DNA Function

DNA usually occurs as linear chromosomes in eukaryotes, and circular chromosomes in prokaryotes. The set of chromosomes in a cell makes up its genome; the human genome has approximately 3 billion base pairs of DNA arranged into 46 chromosomes. The information carried by DNA is held in the sequence of pieces of DNA called genes.

Transmission of genetic information in genes is achieved via complementary base pairing. For example, in transcription, when a cell uses the information in a gene, the DNA sequence is copied into a complementary RNA sequence through the attraction between the DNA and the correct RNA nucleotides.

Usually, this RNA copy is then used to make a matching protein sequence in a process called translation, which depends on the same interaction between RNA nucleotides.

The structure (shape) and function of the thousands of proteins in an organism is controlled by the order of the amino acids in the protein, and therefore is ultimately controlled by the sequence of bases on the DNA.

In alternative fashion, a cell may simply copy its genetic information in a process called DNA replication. The details of these functions are covered in other articles; here we focus on the interactions between DNA and other molecules that mediate the function of the genome.

Many proteins and enzymes are involved in the process of DNA replication, one particular group the DNA polymerases are now used in the analysis traces of DNA found at a crime scene as part of a technique known as Polymerase Chain Reaction (PCR).

Source from: Wikipedia