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16 Cards in this Set
- Front
- Back
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What is BPG
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2,3 bisphosphoglycerate
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Le Chatelier's principle
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a system at equilibrium reacts to a change by adjusting so that equilibrium is maintained (equation shifts left or right)
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lack of BPG ___(increases?/reduces?)__ Hb P50 from _______ to _____
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reduces; 26 torr to 1 torr (in fetus)
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Why is BPG an allosteric effector?
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It binds at a separate site that O2 but affects Hbs affinity for O2. Hb may bind only one or the other
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BPG structure and properties
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-4-5 neg charges (at phys pH)
-synthed and degraded in RBCs (by glycolysis side rxn) - |
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What form of Hb does BPG bind to
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T form
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How many BPG sites are there per Hbt? per Hbr?
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1; essentially none, because site is distorted
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Where is the BPG binding site located on a Hb?
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parts of the 2 beta chains (on Hbt only). N-terminals of alpha-NH3 groups
-3 basic side chains |
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What is the relationship of fetal Hb (HbF) to adult Hb (HbA)
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the p50 of HbF is always lower :. O2 is always transfered to fetus
-HbF has lower BPG affinity due to fewer cationic groups |
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Structurally what is different btw HbF and HbA
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HbA--> alpha2beta2
HbF--> alph2gamma2 (?) |
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Does pH affect Mb's affinity for O2? Hb's? If so how
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Mb no effect. For Hb, direct relationship. Lowering pH increases p50 (decrease in affinity)
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Why is it important for __(Mb/Hb?)__ to be effected by pH?
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Hb. Because then it can dump O2 in exercising muscle (b/c metabolism increases [H+])
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What effect does CO2 have on O2 binding
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Inhibitory. Promotes dumping of O2 in places with high CO2 levels, aiding delivery.
-HbT reacts more readily with Co2 than HbR does |
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What is the danger of CO
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binds more tightly to Hb/Mb than O2 does. Toxic pollutand and metabolic end-product.
Dissociation is slow and catalyzed by light |
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HbT: summary
(3: molecs binding, features, and surrounding conditions) |
-binds H+, CO2 and BPG
-Contains 8 salt links (which break on oxygenation) -favored by high temp |
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HbR summary (2)
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binds 02 and CO, less intersubunit interactions
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