MRSA and C. difficile are resistant bacterial strains which cause life-threatening infections in hospitals. Explain how MRSA/ C. difficile could arise from non-resistant bacteria. [6 marks]
Natural SelectionCompetition for survival between bacterial colonies/ Selection pressure is survivalVariation between colonies linking to phenotype of resistanceSpontaneous mutation produces antibiotic resistance gene/alleleAntibiotic resistance gene is advantageousThose bacteria with the gene survive and reproduce/ Survival of the fittestOffspring inherit gene and so express resistance phenotypeOver time/ after many generations, this process repeats until most of the bacteria in the population are resistantEach point is worth 1 mark. Must have 2,4,6,7 to score full marks, if not 4 marks max.
IC
Related Biology GCSE answers
All answers ▸How does the heart pump oxygen around the body?
Draw a punnet square between two carriers of cystic fibrosis and from this, work out the odds of their child being affected with CF.
What are the fundamental differences between a cell membrane and a cell wall?
Q4: Some small organisms do not have a specialised gas exchange system like humans. Instead they absorb oxygen through their skin. What is this process called? • Transpiration • Respiration • Diffusion • Photosynthesis