there has been a lot of recent work delving into the biochemically active species.
It appears that acetaminophen is hydrolysed to p-aminophenol (the same as p-hydroxyanline) which is subsequently acylated with a long chain fatty acid. In the brain, it is metabolized by the enzyme Fatty Acid Amide Hydrolase (FAAH); an enzyme under intense study both at Merck and in the laboratory of Benjamin Cravatt. it's probably beyond the scope of a highschool class.... but for everyone else out there..give it a look-see..
You can probably find ALL the information you ever wanted to know for your class on wikipedia... it appears you should be interested in it's inhibition of a new isoform of cyclooxygenase COX-3,