This lecture covers the importance of organic chemistry in everyday compounds, focusing on different classes of antibiotics. It explains the mode of action and examples of antibiotics such as Chloramphenicol, Penicillins, Cephalosporins, Sulfonamides, Aminoglycosides, Tetracyclines, Macrolides, Glycopeptides, Ansamycins, Quinolones, Streptogramins, Oxazolidinones, and Lipopeptides. The lecture also discusses the development of resistance to antibiotics and their impact on bacterial growth and reproduction.