Q 1 Sickle cell Anemia is called as Molecular disease
Answer :
HbA is made up of 2 alpha and 2 beta chain... Beta chain is synthesized from chromosome 11..
In SCD there is mutation of T-> A in DNA ..Normally 6th position of Amino acid Glutamic acid is there ..
Normally in DNA CTC code for 6 th position of Glutamic acid in beta chain
Due to T to A mutation ..Now CTC is replaced by CAC... while transcribed GAG is replaced to GUG...
GAG code for gluamic acid.. but due to mutation of T to A... codon replaced to GUG ..Now GUG code for valine
SO here due to point mutation in DNA... Glutamic acid replaced by valine amino acid which is non polar leading to sticky patches and sickel shape RBC leading to blocking microvasculature leadning to painful crisis