What is the Difference Between Cytosine and Thymine?

Cytosine and thymine are both nitrogenous bases found in nucleic acids, but they have some key differences:

1. Presence in nucleic acids: Cytosine is found in both DNA and RNA, while thymine is found only in DNA. In RNA, thymine is replaced by a base called uracil.
2. Chemical formula: Cytosine has a chemical formula of C4H5N3O, while thymine has a chemical formula of C5H6N2O2.
3. Complementary base pairing: Cytosine pairs with guanine in both DNA and RNA, forming three hydrogen bonds. Thymine, on the other hand, pairs with adenine in DNA, forming two hydrogen bonds.
4. Structure: Cytosine has an amine group at the C4 position and a keto group at the C2 position. Thymine has two keto groups at the C2 and C4 positions and a methyl group at the C5 position.

In summary, cytosine is a pyrimidine base found in both DNA and RNA, pairing with guanine and forming three hydrogen bonds. Thymine is also a pyrimidine base but is found only in DNA, pairing with adenine and forming two hydrogen bonds.

Comparative Table: Cytosine vs Thymine

Here is a table comparing the differences between cytosine and thymine:

Cytosine and thymine are both nitrogenous bases with a heterocyclic aromatic ring. They are part of the four nucleotide bases found in DNA (deoxyribonucleic acid), which stores genetic information. Cytosine pairs with guanine, while thymine pairs with adenine in DNA.