With the use of site-directed mutagenesis, hemoglobin has been prepared in which the proximal histidine residues in both alpha and the beta subunits have been replaced by glycine. The imidazole ring from the histidine residue can be replaced by adding free imidazole in solution. Would you expect this modified Hb with free imidazole to exhibit oxygen binding? Why or why not?

The modified hemoglobin with free imidazole cannot be expected to show cooperativity in oxygen binding. The movement of iron ion takes place up in the plane of heme when binding of one subunit of hemoglobin takes place with oxygen. One of the iron's and oxygen's axial ligands comprise the proximal histidine's imidazole ring.  

With the movement of iron into the hemoglobin ring, the pulling of proximal histidine takes place along with it. Therefore, when binding of oxygen takes place with one subunit, a modification also takes place in the intersubunit associations, this also comprises displacement of the alpha helix. This phenomenon plays an essential role in modifying the hemoglobin's tensed state to the relaxed state. The withdrawal or mutation of the imidazole ring from the histidine residue does not further permit the cooperative binding as it is not associated physically with the alpha-helix.  

hypoxemia refers to a below usual concentration of oxygen in the blood, mainly in the arteries. hypoxemia is an indication of an issue associated with circulation or breathing and may lead to various symptoms like shortness of breath.  

the condition is identified by determining the level of oxygen in the blood sample obtained from an artery. it can also be predicted by determining the oxygen saturation of the blood with the application of a pulse oximeter.  

the normal arterial oxygen is about 75 to 100 mm hg. the values underneath 60 mm hg is generally considered with the requirement for supplemental oxygen. the normal pulse oximeter readings generally range between 95 to 100 percent. the values under 90 percent are regarded as low.  

in the given case, the oxygen saturation is measured at 93 percent, hence, there is no need to administer oxygen, that is, one should withhold oxygen.