Key term
AQA GCSE Biology 8461
Bioenergetics
Cell Biology
Topic overviewEukaryotes and prokaryotesAnimal and plant cellsCell specialisation and differentiationMicroscopyGrowing bacteria and aseptic techniqueCalculating bacterial growth, and testing antiseptics and antibioticsChromosomes, 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 cycledDecompositionWaste management and biodiversityLand use, deforestation and global warmingMaintaining biodiversityTrophic levels and pyramids of biomassTransfer of biomassFactors affecting food securityFarming techniques and sustainable fisheriesRole of biotechnologyImpact of environmental change
Homeostasis and Response
Topic overviewHomeostasisThe nervous system and the reflex arcThe structure of the eye and accommodationMyopia, hyperopia and how they are correctedThe brain and the control of body temperatureHuman endocrine systemInsulin, glucagon and diabetesWater and ion loss, and the production of ureaThe kidneys, ADH and treating kidney failureHormones in human reproductionContraceptionThe use of hormones to treat infertilityNegative feedbackPlant hormones and their uses
Infection and Response
Topic overviewCommunicable (infectious) diseasesViral diseasesBacterial diseasesFungal and protist diseasesHuman defence systemsVaccinationAntibiotics and painkillersDiscovery and development of drugsProducing monoclonal antibodiesUses of monoclonal antibodiesDetection and identification of plant diseasesPlant defence responses
Inheritance, Variation and Evolution
Topic overviewSexual and asexual reproductionMeiosisAdvantages and disadvantages of sexual and asexual reproductionDNA and the genomeDNA as a polymer of four nucleotidesProtein synthesis and complementary base pairingMutations, protein shape and non-coding DNAGenetic 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 processCloningDarwin, Lamarck and the acceptance of evolutionSpeciationThe understanding of geneticsEvidence 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
Organisation
Sampling, correlation and interpreting risk data
- 3 things to know
- Paper 1
Overview
Why several factors interact to cause disease, large and representative samples with a comparison group, incidence and trend calculations, and correlation on a scatter diagram against a causal mechanism.
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
Give an example of several factors interacting to cause one disease.
Key term
Explain why it is difficult to prove that one particular factor causes a disease.
Questions from this subtopic
Each one with the model answer underneath.
- 1
Explain why two people exposed to the same risk factor may not both develop the disease.
Model answer
Most diseases result from several factors interacting, including inherited ones, so a single risk factor does not decide the outcome.
- 2
Give an example of several factors interacting to cause one disease.
Model answer
Cardiovascular disease can result from diet, lack of exercise, smoking and inherited factors acting together.
- 3
Explain why it is difficult to prove that one particular factor causes a disease.
Model answer
Several factors act at the same time, so the effect of the one being studied has to be separated from the rest.
- 4
Explain why a study of a risk factor should include a very large number of people.
Model answer
Small samples are easily distorted by chance, so a large sample gives a more reliable estimate of the real effect.
- 5
Why should a study of a risk factor also include people who are not exposed to it?
Model answer
Those people show what the rate of disease would be without the factor, so the two groups can be compared.
- 6
Suggest why a survey carried out in one workplace may give misleading data about a risk factor nationally.
Model answer
The sample is not representative, because the people share an age range, income and way of life unlike the wider population.
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