This exam focus covers Exam Focus within Antibiotics and Drug Resistance for GCSE Biology. Antibiotic function, bacterial resistance evolution, responsible use, global health impact It is section 17 of 19 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
Topic position
Section 17 of 19
Practice
20 questions
Recall
24 flashcards
Exam Focus
Very Frequently ExaminedAntibiotic resistance is one of the most consistently examined topics in AQA GCSE Biology. Natural selection questions and required practical questions both appear regularly.
- Natural selection mechanism (4-5 marks): Random mutation → resistance gene present in a few bacteria → antibiotic kills non-resistant → resistant survive → reproduce → pass on resistance → population dominated by resistant bacteria. Every step is required for full marks. The word "mutation" must appear.
- Why not use antibiotics for viral infections (2 marks): Antibiotics target bacterial structures (cell walls, ribosomes). Viruses do not have these structures. Therefore antibiotics have no target and are ineffective. Also: unnecessary use accelerates resistance.
- Disc diffusion practical (3-4 marks): Measure zone of inhibition, compare sizes, link to antibiotic effectiveness. Know variables, know why 25°C is used, know what a control shows.
- Evaluating measures to reduce resistance (4 marks): Complete antibiotic courses, prescribe only for bacterial infections, reduce agricultural use, develop new antibiotics, better diagnostic tests. For each, explain HOW it reduces resistance (reduces selection pressure, prevents resistant strains surviving, etc.).
Common mark losses: Saying the person becomes resistant (it is the bacteria, not the person). Saying bacteria "learn" to resist (it is random mutation + selection). Not including the word "mutation" in natural selection answers. Forgetting that large zone = more effective (not the other way around).