Provided by diet, phenylalanine can be converted into another amino acid, tyrosine, in the body. Tyrosine is used to synthesize two key neurotransmitters that promote alertness: dopamine and norepinephrine.
It has 3 forms:
L-phenylalanine - most common, the form in which phenylalanine is incorporated into the body’s proteins;
Protists - members of an informal grouping of diverse eukaryotic organisms that are not animals, plants or fungi, and are grouped together for convenience, like algae or invertebrates. Besides their relatively simple levels of organization, protists do not necessarily have much in common.
Subdivisions of Protists
Protozoa the unicellular "animal-like" - Flagellata, Ciliophora, Amoeba, Sporozoans.
Protophyta the "plant-like" - mostly unicellular algae.
Molds the "fungus-like" - slime molds and water molds.