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35 Cards in this Set
- Front
- Back
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what happens to NADH in H+ poor environments?
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NADH reoxidised to NAD at fastest possible rate - fuel oxidation is escalated
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uncouplers affect only certain cells, what is one exception to this rule?
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dinitrophenol
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what does brown adipose tisue do? where is it located? what happens to it over time?
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keeps body warm, has a very good blood supply, mainly located above kidneys, more abundant in babies and hibernating animals, lose it as get older
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besides making ATP, what else is the proton gradient used for?
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transporting phosphate into mitochondria
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in the electron transport chain, what does NADH donate its electrons to?
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complex 1
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what are prosthetic groups? what are some examples?
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things that carry hydrogens or electrons. eg metal ions Fe(2+ 3+), Cu
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which complexes in the electron transport chain contain prosthetic groups?
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complexes 1 and 3
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what happens to the electrons from NADH after they're delivered to complex 1?
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flow through prosthetic groups and protons are moved out of the matrix into the cytoplasm, electrons picked up by ubiquinone (UQ)
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what is another name for ubiquinone?
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coenzyme Q
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what does ubiquinone pick up from complex 1?
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electrons in the form of hydrogen to become UQH2
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between which complexes does UQ ferry H-?
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between complex 1 and 3. and between compex 2 and 3
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how many H+ are pumped out of complex 1?
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4
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how many H+s are pumped out of each complex in the electron transport chain?
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complex 1 = 4. complex 3 = 4. complex 4 = 2
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where do the electrons go after complex 3?
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are given (one by one) to cytochrome C (cyt C) and passed to complex 4
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what does complex 4 do with the electrons?
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reacts them with oxygen to get water (4H- and O2 = 2H20) then pumps out 2 H+s
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where are the proteins that make up the electron transport chain?
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inner mitochondrial membrane
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what are the complexes made of?
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many different proteins
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where does UQ live?
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it's very hydrophobic and lives its entire life in the inner mitochondrial membrane
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what is it that generates the proton gradient?
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movement of H- down the electron transport chain
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what is complex 2? can it pump H+s into the cytoplasm?
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Flavin Adenine Dinucleotide (FAD) - it doesn't have a face on the cytoplasm side so it can't pump any H+s out
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how does complex 4 work?
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complex 4 passes everything down until oxygen and protons take electrons and make water. in the process, 2 H+s are actively pumped out into cytoplasm
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where does NAD mainly take H-s from?
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alcohol groups, coverting them into carbonyl groups
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what is the structure of NAD?
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two nucleotides joined together
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what is niacin?
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the nicotinamide structure from NAD with H-
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what is the structure of UQ?
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very long hydrocarbon tail (hydrophobic - spends life in innermitochondrial membrane). has an aromatic ring with 2 carbonyl groups - can accept 2 hydrogens
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where does UQH2 shuttle hydrogens?
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to complex 3 (from complexes 1 and 2)
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what is cytochrome C?
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electron carrier - picks up electrons from complex 3 gives to complex 4
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how does cytochrome C carry electrons?
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has a metal ion at its core (Fe) to carry electrons. NB carries electrons, does NOT carry hydrogens (H-)
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what is FAD particularly good at taking Hs from?
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saturated hydrocarbon chain
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where does FAD exist?
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in complex 2. it's stuck there, can't get out and roam around like NAD
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what is rotenone? how does it work?
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an electron inhibitor at complex 1 of the electron transport chain (essentially creates a traffic jam - get build up of electrons before complex 1, no electrons after it) - stops whole chain, H+ pumping stops, everything downstream is oxidised
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what is an electron inhibitor?
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inhibits electrons passing through at a certain complex in the electron transport chain. creates a build up of e-s before it (upstream) everything upstream is reduced, everything downstream is oxidised.
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what does cyanide do?
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inhibits electrons at complex 4. whole chain stops, H+ pumping stops, everything upstream stays reduced
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what happens if you provide an alternative acceptor to a complex being inhibited?
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alternative acceptor accepts electrons from the complex before the blockage point and allows the electron transport to continue working provided there's a steady supply of alternative acceptor
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what is an example of an alternative acceptor?
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methylene blue
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