In sickle cell, haemoglobin molecule, glutamic acid, is replaced by:

Explanation

Option C is correct. In sickle cell anemia, glutamic acid in the hemoglobin molecule is replaced by valine. This single amino acid substitution leads to the hemoglobin molecules becoming sticky and clumping together when oxygen levels are low. This causes the formation of sickle-shaped red blood cells, which can obstruct blood vessels and lead to severe complications such as pain, stroke, and other health issues. Sickle cell anemia is a genetic condition resulting from a mutation in the hemoglobin gene and is especially prevalent among individuals of African descent. The other options (Proline, Glutamine, Glycine) do not correctly identify the amino acid involved in this specific mutation, and therefore, do not explain the pathology of sickle cell anemia.