Good things to include might be where your molecule comes from (synthesis pathway? breakdown product? being eaten?), where it exists in the system (liver? brain? flagellum?), and where the described reaction takes place (membrane-bound? cytoplasmic? in the blood?). Statements based on references should be indicated in the text. Even if you cite everything properly, you will only get points for the parts of your submission that are in your own words. Pasting in someone else’s words does not mean you understand them. Write something of your own to show that you do.