AP Bio Functional Groups

Hydroxyl

• –OH

  • Organic compounds with OH = alcohols 

  • Polar, hydrophilic and hydrogen bonding 

  • names typically end in -ol

    • Ex: ethanol

Carbonyl

• C=O 

  • O double bonded to C

    • If C=O at end molecule = aldehyde

    • If C=O in middle of molecule = ketone

  • Polar, hydrophilic and hydrogen bonding 

Carboxyl/Carboxylic Acid 

• –COOH 

  • C double bonded to O and single bonded to OH group

  • Polar, hydrophilic, acidic and hydrogen bonding 

    • Compounds with COOH =  organic acid

      • Fatty acids

      • Amino acids

Amino or Amine

• -NH₂  

  • N attached to 2 H

    • Compounds with NH₂ = amines

      • amino acids

  • Polar, hydrophilic, basic and hydrogen bonding 

    • Picks up H⁺ from solution

Sulfhydryl 

• –SH 

  • S bonded to H

    • compounds with SH = thiols

    • Polar, hydrophilic and hydrogen bonding 

    • SH groups stabilize the structure of proteins

Phosphate 

• –PO₄^2-

  • P bound to 4 O 

    • Connects to C through an O

    • Polar, hydrophilic and hydrogen bonding 

    • lots of O = lots of negative charge

      • Highly reactive

    • transfers energy between organic molecules 

      • ATP, GTP, etc.

Methyl Group

• —CH₃

  • central carbon atom bonded to three hydrogen atoms

  • The functional group itself is typically unreactive, even in the presence of very strong acids or bases

  • Hydrophobicity—methyl groups do not mix with water and are classified as nonpolar molecules because each carbon-hydrogen covalent bond is equally pulling electrons from the center.