CHAPTER 8

• Nucleic acids are polymers of nucleotides used for:

  • Storage of genetic info (DNA)

  • Transmission of genetic info (mRNA)

  •Protein synthesis (tRNA and rRNA
• Nucleotides are also used in the monomer form for cellular functions:

  • Energy for metabolism (ATP)

  • Enzyme cofactors (NAD+)

  • Signal transduction (cAMP)
• Nucleoside: 


  • Nitrogen base

  • Pentose
• Nucleotide:

  • Nitrogen base

  • Pentose

  • Phosphate
• Nucleic acids are build using the 5’-triphosphates version of the nucleotide (ATP, GTP, TTP, CTP)
• PENTOSE FORMS DIFFER IN SOME NUCLEOTIDES AND NUCLEIC ACID:

  • Β-D-ribofuranose in RNA

  Β- 2’-deoxy-D-ribofuranose in DNA
• NITROGEN BASES:

  • Derivatives of pyrimidine or purine
  • Planar or almost planar structures
  • Absorb UV light around 250-270nm
• Cytosine, adenine, guanine are found in both DNA and RNA

  • Thymine is found only in DNA
  • ‐ Uracil is found only in RNA
  • All are good H-bond donors and acceptors
• • Adenine (Adenosine Deoxvadenosine )(Adenylate Deoxyadenylate)(RNA)
  • Guanine (GUANOSINE Deoxyguanylate)(Guanylate Deoxyguanylate)
  • Cytosine (Cytidine Deoxycytidine)
  • Thymine (Thymidine or deoxythymidine)(Thymidylate of deoxythymidylate )Uracil(Uridine)(Undylate)