If the subunits of Hb didn’tcommunicate with each otherA) the binding curve of Hb tooxygen would be sigmoid-shaped.B) Hb would bind oxygen moretightly.C) the binding curve of Hb tooxygen would be hyperbolic.D) Hb would bind oxygen moreweakly.Fig. 5-4LehnFig. 5-12LehnFig. 5-11LehnFig. 5-10LehnFig. 5-10LehnFig. 5-10LehnFig. 5-16LehnFig. 5-9LehnFig. 5-18aLehnAllosteric Modulation: BPG• 2,3-bis-phosphoglycerate(BPG) binds Hb and decreasesthe binding affinity for oxygen• BPG’s negative groups formhydrogen bonds and saltbridges in the central subunitinterface of Hb and stabilizedeoxy (‘T’)• Binding site distinct fromheme site — allosteric• But influences affinity ofheme siteFig. 5-18bLehnFig. 5-18cLehnFig. 5-17LehnWhich one of these statementsabout Hb is true?A) The T-state is stabilized by lowpH.B) The R-state releases oxygen.C) BPG binds weakly to adulthemoglobin.D) High [H+] stabilizes the R state.E) All of the options above arefalse.Fig. 3-13B and TFig. 5-20 LehnFig. 5-20LehnFig. 3-14B and TFig. 5-20LehnHbS: α2β2 E6VSickle Cell (HbS)• Fiber —RBC adoptssickle shape• Polymerization onlyoccurs in the deoxy (T)form — sickling occursin capillaries• Sickle cells do notdeform easily intransport throughcapillaries and ruptureeasily — microvascularvasoocclusion andhemolytic anemia• HbS — increasedresistance againstmalariaFig. 5-19aLehnFig.
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