Question

Purines found both in DNA and RNA are

• A. cytosine and thymine
• B. adenine and thymine
• C. adenine and guanine
• D. guanine and cytosine

Answer 1

The correct option is C adenine and guanine

DNA and RNA are polymers of nucleotides. A nucleotide has three components: pentose sugar, nitrogenous base and phosphate group.

There are two types of nitrogenous bases in DNA and RNA – purines
(adenine and guanine), and pyrimidines (cytosine, uracil and thymine).

The purines present in both DNA and RNA are adenine and guanine.

But the pyrimidines differ in DNA and RNA. In DNA, the pyrimidines are thymine and cytosine whereas the pyrimidines in RNA are cytosine and uracil.

Hence, RNA has uracil and DNA has thymine in place of uracil.