Basic defect in HbS is?
Correct Answer: Altered solubility
Description: Basic defect in HbS is altered solubility. A molecule of hemoglobin S (HbS) contains two normal a globin chains and two mutant b globin chains- glutamate at position 6 is substituted with valine. This replaces the polar glutamine residue with a nonpolar valine. The replacement of glutamate by valine generates a sticky patch on the surface of HbS. The sticky patch is present on both oxygenated and deoxygenated HbS but deoxygenated HbS also contains a complementary site for the sticky patch. When HbS is deoxygenated the sticky patch present on its surface binds to the complementary patch on another deoxygenated HbS molecule. Binding of a number of deoxygenated HbS leads to formation of long fibrous polymers of HbS. This stiffens and disto the red cells producing rigid misshaped erythrocytes.
Category:
Medicine
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now