Deoxyribonucleic Acid (DNA)

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Deoxyribonucleic Acid (DNA)

Deoxyribonucleic acid (DNA) is a genetic information storage system.
  • DNA is a polymer of nucleotides.
  • Nucleotides are phosphorylated nucleosides.
  • Nucleosides are composed of ribose sugar and a nitrogen base.
Four nitrogen bases have been identified:
  • Purine bases: adenine and guanine
  • Pyrimidines bases: cytosine, thymine, and uracil in RNA
The DNA double helix contains two DNA strands held together with phosphodiester bonds.
  • Adenine:Thymine (A:T) with 2 hydrogen bonds
  • Guanine:Cytosine (G:C) with 3 hydrogen bonds
These strands run in parallel directions:
  • 5'------3'
  • 3'------5'
1. "Deoxyribonucleic Acid (DNA)." National Human Genome Research Institute. Updated March 6, 2024. Available at: https://www.genome.gov/genetics-glossary/Deoxyribonucleic-Acid.

Structure of DNA. (1)