When a cell forms an amino acid by adding an amine group derived from ammonia to a precursor metabolite, this process is called?

The process of adding an amine group to any organic molecule is known as amination. The aminase enzymes catalyze these processes. So, the creation of any amine group is amination. The cells of the body forms amino acid when an amine group is added to amino acid which is derived from the ammonia.

Hence, the correct answer is 'amination'.