Oh. For all intensive purposes. Ampicillin, Ancillin, Amoxicillin, and Penicillin are BASICALLY the same. Not exactly. But they're all bactericidal.
They work basically inhibiting chemicals in the cell of the bacteria from rebuilding the cell wall and doing 1 of 2 things. The bacteria falls apart OR a white blood cell easily destroys it. (I really seriously love medicine)
But yes. They're all penicillin based drugs and for your purposes, penicillin and ampicillin are the essentially the same. In fact, they have the same unit dosage.