The DNA or deoxyribonucleic acid is composed of a pentose sugar,
a base and phosphate group. The bases are adenine, thymine, cytosine and
guanine. Guanine always forms hydrogen bonds with cytosine. Remember the
statement “Apples in the Tree, Cars in the Garage”. The A stands for adenine
and pairs with T-thymine then C – cytosine and G – guanine.
