Antibiotics and painkillers (AQA GCSE Biology Combined Science): Revision Notes
Antibiotics and painkillers
What are painkillers and antibiotics?
Painkillers are medicines that help reduce the uncomfortable feelings caused by illness, like headaches or fever. However, they don't actually get rid of the germs causing the disease - they just make you feel better whilst your body fights the infection.
Antibiotics are completely different. These medicines actually destroy harmful bacteria that have gotten inside your body and are making you ill.
The key difference is that painkillers only treat symptoms, while antibiotics actively fight the cause of bacterial infections by killing the bacteria themselves.
How antibiotics work
Antibiotics are powerful medicines that can save lives by killing dangerous bacteria. Here's what you need to know:
- They only work against bacterial infections, not viral ones
- Different types of bacteria need different antibiotics to kill them
- Doctors must choose the right antibiotic for each specific bacterial infection
- Before antibiotics were discovered, many people died from bacterial diseases that we can easily treat today
Example: Penicillin's Impact
Penicillin is a famous example of an antibiotic. It was one of the first antibiotics discovered and has helped millions of people recover from bacterial infections. Before penicillin was available, simple bacterial infections could be life-threatening.
The problem of antibiotic resistance
Unfortunately, some bacteria have become much harder to treat. This happens when bacteria develop antibiotic resistance.
How resistance develops
When antibiotics are used, most bacteria die. But sometimes a few bacteria survive because they have slightly different characteristics. These surviving bacteria can then multiply and create a whole population of bacteria that the antibiotic cannot kill.
MRSA is a well-known example of resistant bacteria. This strain has developed resistance to several different antibiotics, making infections much harder to treat.
Why this is dangerous
The development of antibiotic resistance poses serious risks to public health:
- If bacteria become resistant to all available antibiotics, infections can spread quickly
- This could lead to epidemics where many people become seriously ill
- New antibiotics take years to develop and test
This process is an example of natural selection - the bacteria best suited to surviving the antibiotic treatment are the ones that reproduce and pass on their characteristics.
Why antibiotics don't work on viruses
Viruses cause diseases like measles, colds, and flu. However, antibiotics are completely useless against viral infections.
Why Antibiotics Can't Treat Viruses:
- Viruses work very differently from bacteria
- They live inside the cells of your body and use your cells to reproduce
- Antibiotics that kill viruses would also damage your healthy body cells
Creating antiviral medicines is extremely difficult because scientists need to find ways to stop viruses without harming the human cells they live inside.
Key Points to Remember:
- Painkillers treat symptoms but don't kill the germs causing disease
- Antibiotics kill bacteria but have no effect on viruses
- Antibiotic resistance develops when bacteria survive antibiotic treatment and multiply
- MRSA is an example of dangerous antibiotic-resistant bacteria
- Viral infections like measles cannot be treated with antibiotics
- Natural selection explains how antibiotic-resistant bacteria develop and spread