Antibiotics
- Antibiotics are drugs that inhibit the growth of microorganisms
- Most antibiotics kill or stop the growth of bacteria (prokaryotes) but do not harm the cells of the infected organism
- This is because they block specific processes that occur in prokaryotic cells but do not have the same effect on eukaryotic cells
- Processes that might be targeted include:
- Transcription
- Translation
- DNA replication
- Ribosome function
- Cell wall formation
- Some antibiotics are derived from living organisms such as saprotrophic fungi
- Penicillin is produced by certain fungi in the genus Penicillium
- When growing in the wild the antimicrobial secretions of the fungus helps it to compete by killing nearby saprotrophic bacteria
- Antibiotics can also be made synthetically (in a laboratory)
How penicillin works
- Penicillin is not effective against all bacteria (eg. tuberculosis) because the bacteria may have:
- Thicker cell walls which reduce permeability
- Enzymes which breakdown penicillin
- There are many different examples of antibiotics which are effective against a range of bacterial diseases