Question

The biochemical analysis Red blood cells (erythrocytes) and sickle cell anemia (which can lead to a splenic infraction on high altitude):

QA) Sickle cell anemia is a genetic disease that is caused by a single nucleotide change in the gene sequence for hemoglobin. This mutation changes a codon from GAG to GUG, which causes an alteration in the hemoglobin protein, changing what is typically an E into a V. Explain and compare the properties of E and V that make this mutation so important.

QB) Sickle cell attacks are often brought on by strenuous activity (like athletic activity) or by high altitude (like visiting Denver). Given what is known about sickle cell anemia and about hemoglobin function, explain this result on a molecular level.  A full answer will include all the relevant conditions introduced in this scenario.

QC) When red blood cells (erythrocytes) are stored, they lose their BPG over time, lowering the BPG concentration. Considering this, compare the oxygen affinity and transport efficiencies of week-old donated blood vs freshly donated blood for transfusion into a patient, and explain your answer in terms of hemoglobin structure & function.

Answer 1

A)The point muation in beta-globin chain of hemoglobin in sickle cell anemia is important because it replaces the hydrophillic amino acid glutamic acid (E) to hydrophobic amino acid valine (V) at 6th position. So, the absense of polar amino acid promotes non-convalent polymerisation or agregation of hemoglobin causes the sickle shape of RBC.

B)At high altitude, RBCs with sickle shaped with less elasticity were not able to carry oxygen near to normal RBC and get intrapped in capillaries causing no blood supply to the vital organs and resulting into splenic infarction.