Activities and lesson plan notes for teachers on antibiotics and how antibiotic-resistant bacteria arise. Research and development to create new medicines to beat bacteria involves testing large numbers of chemical compounds to look at their biological activity. Decisions have to be made to pick which should be taken on to further development and production. It can be relatively quick and easy to obtain some key experimental results on large numbers of compounds using isolated enzymes or cells. However other tests that involve the use of animals and human patients must only be carried out on a selected small number of compounds.