First 169 words of the document:
General formula: RCH(NH2)COOH
In acidic solution: the NH2 group ionises as NH3+
In alkaline solution: the COOH group ionises as COO
At intermediate values of pH: a zwitterion forms
Dipolar (has positive and negative charges in different parts of the
In solution, the pH at which the concentration of the zwitterion is
highest is called the isoelectric point.
The ability of amino acids to form zwitterions confers the following properties:
Water-soluble can form hydrogen bonds.
Crystalline solids with high melting point forms ionic bonds between positive and
negative ions of the zwitterion.
Peptide bonds are the bonds between amino acids.
The formation of a peptide bond is a condensation reaction; water is
Peptide bonds are the same as amide bonds; they're called peptide
bonds when linking two amino acids.
The formation of a dipeptide from alanine and glycine:
Formation of a polypeptide: