What would be the expected result of a Lys residue being substituted with a Ser

What would be the expected result of a lys residue

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37.What would be the expected result of a Lys residue being substituted with a Ser residue in the BPG binding site of hemoglobin? A)BPG would bind tighter because of the loss of a positive charge.B)BPG would bind tighter because of the gain of a positive charge.C)BPG would bind less tightlybecause of the loss of a positive chargeD)BPG would bind less tightly because of the gain of a positive charge.E)This substitution would have no effect on the binding of BPG.Ans: C Section: 9.4 39.What does fMRI measure on the molecular level and what does this mean at the tissue level? 6
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Chapter 9 Hemoglobin: An Allosteric Protein amounts of deoxy- and oxyhemoglobin in the circulation of a specific organ 44. Draw the oxygen-binding curve of myoglobin and that of hemoglobin. Indicate the partial pressure of oxygen in the lungs and the range of pressure in tissue. Ans: Section: 9.1 46. Briefly describe cooperative binding. Ans: Cooperative binding occurs in multi-subunit proteins that possess multiple-binding sites. The binding of a ligand to one site causes a conformational change that influences the binding of the ligand to the next site. The binding sites are not independent, but each binding event affects the affinity of the next binding event. Section: 9.3 49. Describe the chemical basis of the Bohr effect. Ans: The effect observed by Christian Bohr is that hemoglobin becomes deoxygenated as the pH decreases. In deoxyhemoglobin, three amino acid residues form two salt bridges that stabilize the T state. One of these is formed between the C-terminal His β146 and an Asp residue (β94). As the pH increases, this stabilizing salt bridge is broken because His becomes deprotonated and loses its positive charge. At lower pH values, this His is positively charged. The formation of the salt bridge shifts the equilibrium from the R state to the T state, thus releasing oxygen. Section: 9.5 50. Describe how carbon dioxide affects the oxygenation of hemoglobin. Ans: Increased levels of CO 2 .cause hemoglobin to release oxygen. The more active the tissue, the more fuel is burned and the more CO 2 is produced. These active tissue cells have the greatest need for oxygen to produce more energy. The CO 2 combines with the N-terminal 7 Lungs 20 – 40 torr
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Chapter 9 Hemoglobin: An Allosteric Protein amino groups to form negatively charge carbamate groups. The negatively charge carbamate groups form salt bridges that stabilize the T state. Thus, the increase of carbon dioxide causes the conversion of the R state to the T state, releasing the bound oxygen to the tissues producing the most CO 2 . Section: 9.5 8
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  • Fall '17
  • Hemoglobin

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