Question

Read the following statements and select the correct option.

(i) Har Gobind Khorana developed a method for synthesising RNA molecules with defined sequences.

(ii) Marshall Nirenberg developed a cell-free system to synthesise proteins and that helped to decipher the code.

(iii) A classic example of point mutation is sickle cell anaemia disease.

Answer 1

Har Gobind Khorana developed a chemical method for synthesising RNA molecules with defined sequences or combinations of bases.

Marshall Nirenberg developed a cell-free system for protein synthesis and this helped to decipher the genetic code.

Sickle cell anaemia is a Mendelian disorder caused due to substitution (point mutation) of a single base pair in the gene for beta globin chain of haemoglobin. It results in the substitution of glutamic acid (Glu) by valine (Val) at the sixth position of the beta globin chain of the haemoglobin. This causes RBCs that are usually biconcave to assume sickle shape. Sickle cells tend to stick together and block small blood vessels causing painful and damaging complications.