Key term
AQA GCSE Combined Science Biology 8464
Bioenergetics
Cell Biology
Topic overviewEukaryotes and prokaryotesAnimal and plant cellsCell specialisation and differentiationMicroscopyChromosomes, mitosis and the cell cycleStem cells in embryos, adults and meristemsTherapeutic cloning, its risks, and cloning plantsDiffusion and the factors affecting its rateSurface area to volume ratio and exchange surfacesOsmosisActive transport
Ecology
Topic overviewLevels of organisation in an ecosystem, and what organisms needCompetition, interdependence and stable communitiesAbiotic factorsBiotic factorsAdaptationsProducers, food chains and sampling with quadrats and transectsPredators, prey and measuring population sizeHow materials are cycledWaste management and biodiversityLand use, deforestation and global warmingMaintaining biodiversity
Homeostasis and Response
Infection and Response
Inheritance, Variation and Evolution
Topic overviewSexual and asexual reproductionMeiosisDNA and the genomeGenetic terms, dominant and recessive allelesPunnett squares, probability and genetic crossesInherited disorders and sex determinationVariationEvolutionSelective breedingWhat genetic engineering is, and what it is used forGM crops, their risks, and the steps of the processEvidence for evolution, and extinctionFossilsResistant bacteriaClassification of living organisms
Organisation
Topic overviewLevels of organisation, and how enzymes workAmylase, proteases and lipasesBile, food tests and the effect of pH on amylaseThe heart, the lungs and double circulationThe pacemaker, the blood vessels and the bloodCoronary heart disease: a non-communicable diseaseHealth issuesRisk factors and causal mechanisms in diseaseSampling, correlation and interpreting risk dataCancerPlant tissues, and transpiration and its rateRoot hair cells, xylem, phloem and stomata
Inheritance, Variation and Evolution
Resistant bacteria
- 3 things to know
- Biology Paper 2
Overview
Why bacteria evolve rapidly, how mutation and antibiotic use produce and spread resistant strains such as MRSA, slowing resistance by limiting prescriptions, completing courses and restricting farm use, and the cost and slowness of developing new antibiotics.
What you need to know
Answer each one before you reveal it.
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Key term
Why does the population of a resistant strain rise?
Key term
Give two reasons a resistant strain spreads quickly through a population of people.
Questions from this subtopic
Each one with the model answer underneath.
- 1
Why can bacteria evolve rapidly?
Model answer
They reproduce at a very fast rate.
- 2
A population of bacteria doubles every 20 minutes. Explain why this makes resistance a serious problem.
Model answer
Huge numbers are produced in a short time, so mutations arise often and a resistant strain can build up very quickly.
- 3
What produces new strains of a bacterial pathogen?
Model answer
Mutations.
- 4
What happens to a resistant strain of bacteria when an antibiotic is used?
Model answer
It is not killed, so it survives and reproduces.
- 5
Why does the population of a resistant strain rise?
Model answer
The resistant bacteria survive treatment and reproduce, while the others are killed.
- 6
Give two reasons a resistant strain spreads quickly through a population of people.
Model answer
People are not immune to the new strain and there is no effective treatment for it.
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