What are the two major pyrimidines present in RNA?

The two major pyrimidines found in RNA are cytosine and uracil. Pyrimidines are one of the two categories of nitrogenous bases, the other being purines. In RNA, uracil replaces thymine, which is found in DNA.

Cytosine is a key component found in both DNA and RNA. Its structure features a single six-membered ring, characterized by a nitrogen and carbon configuration, allowing it to effectively pair with guanine, a purine.

Uracil, also a pyrimidine, has a similar structure to thymine but lacks a methyl group that thymine possesses. This small difference significantly influences the function of RNA in cellular processes, such as protein synthesis. In RNA, uracil pairs with adenine, much like thymine pairs with adenine in DNA.

Understanding the specific roles and structures of these bases is crucial for grasping the biochemistry of nucleic acids and their functions in various biological systems.