Serine is an amino acid containing a hydroxy group. It is effectively hydroxy-alanine.
Like all amino acids, it has an amino group (-NH2)- blue with 2 white balls - at one end, and a carboxylic acid group (-COOH) - grey, connected to red, and red and white - at the other end. Between these is the
α- (alpha) carbon
to which the 'R' group (and a single -H atom) is