As I mentioned the 1945 Nobel Prize in Physiology or Medicine was awarded to Fleming , Chain and Florey "for the discovery of penicillin and its curative effect in various infectious diseases". The Nobel foundation maintain a nice website with biographies of all the winners plus their Nobel lectures and banquet speeches. In this case the presentation speech is a nice summary of the work and provides a bit more information than that provided in class.
It is hard to imagine the impact of penicillin in a world without antibiotics. Not only were many wound infections now easily treated but many other diseases could now be treated quickly and easily.