The basic building block of your body is a cell. Cells can be classified as either eukaryote or prokaryote cells- with or without a nucleus, respectively. The cells that make up your body and those of all animals, plants, and fungi are eukaryotic.
Prokaryotes are bacteria and cyanobacteria.
All of the genetic information that forms the book of life is stored on individual chromosomes found within the nucleus. Genes are the functional regions along these DNA strands, which are the fundamental physical units that carry hereditary information from one generation to the next. In the prokaryotes the chromosomes are free floating in the cell body since there is no nucleus. The DNA molecules are composed of two interconnected chains of nucleotides that form one DNA strand. Each nucleotide is composed of a sugar, phosphate, and one of four bases.