Part 1 of Essay
have played a major role in our society thanks to Sir Alexander Fleming's careful observations in 1928. Without it, many lives would be in danger due to infectious diseases. Antibiotics are chemical substances produced by various species of microorganisms and other living systems that are capable in small concentrat ....

Part 2 of Essay
.... including some that were once life-threatening. How Antibiotics Work ? Antibiotics can be bacteriostatic (bacteria stopped from multiplying) or bactericidal (bacteria killed). To perform either of these functions, antibiotics must be brought into contact with the bacteria. It is believed that antibiotics interfere with the surface of bacteria cells, causing a change in their ability to reproduce. Testing the action of an antibiotic in the laboratory shows how much exposure to the drug is necess ....