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
Genetics
Monohybrid crosses and sex determination
- 3 things to know
- Paper 1
Overview
Monohybrid inheritance and Punnett squares, the ratios from heterozygous and homozygous crosses, reading a family pedigree, and how the X and Y chromosomes decide sex.
What you need to know
Answer each one before you reveal it.
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Key term
Two heterozygous parents are crossed for a characteristic controlled by one gene. What ratio of phenotypes is expected in the offspring?
Key term
A heterozygous parent is crossed with a homozygous recessive parent. What ratio of phenotypes is expected?
Questions from this subtopic
Each one with the model answer underneath.
- 1
What is monohybrid inheritance?
Model answer
It is the inheritance of a single characteristic controlled by one gene.
- 2
What does a Punnett square show?
Model answer
It shows all the possible combinations of alleles in the offspring of a particular cross.
- 3
What is written along the top and down the side of a Punnett square?
Model answer
The alleles carried by the gametes of each of the two parents.
- 4
Two heterozygous parents are crossed for a characteristic controlled by one gene. What ratio of phenotypes is expected in the offspring?
Model answer
Three offspring showing the dominant characteristic to one showing the recessive characteristic.
- 5
A heterozygous parent is crossed with a homozygous recessive parent. What ratio of phenotypes is expected?
Model answer
A 1:1 ratio of the dominant characteristic to the recessive characteristic.
- 6
A homozygous dominant parent is crossed with a homozygous recessive parent. Describe the genotypes and phenotypes of the offspring.
Model answer
All the offspring are heterozygous and all show the dominant characteristic.
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