Chromosomes
Chromosomes are made from very long molecules of DNA. Each molecule is in ladder-like
shape, with the “rungs” being made from a pair of nitrogenous bases, known as A, T, G and C,
and the side made from repeated pentose sugars and phosphate groups. A group of one base,
one pentose molecule and one phosphate together is known as a nucleotide and DNA can be
regarded as a polymer of these nucleotides.