DNA is deoxyribonucleic acid - double helix. The sequence of the nucleotides is the basis of genetic information. The Expression of Genetic Information DNA contains a sequence of nucleotides. Every 3 nucleotides is called a codon. Each codon encodes for a particular amino acid.
Amino acids are the building blocks of proteins.
So, genes are places on the DNA of Chromosomes which code for particular proteins. These proteins create the phenotypic characteristics of the organism. Nucleotides - divided into codons of 3 nucleotides. Codons - each represents an amino acid. The information of the genetic code is contained as a long sequence of nucleotides which code for proteins.