Cellulose is a 

Cellulose is a a polysaccharide and secondary metabolite. It is polymer of beta glucose subunits linked by glycosidic linkages. It is the chief component of primary cell wall of a plant cell.

Terpenoid,lectins and drugs are secondary metabolites exclusively. Secondary metabolites are those compounds produced as a byproducts of metabolism. Many of them are useful to human welfare.

Terpenoids : A class of naturally occurring diverse group of lipids showing anti microbial properties. 

Lecitns: Proteins that bind to carbohydrates specifically. They are produced as as part of defense mechanism in plants.

Drugs: Some secondary metabolites are useful as drugs.Example Vinblastin, curcumin etc.