This lecture explores the structure and function of hemoglobin and antibodies, focusing on oxygen uptake, cooperative interactions, and molecular mechanisms for their regulation. It delves into the mutations in hemoglobin genes, the impact of pH on oxygen affinity, and the role of 2,3-bisphosphoglycerate. Additionally, it discusses the unique properties of fetal hemoglobin and the molecular mechanisms behind their regulation. The lecture also covers the production of antibodies in animals, their applications in medicine and research, and the genetic basis of sickle cell anemia.