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19 Cards in this Set
- Front
- Back
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What characteristics of NADH allow it to be a regulator or cell functions? Why can't FADH2 do this?
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NAD binds to dehydrogenase, accepts an electron and diffuses away. It is the diffusion of NADH that allows it to be a regulator. FAD/FADH2 on the other hand is very reactive and might loose an electron to water. It must be covalently bound to its enzyme.
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What are electron carriers when electrons are transferred from NADH to oxygen?
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Protein prosthetic groups: flavins, iron sulfur clusters, hemes, and copper.
Free carriers: ubiquinone and cytochrome C |
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What happens in complex 1?
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The oxidation of NADH by coenzyme Q reductase.
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What happens in complex 2?
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electrons from succinate are passed to CoQ reductase
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Where do the electrons from complex 1&2 end up?
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CoQ then to complex 3
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What functions to shuttle electrons between complex 3 and 4? what is the active group?
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cytochrome c contains a heme prosthetic group
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Why does the electron transport chain only move one way?
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Each substrate has a high reduction potential than the substrate before it. This means that each substrate has a high electron affinity than its predecessor. Oxygen has the highest affinity.
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What is the proposed hypothesis that couples oxidative phosphoryation and electron transport?
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chemiosmotic hypothesis. Every time that an electron passes through complex 1-4 it produces hydrogen in the intermembrane space in the mitochondria. This high H+ concentration generates the high potential needed to drive the proton pump in complex 5.
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What compounds inhibit the electron transport chain? At what stage?
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amytal & rotenone-complex 1
antimycin A-complex 3 cyanide, CO, sodium azide- complex 4 oligomycin- binds the F0 domain of complex 5 and inhibits the reentry of protons into the mitochondrial matrix DNP-readily diffuses through the membrane and causes the loss of the proton gradient. The e- tx chain proceeds at full pace but no proton gradient develops. |
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What does ADP do to the proton gradient of complex 5
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Opens the proton gradient
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Where does oligomycin inhibit ATP synthesis?
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it stops protons from going through F0 of complex 5.
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Where does amyal and rotenone inhibit ATP sythesis?
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complex 1
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Where does antimycin A inhibit ATP production?
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complex 3
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Where do CN-, CO, and sodium azide inhibit ATP synthesis?
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Complex 4
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How does DNP inhibit ATP synthesis?
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It uncouples the electron transport chain from ATP synthesis. It embeds itself in the membrane and destroys the proton gradient.
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What are some cellular defenses against ROS?
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anti-oxidant enzymes: superoxide dismutase, catalase, and glutathione peroxidase
and vitamins E,C and possibly carotenoids. |
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What happens if there is no ADP?
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No ore oxygen consumption because there is no proton motion through complex 5 and a proton buildup so ETC no longer works
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What does oligomycin do to the rate of oxygen consumption by the cell.
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It stops it.
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What does DNP do to the rate of oxygen consumption of the cell?
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rapid oxygen consumption without ATP added.
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