PMT amides, amino acids and chirality

• What are the two functional groups of amino acids?

  NH2 and COOH

  
• What are the names of the two functional groups of amino acids?

  Amine and carboxylic acid
• What is the general formula for α-amino acids?

  R-CH(NH2)-COOH

  
• Are α-amino acids chiral? Why?

  Yes, one carbon has 4 different substituents
• What is the exception to the chirality of α-amino acids?

  Glycine, where R = H
• Define a zwitterion.

  Ions with both positive and negative charge
• How do zwitterions occur in amino acids?

  COOH is deprotonated and NH2 is protonated
• What happens to amino acids in acidic conditions?

  Gains a proton on NH2 group
• What happens to amino acids in alkaline conditions?

  Loses a proton from COOH group
• What is the peptide linkage?

  -CONH-

  
• What are the structures of primary and secondary amides?

  • Primary amide: RCONH2
  • Secondary amide: R1R2C(=O)NH

  
• What property must a carbon atom have for optical isomerism?

  4 different substituents attached to one carbon
• What are the similarities and differences between two optical isomers?

  • Similarities: Same atoms and bonds
  • Differences: Non-superimposable mirror images
  • Rotate plane polarized light in different directions
• What word describes optically active molecules?

  Chiral
• Draw both enantiomers of a chiral molecule.

  • Draw the structure of lactic acid and its mirror image.