Recording-2025-09-05T20:08:19.013Z

Carbohydrates

  • Monomer: monosaccharide; general formula for repeating unit: CH2OCH_2O; carbohydrate monomer is a simple sugar.
  • Polymers: polysaccharides; bonds between monomers are glycosidic linkages; formation by dehydration synthesis; hydrolysis breaks them (adds water).
  • Structural options: long chains, isomers, and ring forms; ring structures provide diagnostic features.
  • Key isomers: α\alpha-glucose vs β\beta-glucose determine function.
    • α\alpha-glucose: energy storage (e.g., starch in plants, glycogen in animals) and is digestible by humans.
    • β\beta-glucose: structural support (e.g., cellulose in plants; chitin in fungi/crustaceans).
  • Major polysaccharides and roles:
    • Starch (plants) and glycogen (animals): energy storage; both based on α\alpha-glucose.
    • Cellulose (plants): structural support; made from β\beta-glucose; linear chains.
    • Chitin (fungi, crustaceans): structural support; modified polymer.
  • Recognition cues: presence of ring form and isomer type helps identify carbohydrate type.
  • Summary relation to function: structure and isomer type (alpha vs beta) determine energy storage vs structural roles.
  • Important recurring concepts: dehydration synthesis and hydrolysis apply across macromolecules; monomer to polymer building blocks depend on glycosidic linkages.
  • Quick takeaways for review:
    • Monomer: monosaccharide; Polymer: polysaccharide; Linkage: glycosidic; Major energy storage polymers: starch, glycogen; Structural polymers: cellulose, chitin.

Nucleic Acids

  • Monomer: nucleotide; components are a sugar (pentose), a phosphate group, and a nitrogenous base.
    • Phosphate group: hydrophilic, polar; acidic (can release H+ in solution).
    • Sugar: a pentose; differences define RNA vs DNA.
    • Nitrogenous base: attached to sugar; base types include purines (two rings) and pyrimidines (one ring).
  • Differences between RNA and DNA:
    • RNA uses ribose (has an extra 2′-OH group); DNA uses deoxyribose (lacks that 2′-OH).
    • RNA contains uracil (U); DNA contains thymine (T).
  • Nitrogenous bases:
    • Purines: adenine (A), guanine (G) – two rings.
    • Pyrimidines: cytosine (C), thymine (T, only DNA), uracil (U, only RNA).
  • Polymer: nucleic acids; monomers are nucleotides; polymers are DNA and RNA.
  • Linkages and directionality:
    • Backbone linked by phosphodiester bonds; linkage occurs between the