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 biotechnology
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 reproductionContraceptionPlant hormones and their uses
Infection and Response
Inheritance, Variation and Evolution
Topic overviewSexual and asexual reproductionMeiosisAdvantages and disadvantages of sexual and asexual reproductionDNA and the genomeDNA as a polymer of four nucleotidesGenetic 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
Ecology
Factors affecting food security
- 2 things to know
- Paper 2
Overview
What food security is, how birth rate, changing diets, pests, pathogens, drought, farming costs and conflict threaten it, sustainable food production, and why eating crops directly feeds more people than feeding them to animals.
What you need to know
Answer each one before you reveal it.
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Key term
Explain how changing diets in wealthier countries can threaten food security elsewhere.
Questions from this subtopic
Each one with the model answer underneath.
- 1
What is food security?
Model answer
Having enough food to feed a population.
- 2
Explain how an increasing birth rate threatens food security.
Model answer
More people must be fed from the same area of farmland, so there is less food available for each person.
- 3
Explain how changing diets in wealthier countries can threaten food security elsewhere.
Model answer
Scarce food resources are transported around the world to supply those diets instead of feeding the people who grow them.
- 4
How can a new pest threaten food security?
Model answer
It damages or destroys the crops, so the harvest is much smaller.
- 5
How can a new pathogen threaten food security?
Model answer
It causes disease in crops or farm animals, so less food is produced.
- 6
Give an example of an environmental change that threatens food production.
Model answer
The failure of the seasonal rains, which makes crops fail and can lead to widespread famine.
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