Phrasal verbs act on /upon (=to take action because you have been given information, advice, or orders): I was acting on the instructions of senior managers.
on (= affect): This medicine only acts on infected tissue.
Act out (= perform something through physical actions and gestures): We will act out the story on stage.
out (= express your feelings through your behavior): Please try also not to act out your anger.
Act up (= behave badly): Our children act up from time to time.
up (= operate badly): This car didn’t act up in cold weather so far.