Question

How do the bases thymine and uracil differ?

Short answer

The chemical structures of uracil and thymine are remarkably similar. The sole difference is that thymine has a methyl group at C-5. Uracil is present solely in RNA, whereas thymine is found only in DNA.

Step-by-step solution

Given information

We need to find the difference between thymine and uracil.

Explanation

In nucleic acids, uracil and thymine are two pyrimidine nucleotides. The pyrimidine ring is a carbon and nitrogen-based heterocyclic aromatic structure. Uracil and thymine have chemical structures that are very similar. Thymine has a methyl group at C-5, which is the only difference. Uracil is exclusively found in RNA, while thymine is only found in DNA. The distinction between uracil and thymine is this. The inclusion of thymine in DNA's strand makes it more stable than RNA. 5-fluorouracil (5-fU) is used in cancer therapy to replace both uracil and thymine during DNA replication. This stops DNA synthesis in cells that are actively proliferating.