1. Tardigrade
  2. Question
  3. Biology
  4. If the total amount of adenine and thymine in a double-stranded DNA is 60%, then the amount of guanine in this DNA will be

Q. If the total amount of adenine and thymine in a double-stranded DNA is 60%, then the amount of guanine in this DNA will be

 242  168 NTA AbhyasNTA Abhyas 2020 Report Error

Solution:

Purine and pyrimidine nitrogenous base is found in DNA. Among purines, adenine pairs only with the pyrimidine thymine. Similarly, guanine pairs with the cytosine. The fact that the total amount of purine will be equal to the total amount of pyrimidine was first enunciated by Chargaff in 1950. From this law,
Adenine=Thymine=60/2=30%
Guanine=Cytosine=40/2=20%