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
Land use, deforestation and global warming
- 3 things to know
- Paper 2
Overview
Land lost to building, quarrying, farming and waste, peat bog destruction and the carbon dioxide it releases, tropical deforestation for cattle, rice and biofuels, carbon dioxide and methane in global warming, and its effects on species distribution and sea levels.
What you need to know
Answer each one before you reveal it.
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Key term
Why are peat bogs dug up?
Key term
Explain how destroying a peat bog reduces biodiversity.
Questions from this subtopic
Each one with the model answer underneath.
- 1
Name four human activities that reduce the amount of land available to other animals and plants.
Model answer
Building, quarrying, farming and dumping waste.
- 2
Explain why reducing the land available to wild species reduces biodiversity.
Model answer
Habitats are destroyed, so the species living there lose their food and shelter and their numbers fall.
- 3
Why are peat bogs dug up?
Model answer
The peat is used to make compost for gardens.
- 4
Explain how destroying a peat bog reduces biodiversity.
Model answer
The area of that habitat is reduced, so the plant, animal and microorganism species that live only in peat bogs decline.
- 5
Describe how the destruction of peat adds carbon dioxide to the atmosphere.
Model answer
Once removed the peat decays or is burned, and both of these release carbon dioxide.
- 6
Explain why an undisturbed peat bog acts as a store of carbon.
Model answer
Dead plant material builds up in waterlogged conditions with little oxygen and does not fully decay, so its carbon stays locked in the peat.
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