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
Homeostasis and Response
- 12 subtopics
- 36 things to know
- Paper 2
What Homeostasis and Response covers
Homeostasis and Response is examined in Biology Paper 2. It covers homeostasis and control systems; the nervous system and the reflex arc; the eye, accommodation and the correction of short and long sight; the brain and the control of body temperature; the endocrine system; insulin and diabetes; water and ion loss, the kidneys and kidney failure; hormones in reproduction and contraception; and plant hormones, phototropism and gravitropism.
Where it is assessed
Paper 2
Biology Paper 2: 1 hour 45 minutes, 100 marks, 50% of the GCSE.
Check the AQA specification ↗The 12 subtopics
Each one has its own page.
- HomeostasisWhat homeostasis is and why cells and enzymes need stable conditions, the control of blood glucose, body temperature and water level, nervous and hormonal responses, and the receptors, coordination centres and effectors of every control system.Open →
- The nervous system and the reflex arcHow the nervous system carries electrical impulses, the central nervous system and effectors, the stimulus to response pathway, sensory, relay and motor neurones and synapses in a reflex arc, why reflexes are rapid and automatic, and measuring reaction times, with anomalous results, reproducibility, range, uncertainty in a mean and significant figures.Open →
- The structure of the eye and accommodationThe retina, optic nerve, sclera, cornea and iris, how the iris muscles change pupil size in dim and bright light, accommodation for near objects as the ciliary muscles contract, the suspensory ligaments loosen and the lens thickens, and how the eye changes between near and distant focus.Open →
- Myopia, hyperopia and how they are correctedHow the eye focuses on distant objects as the ciliary muscles relax and the lens is pulled thin, short and long sightedness and where light is focused, and correction by spectacles with concave or convex lenses, contact lenses, laser surgery and lens replacement.Open →
- The brain and the control of body temperatureThe cerebral cortex, cerebellum and medulla, and how the thermoregulatory centre and skin receptors control body temperature through vasodilation and sweating when it is too high and vasoconstriction and shivering when it is too low.Open →
- Human endocrine systemWhat a hormone is and how it travels in the blood, hormonal against nervous effects, the pituitary as master gland, and the thyroid, adrenals, pancreas, ovaries and testes.Open →
- Insulin, glucagon and diabetesHow the pancreas releases insulin to move glucose into cells and store it as glycogen, why high blood glucose harms cells, the causes, signs and treatments of Type 1 and Type 2 diabetes, why insulin is injected, and reading glucose drink results.Open →
- Water and ion loss, and the production of ureaHow cells swell or shrink by osmosis when body fluids change concentration, uncontrolled water loss through the lungs and skin, why ions must be replaced after sweating, and the kidneys removing excess water, ions and urea in urine.Open →
- The kidneys, ADH and treating kidney failureHow the kidneys balance water and change urine volume, filtration and selective reabsorption of glucose, ions and water, interpreting protein, urea and glucose data, and dialysis and kidney transplants for kidney failure.Open →
- Hormones in human reproductionPuberty and secondary sex characteristics, oestrogen, testosterone and sperm production, ovulation about every 28 days, FSH and LH from the pituitary gland maturing and releasing an egg, and oestrogen and progesterone maintaining the uterus lining.Open →
- ContraceptionHormonal and non-hormonal contraception, including oral contraceptives, slow release progesterone by injection, implant or patch, barrier methods, intrauterine devices, spermicides, avoiding intercourse at fertile times and sterilisation, and the advantages and drawbacks of each.Open →
- Plant hormones and their usesPhototropism and gravitropism, how auxin makes shoots bend towards light and roots grow downwards, and investigating the effects of light and gravity on seedlings, with control variables and labelled drawings.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
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What is accommodation, and how does the lens change when the eye focuses on a near object?
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How does the thermoregulatory centre learn the temperature of the skin, and how does the body respond when too hot or too cold?
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What is meant by homeostasis?
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How is the structure of the nervous system suited to carrying information quickly?
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Explain why relaxing the ciliary muscles makes the lens thinner.
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What is a hormone?
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Describe what happens in the body between a sugary meal and blood glucose returning to normal.
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What happens to a body cell if the fluid around it becomes too dilute?
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What is the urine like after a person drinks a large volume of water?
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What do reproductive hormones cause to develop during puberty?
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What is contraception?
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What is phototropism?
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Changes that homeostasis responds to come from two sources. What are they?
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What two things does the nervous system allow humans to do?
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In a long sighted eye, where would rays from a near object be brought to a focus?
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What is the brain made of, and what does it control?
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What is the endocrine system made up of?
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What is the characteristic sign of untreated Type 1 diabetes?
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What happens to a body cell if the blood plasma around it becomes too concentrated?
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Explain why only a small volume of concentrated urine is produced on a hot day when little is drunk.
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Give two secondary sex characteristics that develop during puberty.
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Into which two groups are methods of contraception divided?
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What is gravitropism?
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Why does a stable internal environment matter to enzymes?
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In what form does information travel along a neurone?
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What is the eye, as a sense organ, sensitive to?
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What do short sightedness and long sightedness have in common?
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Why is the brain described as having different regions?
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Compare the speed and the duration of hormonal effects with nervous ones.
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Explain why insulin has to be injected rather than swallowed.
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Breathing onto a cold window leaves it misted. Which route of water loss does this show?
Process
Name the two processes by which the kidneys produce urine.
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What is the main female reproductive hormone, and where is it produced?
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How does avoiding intercourse at certain times of the cycle reduce the chance of pregnancy?
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Explain how a root turns downwards when a seed germinates on its side.
Take Homeostasis and Response further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Insulin vs Glucagon
Insulin: the pancreatic hormone that lowers blood glucose by making cells take it up. Glucagon: the pancreatic hormone that raises blood glucose by converting glycogen back to glucose.
Myopia vs Hyperopia
Myopia: short sightedness, where distant objects cannot be focused on the retina. Hyperopia: long sightedness, where near objects cannot be focused on the retina.
Vasoconstriction vs Vasodilation
Vasoconstriction: the narrowing of the blood vessels supplying the skin capillaries when the body is cold. Vasodilation: the widening of the blood vessels supplying the skin capillaries when the body is hot.
Questions from this topic
Each one with the model answer underneath.
- 1
What is meant by homeostasis?
Model answer
The regulation of the internal conditions of a cell or organism so that they stay at the optimum for its functions.
- 2
Changes that homeostasis responds to come from two sources. What are they?
Model answer
Changes inside the body itself and changes in the external environment.
- 3
Why must an organism hold its internal conditions within narrow limits?
Model answer
Its cells only work properly over a narrow range of conditions, so conditions have to be kept close to the optimum.
- 4
Why does a stable internal environment matter to enzymes?
Model answer
Enzymes only work at their fastest within a narrow range of temperature and pH, and homeostasis keeps conditions there.
- 5
Apart from enzyme action, what else does homeostasis keep at its optimum?
Model answer
All the other functions carried out by the cells of the body.
- 6
Name the three internal conditions controlled in the human body.
Model answer
Blood glucose concentration, body temperature and the water level of the body.
What is inside Levo
Six ways to work the same material.
Homeostasis and Response revision questions
- What does Homeostasis and Response cover in AQA GCSE Biology?
- 12 subtopics: homeostasis, the nervous system and the reflex arc, the structure of the eye and accommodation, myopia, hyperopia and how they are corrected, the brain and the control of body temperature, human endocrine system, insulin, glucagon and diabetes, water and ion loss, and the production of urea, the kidneys, adh and treating kidney failure, hormones in human reproduction, contraception and plant hormones and their uses. Each one has its own page with questions and model answers.
- How is Homeostasis and Response organised?
- By the AQA 8461 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Homeostasis and Response, 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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