Question

Which nucleotide is in RNA but not in DNA?

1) Thymine
2) Adenine
3) Cytosine
4) Guanine
5) Uracil

Answer 1

Uracil is the nucleotide found in RNA but not in DNA; it replaces thymine in RNA and pairs with adenine.

Step-by-step explanation:

The nucleotide that is in RNA but not in DNA is uracil. While DNA contains the nitrogenous bases adenine (A), guanine (G), cytosine (C), and thymine (T), RNA contains adenine, guanine, cytosine, and uracil (U) instead of thymine. Uracil in RNA pairs with adenine just as thymine does in DNA, and it is important to note that uracil is considered an unmethylated form of thymine.