noun
- A nitrogenous base that is one of the four main components of DNA and RNA, pairing with guanine.
Usage: biochemistry; molecular biology
Examples
- Cytosine is one of the pyrimidine bases found in all living cells.
- In DNA, cytosine always pairs with guanine through hydrogen bonds.
- The sequence of adenine, thymine, guanine, and cytosine determines genetic information.
- Cytosine can undergo methylation, which affects gene expression.
- RNA contains cytosine instead of thymine as one of its four bases.