Question

An analysis of a DNA (double stranded) 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. $ 1-40\%, A-22\%, G-20\% $

Answer 1

Answer: (A)

According to Chargaff's rule, in DNA purines and pyrimidines are always in equal proportion (ie, $A+G=T+C$ ) and proportion of adenine is always equals to that of thymine, while proportion of guanine always equals to that of cytosine (;e, $A=T$ and $G$ $= C)$.