Class 12 NEET Biology Molecular Basis of Inheritance Questions Part 2

Sickle cell anemia is caused by a single point mutation in the gene for the beta globin chain of hemoglobin.
(A) is correct because the mutation occurs in the gene for beta globin.
(B) is incorrect because, in sickle cell anemia, there is a change in the beta globin chain where valine is substituted for glutamic acid, not lysine.
(C) is correct because sickle cell anemia is caused by a single point mutation, which is a change in a single nucleotide in the DNA.
(D) is incorrect because the statement does not accurately describe the genetic mutation. In the normal gene, the DNA code is GAG, which codes for glutamic acid, but in sickle cell anemia, this is changed to GTG, which codes for valine. This does not involve replacing uracil (U) with adenine (A) as the statement suggests.