Affinity for Oxygen- myoglobin?

Question

which of the following has the highest affinity for oxygen?

a) tissues at rest

b) tissues during exercise

c) myglobin

d) hemoglobin

i'm kind of going back and forth from C to D... which one is the better answer?

Answer 1

According to me, it has to be haemoglobin b'coz it's the most important protein complex which supplies cells and tissues with oxygen ,even muscles which have myoglobin get oxygen from oxyhaemoglobin.Also it's the second fastest working complex first being acetyl coline.

Answer 2

It is definitely not A, tissues during exercise go into oxygen debt and require more oxygen, so B has a higher affinity for O2

It is definitely not C, hemoglobin has what's called cooperative binding. Meaning, for each O2 that binds to hemoglobin increases affinity for the next O2. Myoglobin is just a monomer so it cannot take advantage of cooperative binding.

However, it depends on what area of the body to determine between B and D. Tissues during exercise have a low pH and a high CO2 concentration. This helps reduce hemoglobin's affinity for O2 so it will release it at the tissues. However, at the alveoli in the lungs, where pH is higher and CO2 concentration is very low, hemoglobin's O2 affinity is much higher.

If there is no other information I'd say chose B because B takes O2 from D. It's just tough to say for sure because hemoglobin's O2 affinity varies around the body.

Edit: While it is true that myoglobin initially has higher affinity for O2 than hemoglobin, but in the presence of fresh air in the lungs, hemoglobin has higher affinity for O2 than myoglobin. There are just too many variable to consider for there to be a definite answer to this question.

Answer 3

its C .

myoglobin has a higher affinity...