Key term
Edexcel GCSE Biology 1BI0
Key Concepts in Biology
Topic overviewEukaryotic and prokaryotic cellsSpecialised cells and their adaptationsMicroscopes and magnification calculationsSize, scale and units in cell biologyEnzyme action and denaturationFactors affecting enzyme activityEnzymes in synthesis and digestion, and rate calculationsFood tests and the energy in foodDiffusion, osmosis and active transportOsmosis in potatoes and percentage change in mass
Cells and Control
Topic overviewMitosis and the cell cycleWhy mitosis matters: growth, repair and cancerGrowth, differentiation and percentile chartsStem cells and their use in medicineThe structure and function of the brainInvestigating and treating the brainNeurones, receptors and the reflex arcThe structure and function of the eyeEye defects and how they are corrected
Genetics
Topic overviewAsexual and sexual reproductionMeiosis and the formation of gametesDNA structure, genes and the genomeExtracting DNA from fruitProtein synthesis: transcription and translationGenetic variants in coding and non-coding DNAMendel's work and the inheritance of blood groupsAlleles, genotype and phenotypeMonohybrid crosses and sex determinationProbability and ratios from genetic crossesSex-linked disordersCauses of variation: genes and environmentThe Human Genome ProjectGenetic variation and the effects of mutation
Natural Selection and Genetic Modification
Topic overviewDarwin, Wallace and the theory of evolutionNatural selection and antibiotic resistanceFossil evidence for human evolutionStone tool evidence for human evolutionThe pentadactyl limb and the three domainsSelective breedingTissue cultureGenetic engineering and modern agricultureThe stages of genetic engineeringBenefits and risks of GM organisms
Health, Disease and the Development of Medicines
Topic overviewHealth, disease and susceptibilityPathogens and common infectionsHow pathogens spread, and the virus life cycleSexually transmitted infectionsHow plants defend themselves and how plant disease is detectedPhysical barriers and chemical defencesThe immune system, immunisation and herd immunityAntibiotics and developing new medicinesAseptic technique in culturing microorganismsTesting antiseptics and antibiotics on bacterial culturesMonoclonal antibodiesLifestyle factors and non-communicable diseaseTreatments for cardiovascular disease
Plant Structures and Their Functions
Topic overviewPhotosynthesis as an endothermic reactionLimiting factors in photosynthesisLight intensity and the rate of photosynthesisRoot hair cells, xylem and phloemTranspiration and translocationLeaf structure for photosynthesis and gas exchangeFactors affecting the rate of transpirationPlant adaptations to extreme environmentsPlant hormones and their commercial uses
Animal Coordination, Control and Homeostasis
Topic overviewHormones, endocrine glands and homeostasisAdrenalin, thyroxine and negative feedbackThe menstrual cycle and its hormonesHormonal and barrier contraceptionAssisted reproductive technology and IVFHomeostasis and thermoregulationControlling blood glucose, and type 1 diabetesType 2 diabetes and body massThe urinary system and the production of ureaThe nephron, filtration and the effect of ADHTreating kidney failure: dialysis and transplants
Exchange and Transport in Animals
Topic overviewWhy multicellular organisms need exchange surfacesAlveoli and gas exchangeRate of diffusion and Fick's lawThe blood and its componentsArteries, veins and capillariesThe heart and the circulatory systemCellular respiration as an exothermic reactionAerobic and anaerobic respiration comparedInvestigating the rate of respirationCardiac output, stroke volume and heart rate
Ecosystems and Material Cycles
Topic overviewLevels of organisation and interdependenceAbiotic and biotic factors in a communityParasitism and mutualismSampling with quadrats and transectsEstimating population size from field dataEnergy transfer between trophic levelsHuman impact on ecosystems and biodiversityFood securityThe carbon cycleThe water and nitrogen cyclesIndicator species and pollutionFactors affecting the rate of decompositionCalculating the rate of decay
Ecosystems and Material Cycles
Indicator species and pollution
- 3 things to know
- Paper 2
Overview
Indicator species, the bloodworms, sludgeworms, freshwater shrimps and stonefly nymphs that show polluted or clean water, lichens and blackspot fungus as indicators of sulfur dioxide in the air, and the advantages and limitations of using indicator species.
What you need to know
Answer each one before you reveal it.
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Key term
Name two invertebrates whose presence in a river indicates that the water is polluted.
Key term
Name two invertebrates found in clean, well-oxygenated fresh water.
Questions from this subtopic
Each one with the model answer underneath.
- 1
What is an indicator species?
Model answer
An indicator species is an organism whose presence or absence shows how polluted an environment is.
- 2
Name two invertebrates whose presence in a river indicates that the water is polluted.
Model answer
Bloodworms and sludgeworms.
- 3
Name two invertebrates found in clean, well-oxygenated fresh water.
Model answer
Freshwater shrimps and stonefly nymphs.
- 4
A sample from a stream contains many sludgeworms and no stonefly nymphs. What does this suggest about the water?
Model answer
The water is polluted and contains very little dissolved oxygen.
- 5
Explain why bloodworms survive in water where stonefly nymphs cannot.
Model answer
Bloodworms tolerate very low oxygen concentrations, whereas stonefly nymphs only survive in well-oxygenated water.
- 6
How can the lichens growing on trees and walls be used to judge air quality?
Model answer
A wide variety of lichens, especially bushy ones, indicates clean air, while their absence indicates air polluted with sulfur dioxide.
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