3G2+Bio+DNA+Essay+by+Yichen,+Woon+Wei+and+Ryo

Ryo Yap - Blue Wei Yichen - Green Look Woonwei - Red =__DNA__ =

The term DNA we often use refers to __//deoxyribonucleic acid//__, which is essentially a nucleic acid that contains the genetic instructions used in the development and functioning of every single living orgasm on Earth. The primary application of DNA is the long-term storage of information, which allows it to contain the necessary instructions to construct other components of cells, including protein, that is essential for the growth and repair of muscles, thus highlighting the significance of DNA. In which, genes are responsible for containing and transporting this genetic information. Chemically, DNA is composed by two long polymers of simple units called nucleotides that contain deoxyribose, with backbones made of sugars and phosphate groups joined byester bonds.  
 * These nucleotides can be categorized into two groups: purines that include adenine and guanine, and pyrimidines that include thymine and cytosine.
 * The backbone of the DNA strand comprises of alternating phosphate and sugar residues. This sugar refers to deoxyribose, a monosaccharide containing five carbon atoms. These sugars are then joined together by phosphate groups that form phosphodiester bonds between the third and fifth carbon atoms of adjacent sugar rings.

These long polymer strands entwine around one another, forming the shape of a double helix, in an anti-parallel fashion. These repeated chains of polymer strands also contain a base ,besides the backbone, that connects and more importantly, interacts with the other DNA strand in the helix. The DNA double helix structure would then be connected and essentially stabilized by hydrogen bonds between the bases and the two strands of polymers. These bases that link the nucleotides are refered to as nucleosides and once they are linked to a sugar and one or more phosphate groups, they will be recognised as nucleotides. Multiple strands of these nucleotides are linked together, forming DNA, a polynucleotide.  Sources: Wikipedia - Basic referencing and knowledge gathering - [] US national library of Medicine - Picture - [] GCE O Levels Biology Matters - Marshall Cavendish Education - by Lam Peng Kwan - Bulk of information and general knowledge gathering