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77 Cards in this Set
- Front
- Back
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What is oxidative phosphorylation?
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Making ATP energy from the protonmotive force.
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The protonmotive force works as...
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an electrochemical gradient.
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Describe the conditions in the periplasmic space.
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Acidic and Positively Charged
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Why is the electrochemical gradient a source of potential energy?
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H+ cannot diffuse through the membrane.
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Who won the Nobel Praice for oxidative phosphorylation chemiosmosis work?
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Peter Mitchell
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What does allow the protons into the cell?
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ATP synthase and transmembrane proteins.
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What two things does ATP synthase do?
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Uses energy from H+ moving down electrochemical gradient and phosphorylates ADP.
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What is the electron transport chain?
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A series of electron carriers in the cell memebrane.
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What does the electron transport chain do?
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Oxidizes coenzymes.
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What is the first carrier in the electron transport chain?
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NADH dehydrogenase.
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What happens to NADH and the first carrier in the electron transport chain?
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NADH is oxidized to NAD+ and the first carrier is reduced.
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What does NADH dehydrogenase do?
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Reduces the next carrier.
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What is the second carrier?
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Flavin mononucleotide.
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What else does NADH dehydrogenase do?
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pumps H+ into the periplasmic space.
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What happens to the electrons?
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They pass through the electron transport chain.
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What is the final electron acceptor?
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Oxygen.
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What happens to the H+ after re-entering the cell?
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It binds with the final electron acceptor (fea), oxygen to form water.
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What are often the final electron carriers in the electron transport chain?
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Cytochromes
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If cytochrome C is present, what happens?
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Cytochrome oxidase catalyzes cytochrome C oxidation and oxygen reduction.
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What does the oxidase test for?
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Cytochrome oxidase
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Why is the oxidase test useful?
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It differentiates between Gram - rods
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If oxidase test is positive what are you dealing with? Negative?
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+ = Campylobactor (which causes food poisoning) and Pseudomonas.
- = Enterics. |
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Where do electrons come from for the electron transport chain?
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Catabolism
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What is catabolism?
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Break down of molecules to generate reducing energy.
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What four forms of producing energy are we comparing?
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Aerobic/anaerobic respiration, fermentation, and chemoautotrophy.
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What is aerobic respiration?
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The catabolism of polysaccharides and monosaccharides, proteins and lipids.
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What is the final electron acceptor of Aerobic respiration?
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Oxygen.
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What is the equation for the Aerobic respiration of glucose?
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C6H12O6 + 6O2 + 38ADP + 38PO4 --> 6CO2 + 6H2O + 38ATP
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What are the four steps of Aerobic Resipiration of Glucose?
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Glycolysis, Transition step, [TCA cycle, Kreb Cycle, and Citric Acid cycle], and the electron transport chain.
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What happens in Glycolysis?
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glucose is oxidized to pyruvate.
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What are the products of Gylcolysis and where does each come from?
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2 ATP (2 used, 4 produced) during substrate level phosphorylation, NADH during the electron transport chain, and 2 pyruvates from each one glucose
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What are the four steps of Aerobic Resipiration of Glucose?
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Glycolysis, Transition step, [TCA cycle, Kreb Cycle, and Citric Acid cycle], and the electron transport chain.
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What occurs during the transition step of aerobic respiration?
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Pyruvic acid is oxidized to acetyl CoA.
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What does CoA stand for?
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Coenzyme A
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What are the products of the transition step and where do that come from?
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NADH from the electron transport chain and acetyl CoA from the Kreb Cycle.
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How many times does the TCA cycle repeat per one glucose?
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twice.
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What are the products of the TCA cycle and where do they come from?
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CO2, 2 ATP (one/turn of cycle)...GTP (guanosine triphosphate), and NADH and FADH2 (reducing energy) from the electron trasport chain
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What is the first step of fermentation?
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Glycolysis.
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What is the second step of fermentation?
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Oxidation of the NADH from glycolysis.
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What is the final electron/H+ acceptor in fermentation?
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Pyruvate or pyruvate derivative.
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How much energy is generated in fermentation as compared to Aerobic respiration?
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Less.
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Where does ATP formation occur in fermentation and in what amounts?
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Substrate level phosphorylation and in small amounts.
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How much oxygen is used during fermentation?
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Oxygen is not used, but maybe be present.
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What are the end products of fermentation?
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Gases, acids, and neutral products.
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What does the combination of products depend on?
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The fermentation pathway.
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What accounts for the energy difference between fermentation and aerobic respiration?
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Fermentation does not have the electron transport chain or the Kreb Cycle.
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What does the fermentation pathway of a microorganism during fermentation depend on?
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The type of microorganism.
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How do we detect carbohydrate fermentation?
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pH indicators, Durham tubes, Ex. Phenol-red lactose/glucose medium
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When detected carbohydrate fermentation, what would yellow mean?
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Acidic and that fermentation occurred.
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Name four fermentation pathways.
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Lactic Acid, Ethanolic, Mixed-Acid, and Butanediol fermentation.
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When does lactic acid fermentation occur?
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When muscles run out of oxygen.
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The end products of Lactic Acid fermentation are either:
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homolactic or heterolactic.
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What do homolactic and heterolactic mean?
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only lactic acid, and lactic acid + CO2, and EtOH respectively.
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Give examples of lactic acid fermentors:
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Streptococcus (dental cavities), Leuconostoc (Sauerkraut), Lactobacillus (normal human gut flora...digestion).
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What are the end products of Ethanolic fermentation?
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CO2 and EtOH
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Give an example of an Ethanolic fermentor.
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Saccaromyces cerevisiae (brewers and bakers yeast).
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Is yeast a pro or eukaryote.
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fungi...eukaryote
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What are the end products of Mixed-Acid fermentation?
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ethanol, CO2, and H2, and then acetic, succinic, formic, and/or lactic acids.
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What test can be used to distinguish Mixed-Acid fermentation?
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Methyl Red Test (MR)
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What will the results of an methyl red test look like?
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Because methyl red is a pH indicator, basic = yellow and acid = red (different from usual).
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What two species can the methyl red test distinguish between?
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E. coli (MR+) and Enterobacter aerogenes (MR-)
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What are the end products of Butanediol fermentation?
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Butanediol and CO2
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What test can be used to determine Butanediol fermentation?
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Voges-Proskauer test (VP test)
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What is the problem faced by the Voges-Proskauer test? The solution?
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Butanediol is neutral, so it tests rather for acetoin, a butanediol precursor.
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Between what two microorganisms does the Voges-Proskauer test distinguish?
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E. coli (VP-) and Enterobacter aerogenes (VP+).
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Enterobacter aerogens and E. coli are quite similar and live in a common environment, why would we want to distinguish between them?
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E. coli is a fecal coliform, a fecal pollution indicator in the environment that is the pathogenic Enteric that lives the longest outside the gut where as Enterobacter aerogenes is non-pathogenic and nothing to worry about.
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What is the final electron acceptor of anaerobic respiration?
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Something other than oxygen.
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What are 3 differences between anaerobic and aerobic respiration?
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different carriers in electron transport chain, more ATP produced in aerobic, the final electron acceptor is different.
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What type of reaction is anaerobic respiration?
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A reduction.
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What type of reduction is anaerobic respiration?
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Nitrate or sulfate reduction.
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Demonstrate a sulfate reduction.
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SO4 --> H2S
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What are the characteristics of the Sulfate Reduction products?
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Anoxic sediments that smell bad and are a black color.
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Demonstrate the denitrification reaction.
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NO3-->N2 (gas)
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What is the source of most atmospheric Nitrogen?
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Denirification of bacteria.
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What is the nitrogen cycle?
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N2 <--> nitrogen fixation by bacteria <--> NH4+ <--> NO2- <--> Nitrification by bacteria <--> NO3- (plants like this) <--> denitrification of bacteria <--> N2
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Show the reaction of Methanogenesis.
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acetate --> CH4 (a green house gas...absorbs heat).
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What type of organisms undergo mathanogenesis?
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Methanogens such as Archaea which are obligate anaerobes.
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