Adenine (A)

Adenine is a type of purine base that is used to make one of the building blocks of DNA and RNA. It bonds with thymine in DNA.

Guanine (G)

Guanine is a type of purine base that is used to make one of the building blocks of DNA and RNA. It bonds with cytosine in DNA.

Cytosine (C)

Cytosine is a type of pyrimidine base that is used to make one of the building blocks of DNA and RNA. It bonds with guanine in DNA.

Thymine (T)

Thymine is a type of pyrimidine base that is used to make one of the building blocks of DNA. It bonds with adenine in DNA.

DNA strand

Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups.