Q. An analysis of a DNA (double strandard) sample yielded 18% cytosine. What would be the percentage of other bases in this sample?
A) T- 32%, A-32%, G-18%
B) T-32%, A-18 %, G-32%
C) T-18%, A-32%, G-32%
D) T-40%, A-22%, G-20%
Explanation
According to Chargaff’s rule, in DNA purines and pyrimidines are always in equal proportion ($i.e.,$ A+G=T+C) and proportion of adenine is always equals to that of thymine, while proportion of guanine always equals to that of cytosine ($i.e.,$ A=T and G=C). So, option (a) is correct.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.