Question
Biology Question on Structure of DNA and RNA
Which base is present in RNA but not in DNA?
A
Uracil
B
Thymine
C
Guanine
D
Cytosine
Answer
Uracil
Explanation
Solution
Nucleic acids are long chain linear polymer of four types of nucleotide monomers, which are linked by phosphodiester bonds. Nucleotide molecule is composed of a nitrogenous base, pentose sugar and a phosphate group. The nitrogenous bases are of two types i.e., purine and pyrimidine. The purine bases are adenine and guanine whereas the pyrimidine bases are cytosine, uracil and thymine. RNA is differ from DNA due to presence of uracil base (at the place of thymine) and in the structure of pentose sugar.