cysteine vs amino acid

cysteine and amino acid both are nouns.

Word	Noun	Adjective	Verb	Adverb
cysteine	Yes	No	No	No
amino acid	Yes	No	No	No

As nouns, amino acid is a hypernym of cysteine; that is, amino acid is a word with a broader meaning than cysteine:

cysteine: an amino acid containing sulfur that is found in most proteins; oxidizes on exposure to air to form cystine
amino acid: organic compounds containing an amino group and a carboxylic acid group

Other hypernyms of cysteine include aminoalkanoic acid.

cysteine (noun)	amino acid (noun)
an amino acid containing sulfur that is found in most proteins; oxidizes on exposure to air to form cystine	organic compounds containing an amino group and a carboxylic acid group