• Carbon is essential for all life → leads to diversity, forms cell structure, and is used to build all macromolecules
  • Diversity of organisms due to carbon’s ability to build long chains of itself, bond to lots of molecules & form a wide variety of compounds (chemical versatility) bcuz has 4 valence electrons
    • Form strong bonds with C, H, O, N
  • Organic compound includes carbon; Inorganic compound does not include carbon
  • Factors that determine an organic molecules’ properties
    • Carbon Backbone – central part of organic molecule, bonding sites of atoms that determines their structure (function/properties),
      • Rings, linear, branching, single/double bond: shape determines function
      • Carbon atoms bond to other carbon atoms to form very long carbon chains/skeleton
    • Functional Groups – branch off carbon backbone & determine chemical properties of an organic compound
      • In a reaction the backbone is unchanged & only functional groups react


  • Long chains of covalently bonded carbon and hydrogen
    • Come in many structures which determine properties: single, double, or triple bonds which makes it more rigid
  • Make up lipids and contains lots of energy (lots of bonds)
  • Nonpolar (Hydrophobic)
    • Only polar if has electronegative charge (O2, Su, F, N — electronegative atoms)


  • “Compounds with same formula but diff arrangement of atoms” = structure determines function
    • Structural: placement of carbons is diff which results in diff bonding functional groups and properties
    • Geometric: functional groups branching of backbone are diff caused by variations around carbon double bond
    • Cis: functional groups on same side
    • Trans: functional groups on opp side
  • Enantiomers/Stereoisomers: molecules are mirror images of each other bcuz of asymmetric carbon

Functional Groups Continued                                                                                                   

  • Affect structure and function
    • Ex: determine if amino acid is polar or nonpolar
  • All life does NOT require same elements
    • TRUE for amino acids which always have amino and carboxyl group


Functional Group Examples Characteristics
-OH       Hydroxyl Alcohols (ethanol, glycerol) Polar, hydrophilic
-COOH  Carboxyl

–          C double bonded to oxygen, single bond to OH

Amino acids, fatty acids Polar, hydrophilic, weak acid
-C=O    Carbonyl   acidic
-NH₂    Amino Group Amino acids Polar, hydrophilic, weak base
-PO₄    Phosphate DNA, ATP, phospholipids Polar, hydrophilic, acid
-CH₃    Methyl Fatty acids, oils, waxes Nonpolar, hydrophobic
-SH     Sulfhydryl -thiols Stabilize protein 3rd structure