Key term
AQA GCSE Biology 8461
Bioenergetics
Cell Biology
Topic overviewEukaryotes and prokaryotesAnimal and plant cellsCell specialisation and differentiationMicroscopyGrowing bacteria and aseptic techniqueCalculating bacterial growth, and testing antiseptics and antibioticsChromosomes, 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 cycledDecompositionWaste management and biodiversityLand use, deforestation and global warmingMaintaining biodiversityTrophic levels and pyramids of biomassTransfer of biomassFactors affecting food securityFarming techniques and sustainable fisheriesRole of biotechnology
Homeostasis and Response
Topic overviewHomeostasisThe nervous system and the reflex arcThe structure of the eye and accommodationMyopia, hyperopia and how they are correctedThe brain and the control of body temperatureHuman endocrine systemInsulin, glucagon and diabetesWater and ion loss, and the production of ureaThe kidneys, ADH and treating kidney failureHormones in human reproductionContraceptionPlant hormones and their uses
Infection and Response
Inheritance, Variation and Evolution
Topic overviewSexual and asexual reproductionMeiosisAdvantages and disadvantages of sexual and asexual reproductionDNA and the genomeDNA as a polymer of four nucleotidesGenetic 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 processCloningDarwin, Lamarck and the acceptance of evolutionSpeciationThe understanding of geneticsEvidence 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
Cell Biology
Growing bacteria and aseptic technique
- 3 things to know
- Paper 1
Overview
Binary fission and how fast bacteria divide, growing bacteria in nutrient broth or as colonies on agar plates, why cultures must be uncontaminated, and aseptic technique, from sterilising dishes and flaming the inoculating loop to taping lids, storing plates upside down and incubating at 25 °C.
What you need to know
Answer each one before you reveal it.
Your recallNot started
Process
By what process do bacteria reproduce?
Key term
How often can bacteria divide in ideal conditions?
Questions from this subtopic
Each one with the model answer underneath.
- 1
By what process do bacteria reproduce?
Model answer
Simple cell division, called binary fission.
- 2
How often can bacteria divide in ideal conditions?
Model answer
As often as once every 20 minutes.
- 3
What two conditions do bacteria need in order to divide as rapidly as possible?
Model answer
Enough nutrients and a suitable temperature.
- 4
Suggest why bacteria in a sealed culture eventually stop dividing so quickly.
Model answer
The nutrients in the culture are used up, so growth slows.
- 5
Name two ways bacteria can be grown in a laboratory.
Model answer
In a nutrient broth solution, or as colonies on an agar gel plate.
- 6
What is a bacterial colony?
Model answer
A visible patch of many bacteria on an agar plate, all grown by division from one original cell.
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