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15 Cards in this Set
- Front
- Back
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What is ATP synthase? |
Molecular motor, consists of F0 and F1, F0 is transmembrane protein and forms a wheel, F1 is a rod with one end fixed to the hub of the wheel while the other is surrounded by a/B subunits, protons passing down the concentration gradient cause rod to rotate with the stationary bundle, Rotation provides mechanical energy necessary to catalyze endergonic combination of ADP and Pi |
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What is molecular bearing? |
One proton passing through F0 causing F1 to rotate by 180 degrees, synthesis of one ATp molecule requires 3 protons to turn rod 360 degrees, Contacting surfaces of rod and wheel lack polar and ionogenic groups, contain predominantly hydrophobic residues that lubricate breaking |
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What are the mechanisms of ATP synthesis? |
There are three identical a/B interfaces that can adopt three different conformations: Open conformations O (doesn't bind ligands), Catalytically inactive conformation L (binds ligands loosely), Catalytically active conformation T (loosely binds)
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What are the three steps involved in ATp synthesis ? |
ADP to Pi bind to L site, Conformational transitions...L to T, T to O and O to L, ATP is then synthesized at the T site and is released at the O site |
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Uncoupling electron transport and oxidative phosphorylation? |
electron transport and oxidative phosphorylation are tightly coupled, coupling depends on permeability of inner mitochondrial membrane, in resting state ATP requirement is minimal, ATP synthase is major pathway for protons to return to matrix, ATP inhibits ATP synthase and hence the path for protons to return to matrix and an increased gradient blocks electron transport |
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Action for 2-4-dinitrophenol |
carries protons across the inner membrane, this discharges the proton gradient and stimulates the etc without synthesizing ATP |
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What is brown adipose tissue and its function? |
Brown Adipose Tissue has the function to generate heat. It is brown because of the cytochromes. The inner membrane contains thermogenin, a proton channel that uncouples ETC and oxidative phosphorylation |
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What activates thermogenin? |
It is activated by f.a. and a high proton gradient, and blocked by ATP,ADP,GTP and GDP, hormones regulate heat production in BAT |
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Explain Control of oxidative phosphorylation. |
The adult needs 7000 kj of metabolic energy a day, this requires hydrolysis of 200 ATP molecules, ATP consumption varies depending on body activity, when [ATP] increases so does oxygen, amount of ATP in body is permanent at less than 0.1 mM |
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[ATP]/[ADP][P] controls rates of what? |
oxidative phosphorylation, electron transport, CAC, pyruvate oxidation and glycolysis |
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Increased ratio of [NADH]/[NAD] does what |
inhibits pyruvate dehydrogenase as well as several CAC enzymes |
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What is efficiency of aerobic/anaerobic metabolism? |
using same amount of nutrients, Anaerobic forms 2 ATP while Aerobic forms 38 ATP making Aerobic 19 times more efficient |
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What is cytochrome p450 and its function? |
availability of oxygen provides aerobic organisms with a mechanism for detoxification, lipophilic toxins accumulate in cells, P450 catalyzes RH + O2+ NADPH+ H>ROH + H2O + NADP+, water soluble toxins can be excreted from the cell |
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Heart attack and strokes |
lack of oxygen to heart and brain, lack of oxygen leads to use of glycogen supply and phosphocreatine for ATP and once that runs out, [ATP] decreases, ion concentrations are not maintained , osmotic balance is damaged, cell absorbs water, membranes swell and become permeable to macromolecules, cell content leaks and cell dies |
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Antioxidants and their function |
antioxidants destroy free radicals, preventing the creation of new radicals preventing illnesses such as parkinsons and alzheimers, Superoxide dimutase catalyzes: 2O2- RAD+ 2H+-> O2 and H2O2, catalase then converts H2O2 -> 2O2 + H2O, glutathione peroxidase uses tripeptide glutathione to catalyse a reaction that converts H2O2 to H2O. Vitamin E and C are also antioxidants |
