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46 Cards in this Set
- Front
- Back
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Respiration is energetically _______ favorable than fermentation. |
more |
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What catalyzes the transition step from glycolysis to krebs/tca? - complex of 3 enzymes that separately catalyze 3 reactions necessary for _________ ________ of ______ to ________ (which then enters krebs) - pyruvate dehydrogenase is inhibited when one or more of the 3 following ratios are increased: _______, ______ & _______ |
Pyruvate dehydrogenase oxidative decarboxylation of pyruvate to acetyl-CoA ATP/ADP NADH/NAD+ acetyl-CoA/CoA
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In respiring organism (instead of being fermented), ______ completely oxidized to ____ yielding ___ ATP OR GTP, ___ NADH & ___ FADH. - also source of many biosynthetic ________. This is the reason why most bacteria (even those not respiring) still run all/most of these reactions |
acetyl-CoA CO2 1 4 1 intermediates |
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Benefits of TCA as amphibolic pathway 1. as a catabolic pathway... - Much _______ energy yield than fermentation - The _____ intermediates (citrate, malate, fumarate, & succinate) are _____ natural plant and fermentation products and can be readily catabolized through the citric acid cycle alone. |
greater C4-C6 common |
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The citric acid cycle generates many key intermediates for _______ purposes: - ____________ & ___________ - _________ - __________ |
biosynthetic alpha-ketoglutarate and oxaloacetate Succinyl-CoA Acetyl-CoA |
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________ - can operate as adjunct to TCA - as an amphibolic cycle, catabolic and anabolic processes can become _________ - It's the major way in which the depleted 4C biosynthetic intermediates are ___________. - Avoids complete remineralization of carbon source (the 2 ________ steps are skipped) |
glyoxylate shunt unbalanced replenished decarboxylation
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Look over diagram - slide 7 lec 15 |
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Glyoxylate cycle/shunt - also allows organisms to utilize _____ as a major source of ______ and energy when glucose isn't available - Some ______ and ______ also converted into 3-C precursors (PEP & pyruvate) for glucose biosynthesis (gluconeogenesis). - Important for _______ of lung pathogens Pseudomonas aeruginosa and Myobacterium tuberculosis. |
lipids carbon malate OAA pathogenicity |
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Recycling of NADH & FADH2 via _____ is much more efficient than fermentation. |
Electron transport chain |
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Read over diagram on slide 9 (lec 15) |
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Only ____ ATP comes from SLP, the rest comes from oxidative phosphorylation. In total, there are ____ ATPs produced per glucose. - ATP is eventually produced at the expense of the __________, which is generated by electron transport (oxidative phosphorylation). |
4 38 proton motive force
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Electron transport systems - Present in __________ _________ of prokaryotes - Used to recycle ______ & _____ with higher ATP yield than fermentation - Involves sequence of ___________ reactions after which e's use to reduce an ______ e- acceptor. - energy released by electron transfer coupled to extrusion of _______ & generation of the _________. |
cytoplasmic membrane NADH & FADH2 oxidation-reduction external protons proton motive force |
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Read through diagram Slide 11 (Lec 15) |
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Membrane electron carriers are present in complexes. Name 5 e- carriers.
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NADH dehydrogenases flavoproteins Iron-Sulfur proteins Quinones Cytochromes |
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Electron Carriers NADH dehydrogenases: proteins bound to inside surface of cytoplasmic membrane; oxidizes ______ and passes _____ & ______ to ________ (part of same complex in mitochondrial ETCs) |
NADH electrons protons flavoprotein |
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Electron Carriers Flavoproteins: contains flavin prosthetic group (ex FMN, FAD) that accepts 2 electrons and 2 protons but donates ___________________ to the next protein in the chain ( _______ excluded). |
only the electrons protons |
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Electron Carriers Iron-Sulfur proteins: - contain cluster of iron and sulfur - metalloproteins - example: ferredoxin - reduction potentials vary depending on number and position of Fe & S atoms - carry _____ _______ |
electrons only |
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Electron Carriers Quinones: hydrophobic ________ molecules that participate in electron transport (ex: Coenzyme Q = ubiquinone) - accept ______ and ______ then donate only ______ while _____ _______ to exterior. - protons come from dissociation of water in cytoplasm, leaving hydroxide ion behind (contributes to charge separation across membrane). |
non-protein-containing electrons and protons electrons transferring protons |
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Electron Carriers Cytochromes: - Proteins that contain __________. - Accept and donate a __________ via the iron atom in heme - May exist in complexes that couple reaction to proton extrusion
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heme prosthetic groups single electron
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Electron carriers are arranged in order of what? So it goes from what to what? - Alternate electron-plus-proton and electron-only carriers - each carrier is ______ & then _______ (recycled) - energy released from redox reactions coupled to proton extrusion which generates the __________ - Some external e- acceptor is ultimately _______: - _________: aerobic respiration - anything else: __________
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- increasing reduction potential - goes from better electron donors to better electron acceptors - reduced & then reoxidized -proton motive force -reduced -oxygen -anaerobic respiration |
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Look over slide 17 (lec 15) |
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Comparison of mitochondrial-like and E.coli-type ETCs - __________ contain cytochrome c oxidase which is the basis for the diagnostic test. - In E. coli, alternate __________ used depending on growth conditions. |
- mitochondrial-like bacterial ETCs - cytochromes |
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Read over slide 18 (lec 15) |
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Oxidase Test - Most _______ _____ _______ possess cytochrome c oxidase. - Many facultative anaerobes (like E. coli) use distinct ______ _________ ________
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- obligate aerobic bacteria - distinct terminal cytochrome oxidases |
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Electron Transport Chain of E. coli - E. coli uses different cytochromes depending upon _________ _________. - _______ has higher affinity for oxygen but is less efficient than ______
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oxygen availabilty Cyt bd Cyt bo |
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Branched Pathway: Describe the differences between the bd branch and bo branch (in terms of what phases they're used and aeration)) |
bd branch - stationary phase, low aeration bo branch - log phase, high aeration |
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Look over diagram slide 20 (lec 15) |
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Generation of the proton motive force during aerobic respiration can take place in the exterior of the cytoplasmic membrane (_________) or in the mitochondrion. |
prokaryote |
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READ - Chemisomotic Hypothesis (Peter Mitchell): The theory suggests essentially that most ATP synthesis in respiring cells comes from the electrochemical gradient across the inner membranes of mitochondria by using the energy of NADH and FADH2 formed from the breaking down of energy-rich molecules such as glucose. |
:-) |
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The electron transport system pumps protons out of the cell. The resulting __________ gradient of protons (proton motive force) drives conversion of ADP to ATP through ATP synthase. - results in generation of ____ gradient as well - inside becomes electrically ______ & ______ - outside becomes electrically _____ & ______ |
electrochemical pH negative and alkaline positive and acidic |
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ATP synthase (ATPase) - Complex that converts _______ into _____ & contains ____ components. |
proton motive ATP 2 |
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Two components of ATP synthase: 1. F1: ________ extramembrane complex, faces ______ 2. F0: proton-conducting _______ channel |
multiprotein cytoplasm intramembrane
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This component of ATP synthase is a proton conducting intramembrane channel |
F0 |
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This component of ATP synthase is a multiprotein extramembrane complex that faces the cytoplasm |
F1 |
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ATP synthase is _________; dissipates proton motive force - functions like rotary engine (conformational changes) |
reversible |
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Read - processes powered by proton potential include ATP synthase, flagellar rotation, uptake of nutrients, and efflux of toxic drugs |
:-) |
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Anaerobic respiration Use of terminal electron acceptors other than ________. Ex: nitrate (NO3-), ferric iron, sulfate, carbonate, certain organic compounds (fumarate) - yields _______ energy because E0 of electron acceptor is ______ positive than E0 of O2. -Many prokaryotes are _______ - can switch components of ETC to use different oxidants. - still using electron transport to generate a proton motive force |
O2 less less facultative |
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- aerobic respiration resembles _________. - anerobic respiration uses a different ______ & can reduce NO3 to NO2 to NO to N2O to N2 is a process called __________ |
mitochondria cytochrome denitrification |
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Read over slide 26 (lec 15) |
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Sulfate reducing bacteria - Common in _______ _______ sediments rich in decaying ______ _________. - use sulfate as a terminal electron acceptor and produce H2S (rotton egg smell) - can react with metals to form FeS (dark color sludge) |
anaerobic aquatic organic matter |
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Look over diagram on slide 28 (lec 15) |
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Chemolithotrophy - Uses _________ as source of energy and electrons: e.g. hydrogen sulfide (H2S), hydrogen gas (H2), ferrous iron (Fe2+), ammonia (NH3) - typically ________ (uses ___ as terminal e- acceptor) - also uses electron transport & proton motive force to generate ATP - usually also ________ (fixes CO2 into organic carbon) |
inorganic chemicals aerobic oxygen autotrophic |
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Look over diagram on slide 29 (lec 15) |
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Read: Representative chemolithorophs - energy/e- sources often produced by "neighbors" as reduced end pdts of anaerobic respiration or fermentation - in turn electron acceptors are recycled |
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Major Groups of Chemolithotrophs _______ (hydrogen bacteria) - thermophilic bacteria, grows optimally around 85 C. _______: convert Fe2+ to Fe3+ ________: bacteria oxidize ammonia and nitrite to nitrate ________: use hydrogen sulfide (H2S), sulfur (S0), thiosulfate (S2O3 2-) |
hydrogenotrophs iron oxidizers nitrifiers sulfur oxidizing microbes |
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Winogradsky - an early environmental microbiologist who showed that the _____ requirement of Beggiatoa was an energy source; oxidized as we oxidize organics |
H2S (H2S --> S0 --> SO4 2-) |
