Fetal Hemoglobin

in this video, we're going to talk about fetal hemoglobin. So it turns out that the human fetus actually has structurally different hemoglobin than the adult hemoglobin that we've been talking about all along. And the reason for this is because it's important for the human fetus to be able to obtain oxygen from its mother's blood. And so fetal hemoglobin, which we're going to abbreviate as F H B moving forward, actually has to gamma sub units. And here's the Greek letter Gamma rather than to beta subunits like the adult hemoglobin has. And so you could see that fetal hemoglobin structure is to Alfa sub units and two gamma sub units, where, as the adult hemoglobin recall has to Alfa and two beta subunits. So again it has these gamma subunits instead of the beta subunits. And so this structural difference in fetal hemoglobin allows fetal hoop hemoglobin toe have a lowered affinity for B p G and recall that B P G is a negative hetero, tropic Alice derek inhibitor. And so, if fetal hemoglobin has a low affinity for an inhibitor that's going to correlate with even greater or even stronger oxygen affinity and so fetal hemoglobin has a stronger oxygen affinity than adult hemoglobin, and this allows for oxygen gas to flow from the maternal oxy hemoglobin HBO to towards the fetal deok ce myoglobin FHP allowing the fetal hemoglobin to obtain oxygen. And so, if we take a look down below at our oxygen saturation curve notice on the Y axis, we have the fractional saturation data. Or why and on the X axis. We have the partial pressure of oxygen and units of tours, and we've got these two different curves here. We've got the screen curve, and we've got this red curve and notice that the green curve corresponds with fetal hemoglobin, whereas the red curve corresponds with adult hemoglobin. And so recall adult hemoglobin has to alfa sub units as well as to beta subunits, whereas the fetal hemoglobin, on the other hand, has the same to Alfa sub units. But instead of having the beta subunits, it actually has gamma sub units, and that's my horrible symbol for gamma. But it's really supposed to be the gamma sub unit up here, and so essentially again with this allows for is fino. Hemoglobin is going to have a stronger oxygen affinity due to having a lowered affinity for B P G. And so you can see that the oxygen flow here is going to go from the adult hemoglobin towards the fetal hemoglobin, allowing the fetus to obtain oxygen from its mother's blood. So oxygen is going to flow from the, uh, maternal or adult hemoglobin to the fetal hemoglobin. And so, if we take a look at our example, it's asking us, according to the dissociation, constant K d. In the plot below which hemoglobin has a stronger affinity for oxygen. So we can see that for this green curve right here. The K D is lower than the K D for the adult hemoglobin. And, of course, a lower K D here corresponds with a stronger affinity. And so thehyperfix loving that has the stronger affinity for us soon is going to be fetal hemoglobin, so we can indicate that be here is the correct answer for this example problem. And that concludes this example and this lesson on fetal hemoglobin, and we'll be able to get some practice as we move forward in our course. So I'll see you guys in our next video

Fetal hemoglobin binds oxygen with a ___________ affinity than adult hemoglobin, because it lacks the binding site for ______, which is an allosteric ____________ of oxygen binding to adult hemoglobin.

• A. Lower ; BPG ; inhibitor.
• B. Higher ; H+ ; inhibitor.
• C. Higher ; BPG ; activator.
• D. Higher ; BPG ; inhibitor.
• E. Lower ; CO ; inhibitor.