nucleotides

• DNA nucleotide

  • deoxyribose sugar
  • phosphate group
  • bases= A-T and G-C
• RNA nucleotides

  • ribose sugar
  • phosphate group
  • bases= A-U and G-C
• bonds(both)


  phosphodiester bonds- joining adjacent nucleotides

  hydrogen bonds- joining nitrogenous bases
• purines= A + G, double ring structure

  pyrimidines= C + T + U, single ring structure
• the phosphodiester bond

  • adjacent nucleotides joined via condensation reactions
  • occurs with phosphate group and pentose sugar
  • forms phosphodiester bond
  • consists of phosphate and 2 ester bonds
• DNA structure

  • nucleic acid of DNA is a polynucleotide
  • hydrogen bonds- 2 antiparallel strands of DNA held together by H+ bonds
  • A+T= 2 H+ bonds both via complementary base pairing
  • G + C=3 H+ bonds
• double helix

  • anti-parallel strands
  • sugar-phosphate backbone included
• RNA structure

  • 1 polynucleotide strand, unlike DNA
  • eg MRNA or TRNA
  • same phosphodiester and hydrogen bonds as DNA
  • A + U instead
  • ribose not deoxyribose pentose sugar