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 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 fruitMendel's work and the inheritance of blood groupsAlleles, genotype and phenotypeMonohybrid crosses and sex determinationProbability and ratios from genetic crossesCauses 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 agricultureBenefits 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 themselvesPhysical barriers and chemical defencesThe immune system, immunisation and herd immunityAntibiotics and developing new medicinesAseptic technique in culturing microorganismsTesting antiseptics and antibiotics on bacterial culturesLifestyle 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, phototropism and gravitropism
Animal Coordination, Control and Homeostasis
Topic overviewHormones, endocrine glands and homeostasisThe menstrual cycle and its hormonesHormonal and barrier contraceptionHomeostasis and thermoregulationControlling blood glucose, and type 1 diabetesType 2 diabetes and body massThe urinary system and the production of ureaThe nephron, filtration and selective reabsorptionTreating 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 cyclesFactors affecting the rate of decompositionCalculating the rate of decay
Genetics
- 11 subtopics
- 33 things to know
- Paper 1
What Genetics covers
Genetics is examined in Paper 1, Biology 1. It covers asexual and sexual reproduction, meiosis, DNA structure, genes and the genome, extracting DNA from fruit, Mendel's work and the inheritance of blood groups, alleles, genotype and phenotype, monohybrid crosses, sex determination and probability, genetic and environmental variation, the Human Genome Project and mutation.
Where it is assessed
Paper 1
Biology 1: 1 hour 45 minutes, 100 marks, 50% of the GCSE.
Check the Pearson Edexcel specification ↗The 11 subtopics
Each one has its own page.
- Asexual and sexual reproductionAsexual reproduction producing clones, its advantages of needing no mate and reproducing rapidly and the risk its lack of variation brings, and how fertilisation in sexual reproduction produces variation that helps a population survive disease and changing conditions.Open →
- Meiosis and the formation of gametesWhere meiosis takes place, the four haploid daughter cells it makes with half the chromosome number, the 23 chromosomes in a human gamete, why gametes must be haploid for fertilisation, and how the random sharing of chromosomes makes gametes and children genetically different.Open →
- DNA structure, genes and the genomeDNA as a double helix polymer of nucleotides made of a sugar, a phosphate and one of four bases, complementary base pairing held by weak hydrogen bonds, genes as sections of DNA coding for proteins, the genome, and why people with the same genes can differ.Open →
- Extracting DNA from fruitExtracting DNA from fruit by mashing, adding detergent and salt, filtering and pouring on ice-cold ethanol, why the DNA comes out of solution as a white stringy layer, and why the mixture is stirred gently.Open →
- Mendel's work and the inheritance of blood groupsMendel's pea plant crosses, the 3:1 ratio, why his ideas were slow to be accepted, and the three ABO alleles, codominance and the blood groups they give.Open →
- Alleles, genotype and phenotypeAlleles and why individuals of a species differ, dominant and recessive alleles and how a recessive allele can be carried unseen, chromosomes and genes, homozygous and heterozygous, genotype and phenotype, gametes and zygotes, and why one phenotype can hide different genotypes.Open →
- Monohybrid crosses and sex determinationMonohybrid inheritance and Punnett squares, the ratios from heterozygous and homozygous crosses, reading a family pedigree, and how the X and Y chromosomes decide sex.Open →
- Probability and ratios from genetic crossesThe probabilities and percentages expected from heterozygous and homozygous recessive crosses, turning offspring counts into whole-number ratios, and why real results rarely match the prediction.Open →
- Causes of variation: genes and environmentCharacteristics controlled by many genes such as height and their continuous range, genetic variation from mutation and sexual reproduction, acquired characteristics and environmental variation, identical twins, and presenting variation with frequency tables, histograms, bar charts and the modal class.Open →
- The Human Genome ProjectThe aim and outcomes of the Human Genome Project, testing for inherited disorders and predicting disease risk, personalised medicine and new drug treatments, tracing human migration, and concerns about insurers, employers and knowing the risk of an untreatable disease.Open →
- Genetic variation and the effects of mutationExtensive genetic variation within a population, mutations as random changes in base sequence and the source of new variation, why most mutations have no effect on the phenotype, the rare ones that stop a protein working, and mutations that give an advantage.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Evaluation
Describe asexual reproduction and explain one advantage and the main disadvantage of reproducing that way.
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How many daughter cells are formed from one parent cell by meiosis?
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Why is fruit such as kiwi mashed at the start of extracting DNA from it?
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What did Mendel conclude was passed from parents to offspring?
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What is an allele?
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What is written along the top and down the side of a Punnett square?
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Two heterozygous parents are crossed. What is the probability that a child shows the recessive characteristic?
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Give an example of a human characteristic that is controlled by many genes.
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State one outcome of the Human Genome Project.
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What is the ultimate source of new genetic variation in a population?
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How many parents are involved in asexual reproduction?
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How does the chromosome number of a cell made by meiosis compare with that of the parent cell?
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What is the repeating unit from which the DNA polymer is built?
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Why is detergent added to the mashed fruit when extracting DNA?
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Mendel bred two pure-breeding pea plants with contrasting characteristics. What did he observe in the first generation?
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How many alleles of each gene does an individual normally have?
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Two heterozygous parents are crossed for a characteristic controlled by one gene. What ratio of phenotypes is expected in the offspring?
Numbers
Two heterozygous parents are crossed. What percentage of the offspring are expected to show the dominant characteristic?
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Explain why a simple genetic cross diagram cannot predict a person's height.
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Explain how knowing the position of a gene helps doctors test for an inherited disorder.
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What is a mutation?
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Explain how a rapid reproductive cycle benefits an organism that reproduces asexually.
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What is meant by a haploid cell?
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Describe the overall shape of a DNA molecule.
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Why is salt added to the mixture when extracting DNA from fruit?
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Explain why counting large numbers of offspring was important to Mendel's conclusions.
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What happens to the characteristic when an individual inherits two different alleles of a gene?
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A heterozygous parent is crossed with a homozygous recessive parent. What ratio of phenotypes is expected?
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Two heterozygous parents are crossed. What percentage of their children are expected to be heterozygous?
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Explain why brothers and sisters vary so widely in characteristics such as skin colour.
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Describe how the Human Genome Project can help predict a person's risk of disease.
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What effect do most mutations have on the phenotype?
Take Genetics further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Genotype vs Phenotype
Genotype: combination of alleles an organism has for a characteristic. Phenotype: observable characteristic the organism actually shows.
Homozygous vs Heterozygous
Homozygous: having two identical alleles of a particular gene. Heterozygous: having two different alleles of a particular gene.
Dominant allele vs Recessive allele
Dominant allele: version expressed in the characteristic even when only one copy is present. Recessive allele: version only expressed when two copies are present.
Questions from this topic
Each one with the model answer underneath.
- 1
How many parents are involved in asexual reproduction?
Model answer
Only one parent is involved in asexual reproduction.
- 2
How are offspring produced by asexual reproduction related to their parent genetically?
Model answer
They are genetically identical to the parent, so they are clones.
- 3
Explain why not needing a mate is an advantage of reproducing asexually.
Model answer
No time or energy is spent searching for a partner, so an isolated individual can still produce offspring.
- 4
Explain how a rapid reproductive cycle benefits an organism that reproduces asexually.
Model answer
Large numbers of offspring are produced quickly, so a favourable habitat can be colonised before competitors arrive.
- 5
Why is the lack of variation a disadvantage of asexual reproduction?
Model answer
All the offspring have the same alleles, so none of them is better suited to a change in conditions.
- 6
Explain why a new disease can wipe out an entire population of asexually produced organisms.
Model answer
Every individual is genetically identical, so if one is susceptible to the pathogen they all are.
What is inside Levo
Six ways to work the same material.
Genetics revision questions
- What does Genetics cover in Edexcel GCSE Biology?
- 11 subtopics: asexual and sexual reproduction, meiosis and the formation of gametes, dna structure, genes and the genome, extracting dna from fruit, mendel's work and the inheritance of blood groups, alleles, genotype and phenotype, monohybrid crosses and sex determination, probability and ratios from genetic crosses, causes of variation: genes and environment, the human genome project and genetic variation and the effects of mutation. Each one has its own page with questions and model answers.
- How is Genetics organised?
- By the Edexcel 1BI0 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Genetics, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
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