NADH ratioo Respiring cell= 5-10o Fermenting cell=
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