nucleic acids

• DNA bases:

  • adenine
  • thymine
  • cytosine
  • guanine
• DNA : deoxyribosenucleic acid
• bond between 2 nucleotides

  phosphodiester bond
• chain of phosphates and sugar in polynucleotides

  sugar phosphate backbone
• how are phosphodiester bonds formed between two nucleotides 

  • through a condensation reaction (loss of water) between a phosphate group and a deoxyribose sugar and is catalysed by DNA polymerase
• complemetary base pairing:

  • cytosine - guanine : 3 hydrogen bonds
  • Adenine - thymine : 2 hydrogen bonds
• DNA replication

  • unwind the double helix - breaks the hydrogen bonds between complementary base pairings using DNA helicase
  • free DNA nucleotides in the nucleus align with exposed bases on template strands - DNA polymerse joins them
• role of RNA:

  • transfer genetic information
  • binds with proteins to form ribosomes