DNA: Difference between revisions
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DNA strands are primarily composed of three repeating units: | DNA strands are primarily composed of three repeating units: | ||
* | *[[2-Deoxyribose sugar|2-Deoxyribose sugar]] - A five [[Carbon|carbon]] sugar (pentose) similar to that of [[Ribose|Ribose]] sugar found in [[RNA|RNA]]. Its chemical formula is C<sub>5</sub>H<sub>10</sub>O<sub>4</sub> | ||
[[2-Deoxyribose sugar|2-Deoxyribose sugar]] - A five [[Carbon|carbon]] sugar (pentose) similar to that of [[Ribose|Ribose]] sugar found in [[RNA|RNA]]. Its chemical formula is C<sub>5</sub>H<sub>10</sub>O<sub>4</sub> | |||
*[[Phosphate group|Phosphate group]] - Contains one [[Phosphorus|phosphorus]] [[Atom|atom]], bonded to 4 [[Oxygen|oxygens]]. Forms a [[Phosphodiester bond|phosphodiester bond]], which connects 2 [[Deoxyribose sugars|deoxyribose sugars]] together resulting in the formation of a chain | *[[Phosphate group|Phosphate group]] - Contains one [[Phosphorus|phosphorus]] [[Atom|atom]], bonded to 4 [[Oxygen|oxygens]]. Forms a [[Phosphodiester bond|phosphodiester bond]], which connects 2 [[Deoxyribose sugars|deoxyribose sugars]] together resulting in the formation of a chain | ||
Revision as of 19:38, 21 November 2010
DNA (deoxyribonucleic acid) is the genetic information found in the nuclei of most organisms. It is arranged into structures called chromosomes. The structure of DNA was identified as being a 'double-helix' by Watson and Crick in 1953.
DNA is composed of 4 bases; the purines: Adenine (A) and Thymine (T) and the pyrimidines: Guanine (G) and Cytosine (C). These form complementary bases pairs of AT and GC. DNA also contains a phosphate group connected to a deoxyribose sugar.
Structure of DNA
DNA strands are primarily composed of three repeating units:
- 2-Deoxyribose sugar - A five carbon sugar (pentose) similar to that of Ribose sugar found in RNA. Its chemical formula is C5H10O4
- Phosphate group - Contains one phosphorus atom, bonded to 4 oxygens. Forms a phosphodiester bond, which connects 2 deoxyribose sugars together resulting in the formation of a chain
- A base - One from Adenine, Cytosine, Guanine or Thymine. This forms a side chain branching from the 2-deoxyribose sugar (the 2-Deoxyribose sugar/Phosphate group region is regarded as the 'backbone' of DNA strands)
The complementary base pairs in DNA interact with one another via hydrogen bonds:
- A-T interactions consist of 2 intermolecular hydrogen bonds
- G-C interactions consist of 3 intermolecular hydrogen bonds
These interactions form bridges between two [DNA|DNA]] chains, thus creating a double stranded 'ladder' shaped structure.