Pyrimidines

Definition

Pyrimidines are one of the two types of nitrogenous bases found in nucleic acids, characterized by a single six-membered ring structure. They include cytosine, thymine (in DNA), and uracil (in RNA).

5 Must Know Facts For Your Next Test

1. Pyrimidines pair with purines through hydrogen bonding in the DNA double helix.
2. In DNA, cytosine pairs with guanine and thymine pairs with adenine.
3. In RNA, uracil replaces thymine and pairs with adenine.
4. Pyrimidines are synthesized through a different metabolic pathway compared to purines.
5. Mutations or alterations in pyrimidine metabolism can lead to genetic disorders.

Review Questions

• What are the three pyrimidines found in nucleic acids?
• How do pyrimidines pair with purines in the DNA double helix?
• What is the difference between the pyrimidines found in DNA versus RNA?

Related terms

Purines: Nitrogenous bases characterized by a double-ring structure; includes adenine and guanine.

Nucleotides:

The basic building blocks of nucleic acids composed of a nitrogenous base, a sugar, and a phosphate group.

Base Pairing:

The specific hydrogen bonding between purines and pyrimidines in DNA and RNA.