Key term
OCR GCSE Biology A J247
Cell Level Systems
Topic overviewMicroscopy, and sub-cellular structuresDNA structure: polymer, double helix and nucleotidesEnzyme action, and investigating enzymesCellular respiration as an exothermic processAerobic and anaerobic respiration comparedSynthesis and breakdown of carbohydrates, proteins and lipidsPhotosynthesis: producers and the processPhotosynthesis as endothermic, and investigating itLimiting factors in photosynthesis
Community Level Systems
Genes, Inheritance and Selection
Topic overviewGenetic terms, and the genomeGenome, environment and mutationsAsexual and sexual reproduction comparedHaploid, diploid and meiosisSingle gene inheritance and Punnett squaresSex determination, multiple genes and Mendel's workVariation within a population, and classificationNatural selection and evolutionEvidence for evolution, and the work of Darwin and Wallace
Global Challenges
Topic overviewField investigations, and human impact on ecosystemsMaintaining biodiversity, monitoring conservation and ecotourismFood security, agricultural and biotechnological solutionsSelective breeding and genetic engineeringHealth, disease, and types of diseaseInteractions between diseases, and how they spreadReducing the spread of disease, and named examplesPhysical and chemical plant defencesWhite blood cells, antibodies and plateletsNon-specific defences and the immune systemVaccines, medicines and aseptic techniqueDeveloping new medicines, and non-communicable diseaseTreating cardiovascular disease, and lifestyle factorsCancer, and the use of stem cells in medicineGene technology in medicine, and the human genome
Organism Level Systems
Topic overviewThe nervous system and coordinated responsesThe reflex arcThe eye and its common defectsThe structure and function of the brainHormones and the endocrine glandsHormones in reproduction and the menstrual cycleMethods of contraceptionTropisms, auxin and the roles of plant hormonesHomeostasis, and the skin in temperature controlInsulin and the control of blood glucoseType 1 and type 2 diabetesOsmotic changes in body fluids, and the kidneysKidney structure and the parts of the tubule
Scaling Up
Topic overviewDiffusion, osmosis and active transportMitosis, the cell cycle and cell differentiationStem cells in animals and meristems in plantsSurface area to volume ratio and exchange surfacesThe circulatory system, the heart and blood vesselsRed blood cells and plasmaRoot hair cells, transpiration and translocationXylem and phloemFactors affecting water uptake, and the potometer
Global Challenges
Maintaining biodiversity, monitoring conservation and ecotourism
- 3 things to know
- Paper 2
Overview
The benefits of high biodiversity to people and why it makes an ecosystem stable, why international conservation agreements are hard to reach, why conservation schemes must be monitored and why that is difficult, what ecotourism is, and how it can both conserve and damage a habitat.
What you need to know
Answer each one before you reveal it.
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Key term
Explain why high biodiversity makes an ecosystem more stable.
Key term
Why is it difficult to reach international agreements on conservation?
Questions from this subtopic
Each one with the model answer underneath.
- 1
Give two benefits to people of maintaining high biodiversity.
Model answer
A wide range of species provides food, medicines and materials, and stable ecosystems continue to supply clean water, pollination and fertile soil.
- 2
Explain why high biodiversity makes an ecosystem more stable.
Model answer
Many species carry out similar roles, so if one declines others can replace it and the ecosystem continues to function.
- 3
Why is it difficult to reach international agreements on conservation?
Model answer
Countries have different priorities and levels of wealth, and a government may be unwilling to limit farming, logging or industry that its economy depends on.
- 4
Why is monitoring essential once a conservation scheme has begun?
Model answer
Without repeated surveys there is no evidence of whether the population is recovering, so the scheme cannot be judged or improved.
- 5
Give two reasons why monitoring a conservation scheme is hard to do well.
Model answer
Surveys of large or remote areas are expensive and need trained staff, and populations must be counted over many years before a trend is clear.
- 6
What is ecotourism?
Model answer
Tourism that lets visitors see wildlife in its natural habitat while limiting damage to that habitat and returning money to local people.
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