The human genome consists of all the DNA within the cells. The DNA resides within the 46 chromosomes
of the human body, which are found in a cell's nucleus. Chromosomes are composed of proteins and nucleic acids. Nucleic acid
can be either double stranded (DNA) or single-stranded (RNA). RNA is the molecule that reads and transfers the genetic code
to the robosome in the cytoplasm where proteins are formed. DNA, or deoxyribonucleic acid, contains the body's genetic information.
DNA has all of the instructions needed for protein and cell formation.
Nucleotides, the building blocks of nucleic acids, are made up of phosphate, sugar and one of four
chemicals called nitrogen bases. The nitrogen bases are Adenine, Thymine, Guamine and Cytosine. One nucleotide is complementary
to another and these two fit together by means of a hydrogen bond. Adenine pairs with Thymine, and Guanine pairs with Cytosine.
These base pairs assemble in a sequence that makes the double-stranded helix of DNA.
It is estimated that there are approximately 3 billion base pairs of DNA and 100, 000 genes situated on
the chromosomes in the human genome. Each gene on a chromosome has a specific sequence of nucleotide bases. It's this
order that is used to distinguish one gene from another.