Though CO is hindered in its binding to Hb by the distal His, Hb\'s affinity for
ID: 196830 • Letter: T
Question
Though CO is hindered in its binding to Hb by the distal His, Hb's affinity for CO is nonetheless about 200 times that for oxygen. Like oxygen, CO shows positive cooperativity in binding to the heme sites of Hb. A molecule of CO and molecule of oxygen can bind to the Hb tetramer at the same time, though at different binding sites. Use this information to analyze the following clinical situation. Two people present in a hospital emergency room. John's blood Hb concentration is one-half the normal value (only ½ the normal number of Hb molecules are present). David has been poisoned with CO by car exhaust, such that the number of oxygen-binding sites available to bind oxygen is only ½ the normal value (because, on average, every Hb molecule has 2 CO bound to 2 of its 4 hemes). Assuming that John and David are otherwise similar, which patient is in more serious danger and why? (4 pts)Explanation / Answer
if we suppose the normal number of Hb is 100 in the body.
Total sites = 100*4-100*2
= 400-200
= 200
The total number of sites in both are same so we can't decide the seriousness on the basis of sites.
lests look at the affinity the affinity of the CO is much higher then the O2 to Hb which lower the dissociation of oxygen from Hb which means in the case of david if the remaining 200 sites occupied by oxygen but they will not able to release it in peripheral system which causes hypoxia. we can say both have same number of sites for oxygen but david's condition is more serious then the John because CO decreases the dissociation of oxygen.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.