GCSE BIOLOGY REVISION: INFECTION AND RESPONSE
Please note: Text in bold is what the AQA GCSE biology specification requires an understanding of.
Antibiotics and painkillers
Students should be able to explain the use of antibiotics and other medicines in treating disease. Antibiotics, such as penicillin, are medicines that help to cure bacterial disease by killing infective bacteria inside the body. It is important that specific bacteria should be treated by specific antibiotics.
The use of antibiotics has greatly reduced deaths from infectious bacterial diseases. However, the emergence of strains resistant to antibiotics is of great concern.
Antibiotics cannot kill viral pathogens. Painkillers and other medicines are used to treat the symptoms of disease but do not kill pathogens. It is difficult to develop drugs that kill viruses without also damaging the body’s tissues.
Previously, we discussed the definitions of painkillers and antibiotics and what they are used for.
This was the first antibiotic to be discovered by Alexander Fleming in 1928. Fleming recognised that the naturally occurring Penicillium mould killed the bacteria he had left inside a Petri dish.
How antibiotics work: They damage the bacterial cells without damaging the host cells. They are highly useful as they are able to cure many bacterial diseases that would have previously cause significant numbers of deaths. They have been highly influential on the world’s health and death rate.
Viral diseases cannot be treated using antibiotics. This is due to the fact they reproduce inside of cells and therefore must be treated with antiviral drugs. Otherwise we run the risk of damaging host cells to try to kill the virus. Antiviral drugs slow down the development of viruses. Viruses change their antigens quickly and so new drugs need to be generated regularly.
After antibiotic discovery, they had been increasingly used. This causes some problems.
The problems with antibiotic use has led to them becoming less effective, this is due to:
Failure to complete the fully prescribed course given by a doctor
The use of antibiotic treatment in farming
This can cause a reduction in the effectiveness and increases the incidence of antibiotic resistance. When antibiotic resistance occurs, the antibiotic is no longer effective on curing the bacterial infection so a new antibiotic needs to be developed. Making new antibiotics is highly time-consuming and expensive.
Superbugs- strains of bacteria that has become resistant to antibiotic drugs
When we feel ill, we all want to feel better as quickly as possible and do not want to risk the chance of the symptoms getting worse. We head to the doctors expecting to be prescribed antibiotics. Doctors will turn away patients with viral infections, suggesting other ways to feel better. They will only give antibiotics when it is a bacterial infection, as if not the treatment is ineffective and unnecessary.
Failing to complete the course
Doctors will always tell us to finish the course we have been prescribed, even if we feel like we are better. This ensures that all bacteria are killed. If some bacteria survive, this gives rise to the opportunity for mutation and production of resistant strains. Stopping the treatment before you are meant to is potentially harmful as resistant strains of bacteria can reproduce quickly, spreading the resistance.