no penicillin is a secondary metabolite,because secondary metabolite are compounds that use to kill other bacteria eg enzymes , antibiotics.etc

primary

primary

Metabolites are the intermediates and products of metabolism. The term metabolite is usually restricted to small molecules. A primary metabolite is directly involved in normal growth, development, and reproduction. A secondary metabolite is not directly involved in those processes, but usually has an important ecological function that means secondary metabolite usually is not that important for the organism and if this secondary meatbolite is not present it would not harm the organism.Now the examples for ur further help primary metabolites-- enzymes certain proteins .Secondary metabolite---- antibiotics, pigments etc

pollen contain large no of primary and secondary metabolite and that metabolite are known for defence properties / mechanism

therefore pollen having antimicrobial properties.