Question

Which of the following is found only RNA and not in DNA?

• A. Adenine
• B. Thymine
• C. Guanine
• D. Uracil

Answer 1

Answer: (D)

In RNA, Uracil is found but absent in DNA. In RNA, uracil binds to adenine via two hydrogen bonds. In DNA, the uracil nucleobase is replaced by thymine. Uracil could be considered a demethylated form of thymine. Each nucleotide in RNA contains a ribose sugar, with carbons numbered 1' through 5'. A base is attached to the 1' position, in general, adenine (A), cytosine (C), guanine (G), or uracil (U). Adenine and guanine are purines, cytosine and uracil are pyrimidines.

So, the correct answer is option D.