Hemoglobin

Question 1

Composition

Answer 1

4 polypeptides (2alpha and 2 beta)

Question 2

Forms

Answer 2

T (taut): low affinity for O2
R (relaxed): high affinity for O2 (x300)

“Taut in Tissue, Relaxed in Respiratory”

Question 3

Regulation of hemoglobin by O2

Answer 3

Positive cooperativity

negative allostery

Question 4

What favors taut form?

Answer 4

High Cl-, H+, CO2, 2,3-BPG and temprature.
Shifts dissociation to the right,
leading to O2 unloading.

Question 5

Fetal hemoglobin

Answer 5

2alpha and 2gammas
Lower affinity for 2,3-BPG than adult
Thus higher affinity for O2