6.3 - C - Antibiotics
Antibiotics are chemical compounds that are able to slow or stop the growth of microbes. They do so by impeding the life process of prokaryotic cells, which gives the immune system time to respond to an infection. Processes that antibiotics target include:
It is important to note that in order to be effective, antibiotics do not target the host's cells. So, they only affect prokaryotic cells and not eukaryotic cells.
Since antibiotics target the metabolic processes of prokaryotic cells, they are unable to treat viral infections. Viruses are not living organisms and so have no metabolism for antibiotics to target.
Viruses infect host cells with their genetic information and rely on the cell's metabolism to reproduce. Instead of antibiotics, antiviral medications can be used to treat viral infections. These medications can target:
The first antibiotic, penicillin, was discovered by Alexander Fleming in the 1920's. Florey and Chain were Oxford researchers who wanted to determine whether the antibiotic could control bacterial growth in humans as opposed to on agar plates. To do this, they purposefully infected 8 mice with Streptococcus, a life-threatening infection.
As discussed in Topic 5.2 - D, bacteria populations can develop resistance to antibiotics through natural selection. Random mutations, can result in single bacteria that are able to defend against the mechanism of the antibiotic.
As shown in the diagram below, these resistant cells are able to reproduce and take over the population while the antibiotic kills those who do not have the mutation for resistance.
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