Hemoglobin binding?

Question

In which one of the following situations would you expect hemoglobin to have the lowest binding affinity for oxygen?
a. just below the surface of the skin on a cold day
b. in actively exercising skeletal muscle
c. in resting skeletal muscle
d. in the lung

I think it is c

Answer 1

B. Excercising skeletal muscle will use up the most oxygen and give off more CO2. Hemoglobin has a low affinity for oxygen in those conditions.

Answer 2

Hemoglobin changes its affinity for o2 depending where it is. In the tissues the affinity is reduced so it can unload o2 to the tissues. I think the question is a bad one since the affinity does not change between resting and exerting tissues, it simply means that more o2 will be given up to the working tissues due to the low o2 tension in those tissues, but the affinity will not change. I would surmise the best answer would be B working tissues.

Answer 3

I think the other answerer is trying to get to is, what does it mean if Hb has a lower binding affinity for O2?

Hb can be described as a carrier molecule so it's binding affinity becomes lower as it gets nearer to a site where O2 is needed. This happens because Hb undergoes a conformational change when it is in a region of high CO2, this conformational change releases O2 from its binding site (it is really a cool process that you should look into...it helps me if I can think about what the molecule is doing physically).

So basically high CO2 causes a decrease in Hb affinity for O2.

So...I hope that helps.

Answer 4

SInce its homework, I rather let you think for a while. When and where your body needs oxygen. Why would a resting muscle needs oxygen so much, compared to the active one. Whast does the lung do. What does cold air has to do with oxygen affinity.