Sickle-cell anaemia is a genetic disorder caused by a mutation in DNA. In this mutation, a single base substitution occurs in the gene that codes for the β\betaβ-globin polypeptide of the haemoglobin protein. Explain how this mutation causes a change in the structure of the protein produced. Use your knowledge of DNA, transcription, and translation.
The abnormal haemoglobin causes red blood cells to become rigid and sickle-shaped under low oxygen conditions, which can block small blood vessels. Suggest one symptom a person with sickle-cell anaemia may experience.
Sickle-cell anaemia can be treated using stem cells. Blood-forming stem cells from a healthy donor are transplanted into the patient's bone marrow. Explain why using stem cells from a healthy donor can treat sickle-cell anaemia.