Question

When the base composition of double-stranded DNA from Micrococcus luteus was determined, 37.5% of the bases were found to be cytosine. What is the percentage of adenine in the DNA of this organism?________ % adenine.

Answer 1

12.5% Adenine

Step-by-step explanation:

According to Chargaff who proposed the complementary base pairing rule in DNA, the concentration of bases (purine and pyrimidines) is equal to 100% i.e. A+T+G+C= 100%.

Since Cytosine pairs with Guanine, there would be an equal amount of both in the DNA molecule i.e. Cytosine=Guanine=37.5%

37.5 (C) + 37.5 (G) = 75%

100 - 75 = 25%

Hence, we have 25% left to share among Adenine and Thymine, which will contain equal amount. 25/2 = 12.5%.

Both Adenine and Thymine will have 12.5% each.