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EXPLAIN THE STRUCTURE & FUNCTION OF DNA.
DNA is o­ne of the nucleic acids, information-containing molecules in the cell (ribonucleic acid, or RNA, is the other nucleic acid). DNA is found in the nucleus of every human cell.  The information in DNA:
guides the cell (along with RNA) in making new proteins that determine all of our biological traits gets passed (copied) from one generation to the next.
Watson and Crick discovered that DNA had two sides, or strands, and that these strands were twisted together like a twisted ladder -- the double helix. The sides of the ladder comprise the sugar-phosphate portions of adjacent nucleotides bonded together. The phosphate of one nucleotide is covalently bound (a bond in which one or more pairs of electrons are shared by two atoms) to the sugar of the next nucleotide. The hydrogen bonds between phosphates cause the DNA strand to twist. The nitrogenous bases point inward on the ladder and form pairs with bases on the other side, like rungs. Each base pair is formed from two complementary nucleotides (purine with pyrimidine) bound together by hydrogen bonds. The base pairs in DNA are adenine with thymine and cytosine with guanine.
The primary function of DNA in organisms is to store and transmit the genetic information that tells cells which proteins to make and when to make them.


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