Cheese = Cytoplasm, the gloppy foundation that all the other stuff is stuck upon

Bacon strips = Endoplasmic Reticulum, the delivery pathways

Green bell peppers = Ribosomes, the little protein cooks

Pepperoni = Lysosomes, the cell trash men

Onion rings = Golgi Apparatus, shipping and packing facility

Sausage = the engine rooms (mitochondria)

Crust = Cell Membrane, the slice is covered by this

The center, which is a blob of mozzarella = Nucleus, which contains the DNA recipe!