Key term
AQA GCSE Combined Science Biology 8464
Bioenergetics
Cell Biology
Topic overviewEukaryotes and prokaryotesAnimal and plant cellsCell specialisation and differentiationMicroscopyChromosomes, 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 cycledWaste management and biodiversityLand use, deforestation and global warmingMaintaining biodiversity
Homeostasis and Response
Infection and Response
Inheritance, Variation and Evolution
Topic overviewSexual and asexual reproductionMeiosisDNA and the genomeGenetic 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 processEvidence 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
Inheritance, Variation and Evolution
- 15 subtopics
- 45 things to know
- Biology Paper 2
What Inheritance, Variation and Evolution covers
Inheritance, Variation and Evolution is examined in Biology Paper 2. It covers sexual and asexual reproduction and meiosis; DNA and the genome; genetic terms, Punnett squares and genetic crosses; inherited disorders and sex determination; variation and evolution; selective breeding, genetic engineering and GM crops; evidence for evolution, extinction, fossils and resistant bacteria; and the classification of living organisms.
Where it is assessed
Biology Paper 2
Combined Science: Trilogy, Biology Paper 2: 1 hour 15 minutes, 70 marks, 16.7% of the qualification.
Check the AQA specification ↗The 15 subtopics
Each one has its own page.
- Sexual and asexual reproductionMitosis and meiosis, gametes in animals and flowering plants and their fusion at fertilisation, why sexual reproduction produces variation, and asexual reproduction from one parent by mitosis producing clones.Open →
- MeiosisHow meiosis halves the chromosome number and fertilisation restores it, where it happens, copying then two divisions giving four different gametes, and mitosis in the growing embryo.Open →
- DNA and the genomeNucleus, chromosome and gene by size, the double helix and DNA as a polymer, what a gene codes for, and what studying the human genome offers medicine and migration history.Open →
- Genetic terms, dominant and recessive allelesGametes, chromosomes, alleles, genotype and phenotype, characteristics controlled by a single gene, dominant and recessive alleles and when each is expressed, and homozygous and heterozygous organisms.Open →
- Punnett squares, probability and genetic crossesCharacteristics controlled by several genes, why a cross predicts only probabilities, ratios and percentages from 3:1 and 1:1 crosses, and worked crosses in mice, cats, peas and a recessive disorder.Open →
- Inherited disorders and sex determinationPolydactyly and cystic fibrosis, their dominant and recessive alleles, the case for and against embryo screening, the 23 chromosome pairs, XX and XY, and the chance of a boy.Open →
- VariationVariation caused by genes, the environment or both, why siblings and cloned plants differ, extensive genetic variation arising from mutations, how few variants affect the phenotype, and how a new phenotype suited to a changed environment can spread quickly.Open →
- EvolutionThe definition of evolution, natural selection and new species, why it acts on populations, simple life forms over three billion years ago, mutations as the source of variation, and the interbreeding test.Open →
- Selective breedingSelective breeding or artificial selection and its history, choosing and breeding parents over many generations, characteristics chosen in crops, farm animals, dogs and flowers, inbreeding and its problems, and the effects on variation and food production.Open →
- What genetic engineering is, and what it is used forThe definition of genetic engineering, where the new gene comes from, engineered crops and insulin from bacteria, cutting out and transferring a gene, and the benefits, objections and risks.Open →
- GM crops, their risks, and the steps of the processWhat genetically modified crops are and the insect and herbicide resistance and higher yields they give, concerns about wildlife and human health, hopes for overcoming inherited disorders, and the steps of genetic engineering using enzymes and plasmid or virus vectors at an early stage of development.Open →
- Evidence for evolution, and extinctionThe fossil record and antibiotic resistance as evidence, the discovery of genes, what extinction means, and how environmental change, disease, new predators, competition and low variation cause it.Open →
- FossilsWhat fossils are and where they form, preservation without decay, replacement by minerals and preserved traces, why early life left few, and reading evolutionary trees and common ancestors.Open →
- Resistant bacteriaWhy bacteria evolve rapidly, how mutation and antibiotic use produce and spread resistant strains such as MRSA, slowing resistance by limiting prescriptions, completing courses and restricting farm use, and the cost and slowness of developing new antibiotics.Open →
- Classification of living organismsThe Linnaean groups from kingdom to species, binomial names and what shared groups show about relatedness, how microscopes and biochemistry changed classification, Carl Woese's three domains of archaea, bacteria and eukaryota, and placing organisms on evolutionary trees.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
Why does sexual reproduction give varied offspring, where does a fertilised egg's genetic information come from, and how does asexual reproduction differ?
Process
How is the full number of chromosomes restored after gametes have been formed?
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Put these in order of size, largest first: gene, chromosome, nucleus.
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What is a gamete?
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Are most characteristics controlled by one gene or by many?
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Is polydactyly caused by a dominant or a recessive allele?
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What is meant by variation?
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What is evolution?
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What is selective breeding?
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Give two characteristics that crop plants have been genetically engineered to have.
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What is a genetically modified crop?
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Name two kinds of evidence for evolution.
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What are fossils?
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A population of bacteria doubles every 20 minutes. Explain why this makes resistance a serious problem.
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Which type of cell division produces cells that are genetically identical to one another?
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What is the first thing that happens in a cell that is about to divide to form gametes?
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What shape are the two strands of a DNA molecule twisted into?
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What is a chromosome?
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Why can a genetic cross only predict the likely proportions of the offspring?
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Which part of the cell is affected in cystic fibrosis?
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Give the three possible causes of variation between individuals.
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What can evolution eventually result in?
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Once the first generation of offspring has been produced, what is done next?
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What has to be put into a bacterial cell so that it will produce a human substance?
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Give two characteristics that genetically modified crops have been given.
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Give two factors that can contribute to the extinction of a species.
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How can a fossil form when no decay has taken place?
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Why does the population of a resistant strain rise?
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List the groups used by Linnaeus in order, from the largest to the smallest.
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Why are the cells produced by meiosis described as non-identical?
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How many sets of chromosomes does each gamete contain?
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What is a gene?
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What is an allele?
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In a family tree, a characteristic appears only in children whose parents do not show it. Is the allele responsible dominant or recessive?
Key term
Is cystic fibrosis caused by a dominant or a recessive allele?
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Give an example of a characteristic that is caused by genes alone.
Key term
Evolution acts on a population rather than on an individual. Explain why.
Key term
Why does selective breeding take many generations?
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Into what is a cut-out gene transferred?
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What effect does genetic modification usually have on the yield of a crop?
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How can competition cause a species to become extinct?
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Name a condition that must be missing if an organism's remains are not to decay.
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Give two reasons a resistant strain spreads quickly through a population of people.
Key term
Which two groups give an organism its binomial name?
Take Inheritance, Variation and Evolution further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Dominant allele vs Recessive allele
Dominant allele: a version of a gene that shows its effect with only one copy present. Recessive allele: a version of a gene that shows its effect only when two copies are present.
Genotype vs Phenotype
Genotype: the alleles an organism carries for a characteristic. Phenotype: the characteristics that an organism actually shows.
Homozygous vs Heterozygous
Homozygous: carrying two identical alleles for a characteristic. Heterozygous: carrying two different alleles for a characteristic.
Questions from this topic
Each one with the model answer underneath.
- 1
Which type of cell division produces cells that are genetically identical to one another?
Model answer
Mitosis produces genetically identical cells.
- 2
Why are the cells produced by meiosis described as non-identical?
Model answer
Meiosis produces cells that all differ from each other genetically, unlike mitosis, which produces identical copies.
- 3
What happens to the male and female gametes during sexual reproduction?
Model answer
They join together, or fuse, at fertilisation.
- 4
Name the male gamete and the female gamete in animals.
Model answer
The sperm cell is the male gamete and the egg cell is the female gamete.
- 5
Name the male gamete and the female gamete in flowering plants.
Model answer
Pollen is the male gamete and the egg cell is the female gamete.
- 6
Why does sexual reproduction produce offspring that vary?
Model answer
Genetic information from two parents is mixed, so the offspring are not identical to either parent or to each other.
What is inside Levo
Six ways to work the same material.
Inheritance, Variation and Evolution revision questions
- What does Inheritance, Variation and Evolution cover in AQA GCSE Combined Science Biology?
- 15 subtopics: sexual and asexual reproduction, meiosis, dna and the genome, genetic terms, dominant and recessive alleles, punnett squares, probability and genetic crosses, inherited disorders and sex determination, variation, evolution, selective breeding, what genetic engineering is, and what it is used for, gm crops, their risks, and the steps of the process, evidence for evolution, and extinction, fossils, resistant bacteria and classification of living organisms. Each one has its own page with questions and model answers.
- How is Inheritance, Variation and Evolution organised?
- By the AQA 8464 specification, subtopic by subtopic, so it matches the order you are taught it in.
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