Apex learning:

Antibiotics destroy a bacterial infection by disabling ribosomes in the bacteria. Eukaryotic cells contain mitochondria that themselves contain ribosomes while bacterial cells have no organelles and thus have uncontained ribosomes. How do chemists use this fact to create antibiotics that can destroy a bacterial infection without harming human cells?

Different antibiotics work differently from each other, some attack bacterial cell wall, some attack proteins, some attack ribosomes and some attack DNA replication machinery.

Antibiotics that attack the ribosomes such as 'tetracycline' actualy inhibit the bacteria to grow by attacking their protein synthesis. Protein synthesis is accomplished in ribosomes, tetracycline cross the bacterial membrane and enter cytoplasm from there i binds on a single specific site on the ribosomes which result in the halting of RNA interaction that stops protein synthesis or extension. In humans, the accumulation of such antibiotics is not to such an extent that it damages the cell machinery.