The Structure And Composition of DNA

[cs_content][cs_section parallax=”false” separator_top_type=”none” separator_top_height=”50px” separator_top_angle_point=”50″ separator_bottom_type=”none” separator_bottom_height=”50px” separator_bottom_angle_point=”50″ style=”margin: 0px;padding: 45px 0px;”][cs_row inner_container=”true” marginless_columns=”false” style=”margin: 0px auto;padding: 0px;”][cs_column fade=”false” fade_animation=”in” fade_animation_offset=”45px” fade_duration=”750″ type=”1/1″ style=”padding: 0px;”][cs_text]Forensic Chemistry > 4. DNA is an important compound found in all living things and is a most useful identification molecule > The Structure And Composition of DNA >[/cs_text][cs_text style=”color: #800000;font-family: “Oxygen”,sans-serif;”]Outline the structure and composition of DNA[/cs_text][cs_text]Deoxyribonucleic acid (DNA)

  • A form of nucleic acid which are made up of its building blocks called nucleotides covalently linked together by 3’,5’- phosphodiester linkages
  • In DNA, the nucleotides are composed of an aldopentose (2-deoxyribose) bonded to a phosphate group and linked to a heterocyclic purine and pyrimidine bases (nitrogenous bases)

Purine:

    • Adenine (A)
    • Guanine (G)

Pyrimidine:

      • Cytosine (C)
      • Thymine (T)

[/cs_text][cs_text][/cs_text][cs_text]Structure of DNA

      • Primary Structure
        • consist of alternating sugar-phosphate backbone with different nitrogenous bases attached onto it
        • Its individual nucleotides are connected via a phosphate ester linkage between the 5’-phosphate group on one nucleotide residue and the 3’-hydroxyl on the sugar of another nucleotide residue

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        • Secondary Structure
          • consist of two polynucleotide strands coiled around each other in a double helix
          • The two antiparallel strands which are held together by hydrogen bonds pairs are complementary due to specific base pairing

Chargaff’s rule

          • %A = %T
          • %C = %G

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