What is the monomer unit of protein? Give one example of such a monomer which contains sulphur. Write its zwitterionic form.

Explanation

The monomer unit of proteins is `alpha`-amino acid. An `alpha`-amino acid containing sulphur is cysteine.
`H_(2)N - underset(underset(underset("Cysteine")(CH_(2)SH))(|))(CH) - COOH hArr H_(3) overset(oplus)(N) - underset(underset(underset("Zwitterionic form")(CH_(2)SH))(|))(CH) - COO^(Θ)`