Question

Write a note on the affinity of hemoglobin.

Answer 1

Blood has components like- red blood cells and white blood cells and platelets also buffers for maintaining blood’s pH and balance. Hemoglobin is the iron pigment present in blood whose major role is to provide the red color in blood. Hemoglobin has an affinity between the oxygen saturation and oxygen tension.

Complete answer:
Hemoglobin binds to several factors like- pH, temperature, carbon-monoxide. The affinity of hemoglobin is affected by these factors. Hemoglobin carries oxygen molecules efficiently from the lungs to the tissues in the body and hence show low affinity towards oxygen.
As the heme group binds to oxygen, they become progressively easier for subsequent heme groups of the molecule to select up oxygen. Hemoglobin carries oxygen from lungs to all the tissues present in the body, where aerobic respiration takes place. Aerobic respiration holds the power of metabolism which provides energy to perform activities in the body.
As we all know, hemoglobin is the component found in blood. Hemoglobin binds to four oxygen molecules. It is the iron content in hemoglobin which provides blood red color. Myoglobin is a monomeric protein whereas hemoglobin is an oxygen transport protein which is heterotetrametric. Myoglobin serves as an intracellular storage site for oxygen.
The oxygen hemoglobin dissociation curve also referred to as the oxygen dissociation curve plots the proportion of hemoglobin in its saturated oxygen-laden form prevailing oxygen tension on the horizontal axis. The graph shows the partial pressure of oxygen along the horizontal axis and oxygen saturation in the vertical axis.
Factors affecting affinity of hemoglobin are-
Partial pressure of carbon-dioxide- increased carbons shift the curve to the right and hyperventilation and hypocapnia shifts the curve to the left.PH also matter in case of carbon-dioxide. Decreased pH known as acidosis shifts the curve to the right. Alkalosis curve shifts to the left.

Note:
Oxygen curves can be sigmoid and hyperbolic depending on different factors. Hemoglobin is a tetramer while myoglobin is a monomer both have their affinities towards oxygen. Sulfa hemoglobin shifts the curve towards the right. The presence of unusual species of hemoglobin are methemoglobin, carboxyhemoglobin, and fetal hemoglobin all shift the curve to the left. Temperature also affects hyperthermia shifts the curve to right and hypothermia shifts the curve to left. The graph or the curve is the sigmoid shape which is independent of all allosteric factors.