Edexcel iGCSE Biology-4.39 Antibiotic Resistance- Study Notes- New Syllabus
Edexcel iGCSE Biology-4.39 Antibiotic Resistance- Study Notes- New syllabus
Edexcel iGCSE Biology-4.39 Antibiotic Resistance- Study Notes -Edexcel iGCSE Biology – per latest Syllabus.
Key Concepts:
4.39 understand how resistance to antibiotics can increase in bacterial populations, and appreciate how such an increase can lead to infections being difficult to control
Antibiotic Resistance in Bacteria
🔹 Introduction
Antibiotics = drugs that kill bacteria or stop their growth.
Some bacteria survive due to resistance genes and multiply.
Over time, resistant bacteria dominate → infections become harder to treat.
📌 Key Points
- Variation exists: Random mutations in bacterial DNA → some bacteria resistant.
- Selection pressure: Antibiotics kill susceptible bacteria → resistant survive.
- Rapid reproduction: Resistant bacteria divide quickly → dominate population.
- Consequences: Infections harder to control, standard antibiotics may fail → superbugs.
- Prevention/Control: Avoid overuse, complete prescribed courses, maintain hygiene.
🧬 Example:
MRSA (Methicillin-resistant Staphylococcus aureus) → resistant to common antibiotics, difficult to treat in hospitals.
📊 Summary Table
| Step | Explanation | Example |
|---|---|---|
| Variation | Some bacteria resistant due to mutation | Small fraction resistant |
| Selection | Antibiotics kill susceptible bacteria | Resistant survive |
| Reproduction | Resistant bacteria multiply quickly | Population dominated by resistant |
| Effect | Infections harder to treat | MRSA infection |
📝 Quick Recap
Random mutation → some bacteria resistant.
Antibiotic use → kills susceptible, resistant survive.
Rapid reproduction → resistant strains dominate.
Result → infections harder to control, superbugs can appear.
Prevention → responsible antibiotic use + hygiene.