carbon: nucleic acids

• • nucleic acids: polymers of nucleotide monomers
  • amino acid sequence of a polypeptide is programmed by genes
• function:

  • DNA and RNA enable reproduction of complex information to offspring
  • DNA directs RNA synthesis + controls protein synthesis (gene expression)
• nucleic acids:

  • macromolecules that exist as polynucleotides (polymers) made of nucleotides (monomers)
  • pyrimidine: 1 6-membered ring of carbon + nitrogen atoms (cytosine + thymine + uracil)
  • purine: larger, 6-membered ring fused to 5-membered ring (adenine + guanine)
  • DNA sugar: deoxyribose (lacks oxygen on 2nd carbon ring)
  • RNA sugar: ribose
• nucleotide polymers:

  • nucleotide + nucleotide = polynucleotide via dehydration rxn (bond name= phosphodiester linkage)
  • sugar-phosphate backbone
  • read in 5' (phosphate end) to 3' (hydroxyl group)
• structure of DNA and RNA:

  • DNA: double helix made from 2 polynucleotides
  • 2 sugar-phosphate backbones run antiparallel 5'->3' directions
  • strands held together via Hbonds between paired bases
  • RNA: single strand
  • shapre results from base pairing between nucleotides (antiparallel)