Antibiotics Essay Research Paper Fact Sheet No — страница 3

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either kill already grown bacteria, or they inhibit the growth of growing bacteria. They accomplish this end in many different ways, some affect cell walls, some the cytoplasmic membrane, and some affect an enzyme involved in nucleic acid synthesis. Some affect only gram-positive or gram-negative bacteria, while some affect both. The antibiotic we worked with, Tetracycline, inhibits protein synthesis by binding to the ribosomes and preventing the tRNA from docking at the “A” site. This prevents protein synthesis and will kill the cell. Antibiotic Resistance: Resistance to antibiotics develops in bacteria in the following way. In many types of bacteria there are a small number of cells which contain genes that are resistant to certain antibiotics. When a small dose of

antibiotics is applied to a colony of bacteria, all the cells not resistant are killed or inhibited, while the resistant cells remain strong. The resistant cells then proceed to thrive and multiply, passing down their resistance to their offspring. In addition, these bacteria spread their resistant traits to other, previously non-resistant cells through the methods mentioned above (transformation and conjugation), thus eventually affecting the entire colony.