DNA STRUCTURE AND FUNCTIONDIAMSAY, ELISHA GRACE B.MENDOZA, LINETTE M.
Rosalind Franklin used X-ray crystallography to help visualize the structure of DNA.
James D. Watson and FrancisCrick, co-originators of the double- helix model.
What is DNA?DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. Nearly every cell in a person’s body has the same DNA.
Where is it located?Most DNA is located in thecell nucleus (where it iscalled nuclear DNA), but asmall amount of DNA canalso be found in themitochondria (where it iscalled mitochondrial DNA ormtDNA).
FUNCTIONDNA stores an organisms geneticinformation and controls theproduction of proteins and is thusresponsible for the biochemistry ofan organism.
DNA STRUCTURE• The structure of DNA is illustrated by a right handed double helix, with about 10 nucleotide pairs per helical turn• Each spiral strand, composed of a sugar phosphate backbone and attached bases, is connected to a complementary strand by hydrogen bonding (non- covalent) between paired bases, adenine (A) with thymine (T) and guanine (G) with cytosine (C).
Adenine forms 2 bonds with Thymine.Guanine forms 3 bonds with Cytosine.
Sugar - Either ribose or deoxyribose (in RNA or DNA).Nitrogenous base Purines consist of a six-membered and a five- membered nitrogen-containing ring, fused together – Adenine – Guanine Pyridmidines have only a six-membered nitrogen- containing ring. – Uracil (RNA) – Thymine – CytosinePhosphates - One to three, two of which are usually hydrolyzed to provide the energy to attach the nucleotide and form the phosphodiester bond.
Base Pairing of DNA• In a DNA double helix, each type of nucleobase on one strand normally interacts with just one type of nucleobase on the other strand. This is called complementary base pairing• Purines form hydrogen bonds to pyrimidines, with A bonding only to T, and C bonding only to G.