Of course there are amino acids that don't exist in plants, but they are not essential (i.e. can be synthesized in the human body and don't need to be taken fro

Of course there are amino acids that don't exist in plants, but they are not essential (i.e. can be synthesized in the human body and don't need to be taken from external sources). From first principles, it's possible because e.g. cows could make amino acids that are not found in plants, but those are not essential (I don't know if cows make any non essential amino acids that are not found in plants, this is just an example)