Antibiotics and Painkillers

This lesson covers antibiotics, painkillers and antibiotic resistance as required by the Edexcel GCSE Combined Science specification (1SC0). You need to understand the difference between antibiotics and painkillers, explain how antibiotic resistance develops (including MRSA), and know the significance of Alexander Fleming's discovery of penicillin.

---

What Are Antibiotics?

Antibiotics are medicines that kill bacteria or prevent them from reproducing. They are used to treat bacterial infections.

Key points about antibiotics:

• Antibiotics are specific — different antibiotics work against different types of bacteria.
• Antibiotics work by interfering with bacterial processes such as cell wall synthesis or protein production.
• Antibiotics do NOT work against viruses. This is because viruses reproduce inside host cells using the host's own machinery, so there is nothing for the antibiotic to target without damaging the host cell.

Feature	Antibiotics
Target	Bacteria
Mode of action	Kill bacteria or stop them reproducing
Do they kill viruses?	No
Example	Penicillin
Prescription required?	Yes (in the UK)