AQA GCSE Biology Foundation: grade by grade

Every skill, from the first marks to the top grade. For each grade you also need the skills for the grades below it. Tick them off in the app's Notes section.

Grade 3

Grade 3 checklist (PDF)

Name eukaryotic and prokaryotic cells Animal and plant cells are eukaryotic; bacterial cells are prokaryotic. Eukaryotes and prokaryotes
Name the parts of an animal cell Nucleus, cytoplasm, cell membrane, mitochondria and ribosomes. Animal and plant cells
Name the extra structures in plant cells Chloroplasts, a permanent vacuole filled with cell sap, and a cell wall made of cellulose. Animal and plant cells
Name specialised animal and plant cells Sperm, nerve and muscle cells in animals; root hair, xylem and phloem cells in plants. Cell specialisation
State what cell differentiation is Differentiation is the process by which a cell becomes specialised for a particular function. Cell differentiation
State what magnification means How many times bigger the image is than the real object. Microscopy
State how bacteria reproduce Bacteria multiply by simple cell division called binary fission. Culturing microorganisms
State where chromosomes are found In the nucleus of a cell. Chromosomes
State what mitosis produces Two genetically identical cells. Mitosis and the cell cycle
State what a stem cell is An undifferentiated cell that can make more cells of the same type and can differentiate into other types of cell. Stem cells
Define diffusion The net movement of particles from an area of higher concentration to an area of lower concentration. Diffusion
Define osmosis The diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane. Osmosis
State what active transport is The movement of substances from a more dilute solution to a more concentrated solution, against a concentration gradient. Active transport
Put the levels of organisation in order From smallest to largest: cell → tissue → organ → organ system → organism. Principles of organisation
Name the organs of the digestive system Mouth and salivary glands, oesophagus, stomach, liver, gall bladder, pancreas, small intestine and large intestine. The human digestive system
Name the three types of blood vessel Arteries carry blood away from the heart, veins carry blood back to the heart, and capillaries link them inside tissues. The heart and blood vessels
Name the four components of blood Plasma, red blood cells, white blood cells and platelets. Blood
Name the vessels that supply heart muscle The coronary arteries supply the heart muscle with oxygenated blood. Coronary heart disease
Define health Health is the state of physical and mental well-being. Health issues
Define a risk factor A factor linked to an increased rate of a disease, such as part of a person's lifestyle or a substance in their body or environment. Lifestyle and non-communicable diseases
Define cancer Cancer is the result of changes in cells that lead to uncontrolled growth and division. Cancer
Name the tissues in a leaf Upper and lower epidermis, palisade mesophyll, spongy mesophyll, xylem and phloem, with guard cells around the stomata. Plant tissues
Name the parts of the plant transport system The roots, stem and leaves form an organ system; xylem carries water and phloem carries sugars. Plant organ system
Define a pathogen A pathogen is a microorganism that causes infectious (communicable) disease. Communicable (infectious) diseases
Name the four types of pathogen Viruses, bacteria, fungi and protists; they can infect both animals and plants. Communicable (infectious) diseases
Name viral diseases of humans and plants Measles and HIV in humans; tobacco mosaic virus (TMV) in plants. Viral diseases
Name two bacterial diseases Salmonella food poisoning and gonorrhoea, a sexually transmitted disease. Bacterial diseases
Name a fungal disease of plants Rose black spot is a fungal disease of roses. Fungal diseases
Name a disease caused by a protist Malaria is caused by a single-celled protist. Protist diseases
Name the body's non-specific defences The skin, the nose, the trachea and bronchi, and the stomach. Human defence systems
State what a vaccine contains Small quantities of a dead or inactive form of a pathogen. Vaccination
State what antibiotics do Antibiotics, such as penicillin, kill infective bacteria inside the body, curing bacterial diseases. Antibiotics and painkillers
State what painkillers do Painkillers treat the symptoms of a disease but do not kill pathogens. Antibiotics and painkillers
Match drugs to their original sources Digitalis from foxgloves, aspirin from willow, and penicillin from Penicillium mould (discovered by Alexander Fleming). Discovery and development of drugs
Name physical defences of plants Cellulose cell walls, a tough waxy cuticle on leaves, and layers of dead cells on stems (e.g. bark) that fall off. Plant defence responses
Write the word equation for photosynthesis carbon dioxide + water → glucose + oxygen, with light written above the arrow. Photosynthetic reaction
State where photosynthesis takes place In the chloroplasts of plant and algal cells, where chlorophyll absorbs light. Photosynthetic reaction
Name the factors affecting photosynthesis rate Temperature, light intensity, carbon dioxide concentration and the amount of chlorophyll. Rate of photosynthesis
List the five uses of glucose Respiration, starch for storage, fats or oils for storage, cellulose for cell walls, and amino acids for proteins. Uses of glucose from photosynthesis
State why organisms need energy For chemical reactions that build larger molecules, for movement and for keeping warm. Aerobic and anaerobic respiration
Write the word equation for aerobic respiration glucose + oxygen → carbon dioxide + water. Aerobic and anaerobic respiration
State how exercise changes heart and breathing Heart rate, breathing rate and breath volume all increase. Response to exercise
Define metabolism Metabolism is the sum of all the reactions in a cell or the body. Metabolism
Define homeostasis Regulating the internal conditions of a cell or organism to keep them at the optimum, in response to internal and external changes. Homeostasis
Name conditions controlled by homeostasis In humans: blood glucose concentration, body temperature and water levels. Homeostasis
State what the nervous system does It lets you react to your surroundings and coordinates your behaviour. Structure and function
Label the three main brain regions Identify the cerebral cortex, cerebellum and medulla on a diagram of the brain. The brain
Label the main parts of the eye Cornea, iris, pupil, lens, ciliary muscles, suspensory ligaments, retina, optic nerve and sclera. The eye
State normal core body temperature About 37 °C, the optimum for the body's enzymes. Control of body temperature
Define a hormone A chemical secreted by a gland directly into the bloodstream, which carries it to a target organ. Human endocrine system
Name the organ that controls blood glucose The pancreas monitors and controls blood glucose concentration. Control of blood glucose concentration
List ways water leaves the body From the lungs when you breathe out, from the skin in sweat, and from the kidneys in urine. Maintaining water and nitrogen balance
Name the main male and female hormones Testosterone from the testes; oestrogen from the ovaries. Hormones in human reproduction
Name hormonal and non-hormonal contraceptive methods E.g. the pill, implant, condom, diaphragm, IUD, spermicide, abstinence and sterilisation. Contraception
Define phototropism and gravitropism Phototropism is a growth response to light; gravitropism (geotropism) is a growth response to gravity. Control and coordination
Name the gametes in animals and plants Animals: sperm and egg cells. Flowering plants: pollen and egg cells. Sexual and asexual reproduction
State how many parents each type needs Sexual reproduction needs two parents; asexual reproduction needs only one. Sexual and asexual reproduction
State where and why meiosis happens Cells in the reproductive organs divide by meiosis to form gametes. Meiosis
State where DNA is found The genetic material in the nucleus is a chemical called DNA, contained in chromosomes. DNA and the genome
Define dominant and recessive alleles A dominant allele is expressed even with one copy; a recessive allele is expressed only with two copies. Genetic inheritance
Describe polydactyly and cystic fibrosis Polydactyly is having extra fingers or toes; cystic fibrosis is a disorder of cell membranes. Inherited disorders
State the number of chromosome pairs Ordinary human body cells contain 23 pairs of chromosomes. Sex determination
Define variation Differences in the characteristics of individuals in a population. Variation
Define evolution A change in the inherited characteristics of a population over time through natural selection. Evolution
Define selective breeding Humans breeding plants and animals for particular genetic characteristics. Selective breeding
Define a clone An organism that is genetically identical to another. Cloning
Name the scientist behind natural selection Charles Darwin developed the theory of evolution by natural selection. Theory of evolution
State what Wallace independently proposed Wallace independently proposed the theory of evolution by natural selection. Speciation
Name Mendel and the plants he used Gregor Mendel carried out breeding experiments on pea plants in the mid-19th century. The understanding of genetics
State that evolution is widely accepted The theory of evolution by natural selection is now widely accepted. Evidence for evolution
Define a fossil The remains of organisms from millions of years ago, which are found in rocks. Fossils
Define extinction A species is extinct when there are no remaining individuals of that species still alive. Extinction
Name an antibiotic-resistant bacterium MRSA is resistant to antibiotics. Resistant bacteria
List the Linnaean groups in order Kingdom, phylum, class, order, family, genus, species. Classification of living organisms
Define population, community, habitat and ecosystem A population is one species in a habitat, a community is all the populations there, and an ecosystem is the community interacting with the non-living environment. Communities
Define an abiotic factor A non-living factor in the environment that can affect a community. Abiotic factors
Define a biotic factor A living factor, such as another organism, that can affect a community. Biotic factors
Define an adaptation A feature that helps an organism survive in the conditions where it normally lives. Adaptations
Name producers and consumers in a food chain The producer comes first, then the primary, secondary and tertiary consumers. Levels of organisation
State that materials are recycled in ecosystems Materials cycle through the living and non-living parts of an ecosystem, providing the building blocks for new organisms. How materials are cycled
State what decomposers do Microorganisms such as bacteria and fungi break down dead organisms and waste. Decomposition
Define biodiversity The variety of all the different species of organisms on Earth, or within an ecosystem. Biodiversity
Name sources of water, air and land pollution Water: sewage, fertiliser, toxic chemicals. Air: smoke, acidic gases. Land: landfill, toxic chemicals. Waste management
Name ways humans use land Building, quarrying, farming and dumping waste. Land use
Define deforestation Cutting down large areas of forest so the land can be used for something else. Deforestation
Name two gases that contribute to global warming Carbon dioxide and methane. Global warming
Name programmes that protect biodiversity Breeding programmes, protecting rare habitats, hedgerows and field margins, reducing deforestation and carbon dioxide emissions, and recycling. Maintaining biodiversity
Number the trophic levels in a food chain Level 1 is the producer, level 2 the primary consumer, and so on along the chain. Trophic levels
Define biomass The mass of living material, often given per unit area, e.g. in g/m². Pyramids of biomass
Define food security Having enough food to feed a population. Factors affecting food security
State that fish stocks are declining Fish are being caught faster than they can reproduce (overfishing), so numbers in the oceans are falling. Sustainable fisheries
Name a food made from a fungus Mycoprotein, a protein-rich food made from the fungus Fusarium. Role of biotechnology

Grade 4

Grade 4 checklist (PDF)

Describe the structure of a bacterial cell Cytoplasm and a cell membrane inside a cell wall, a single loop of DNA not in a nucleus, and often plasmids. Eukaryotes and prokaryotes
State the function of each structure e.g. mitochondria are where aerobic respiration happens; ribosomes are where proteins are made. Animal and plant cells
State the function of each specialised cell e.g. a nerve cell carries electrical impulses; phloem carries dissolved sugars. Cell specialisation
Say when animal and plant cells differentiate Most animal cells differentiate at an early stage; many plant cells can differentiate throughout life. Cell differentiation
Calculate the total magnification of a microscope Multiply the eyepiece lens magnification by the objective lens magnification, e.g. ×10 and ×40 give ×400. Microscopy
Compare light and electron microscopes Electron microscopes have much higher magnification and resolution; light microscopes can show living cells in colour. Microscopy
Name two ways of growing bacteria In a nutrient broth solution, or as colonies on an agar gel plate. Culturing microorganisms
Describe what chromosomes are made of Chromosomes are made of DNA, and each chromosome carries a large number of genes. Chromosomes
State the chromosome number in human cells Body cells have 23 pairs (46 in total); sperm and egg cells have 23 single chromosomes. Chromosomes
Name the three stages of the cell cycle Growth and DNA replication; mitosis; division of the cytoplasm and cell membrane. Mitosis and the cell cycle
Name where stem cells are found In embryos, in adult bone marrow, and in the meristems of plants. Stem cells
Give examples of diffusion in living things Oxygen and carbon dioxide in gas exchange; urea from cells into the blood plasma. Diffusion
Predict the direction of water movement Water moves from the more dilute solution into the more concentrated solution. Osmosis
State where the energy comes from Active transport needs energy from respiration. Active transport
Define tissue, organ and organ system A tissue is a group of cells with a similar structure and function, an organ is a group of tissues working together, and an organ system is a group of organs working together. Principles of organisation
State what each digestive enzyme produces Amylase turns starch into sugars, proteases turn proteins into amino acids, and lipases turn lipids into fatty acids and glycerol. The human digestive system
Describe the food tests and positive results Benedict's turns from blue to brick red when heated with sugar, iodine from orange-brown to blue-black with starch, and Biuret from blue to purple with protein. The human digestive system
Label the heart's chambers and main vessels Right and left atria and ventricles, the vena cava, pulmonary artery, pulmonary vein, aorta and coronary arteries. The heart and blood vessels
State the function of each component Plasma transports dissolved substances, red blood cells carry oxygen, white blood cells defend against pathogens and platelets help the blood clot. Blood
Describe what happens in coronary heart disease Layers of fatty material build up inside the coronary arteries and narrow them. Coronary heart disease
Tell communicable and non-communicable diseases apart Communicable diseases are caused by pathogens and can spread; non-communicable diseases cannot be passed from one person to another. Health issues
Match risk factors to the diseases they affect Diet, smoking and lack of exercise → cardiovascular disease; obesity → type 2 diabetes; alcohol → liver and brain; smoking → lung disease and lung cancer; carcinogens → cancer. Lifestyle and non-communicable diseases
Describe a benign tumour A growth of abnormal cells contained in one area, usually within a membrane, that does not invade other parts of the body. Cancer
Label a leaf cross-section From top to bottom: waxy cuticle, upper epidermis, palisade mesophyll, spongy mesophyll with air spaces and veins, lower epidermis with stomata. Plant tissues
State where meristem tissue is found At the growing tips of shoots and roots, where cells divide to make new cells. Plant tissues
Define transpiration and translocation Transpiration is the loss of water vapour from the leaves; translocation is the movement of dissolved sugars through the phloem. Plant organ system
Describe how pathogens are spread By direct contact, by water and by air, and also in food, in body fluids and by vectors. Communicable (infectious) diseases
Describe the symptoms and spread of measles Fever and a red skin rash; it is spread by breathing in droplets from coughs and sneezes. Viral diseases
Describe how HIV is spread By sexual contact or by exchange of body fluids such as blood, e.g. when drug users share needles. Viral diseases
Give the symptoms of Salmonella food poisoning Fever, abdominal cramps, vomiting and diarrhoea, caused by the bacteria and the toxins they secrete. Bacterial diseases
Give the symptoms of gonorrhoea A thick yellow or green discharge from the vagina or penis, and pain on urinating. Bacterial diseases
Describe the symptoms of rose black spot Purple or black spots develop on the leaves, which often turn yellow and drop early. Fungal diseases
State how rose black spot is spread It is spread in the environment by water (e.g. splashing rain) or by wind. Fungal diseases
Describe the main symptom of malaria Recurrent episodes of fever (the fever keeps coming back); malaria can be fatal. Protist diseases
Identify the vector of malaria Mosquitoes carry the protist and pass it to people when they bite them. Protist diseases
Describe how each defence stops pathogens Skin is a barrier; mucus traps pathogens; cilia move the mucus away; stomach acid kills pathogens. Human defence systems
Name three ways white blood cells defend Phagocytosis, producing antibodies and producing antitoxins. Human defence systems
Describe what a vaccine makes the body do It stimulates white blood cells to produce antibodies against the pathogen. Vaccination
Explain why antibiotics don't treat viral diseases Antibiotics kill bacteria but cannot kill viruses. Antibiotics and painkillers
State what new drugs are tested for Toxicity (is it harmful?), efficacy (does it work?) and dose (how much should be given?). Discovery and development of drugs
Name chemical defences of plants Antibacterial chemicals, and poisons that deter herbivores. Plant defence responses
Name mechanical adaptations of plants Thorns and hairs, leaves that droop or curl when touched, and mimicry. Plant defence responses
Recognise the formulae of the four substances Carbon dioxide is CO₂, water is H₂O, glucose is C₆H₁₂O₆ and oxygen is O₂. Photosynthetic reaction
Explain what a limiting factor is The factor in shortest supply, which stops the rate of photosynthesis increasing; raising it raises the rate. Rate of photosynthesis
Describe the light intensity required practical Put pondweed at different distances from a lamp and count the oxygen bubbles, or measure the volume of oxygen, in a set time. Rate of photosynthesis
State what cellulose is used for Cellulose strengthens the cell wall of plant cells. Uses of glucose from photosynthesis
Name where plants store starch and oils Starch is stored in leaves, roots and tubers such as potatoes; many seeds store oils. Uses of glucose from photosynthesis
Write the anaerobic equations for muscles and yeast In muscles: glucose → lactic acid. In plant cells and yeast: glucose → ethanol + carbon dioxide. Aerobic and anaerobic respiration
Explain why heart and breathing rates increase To supply the muscles with more oxygenated blood for the extra respiration needed to contract. Response to exercise
Give examples of metabolic reactions For example respiration, making starch, glycogen or cellulose from glucose, making lipids and proteins, and making urea. Metabolism
Name the three parts of a control system Receptors, coordination centres and effectors. Homeostasis
Name the parts of the CNS The central nervous system (CNS) is the brain and spinal cord. Structure and function
Put the reflex arc in order Stimulus → receptor → sensory neurone → relay neurone → motor neurone → effector → response. Structure and function
State the function of each region Cerebral cortex: consciousness, intelligence, memory, language. Cerebellum: coordinates muscles. Medulla: unconscious activities. The brain
State the function of each part E.g. the retina contains light receptors; the optic nerve carries impulses to the brain. The eye
Name where temperature is monitored The thermoregulatory centre in the brain, which has receptors sensitive to blood temperature. Control of body temperature
List the responses to overheating Vasodilation and more sweat produced by sweat glands. Control of body temperature
Locate the main endocrine glands Pituitary, thyroid, adrenal glands, pancreas, ovaries and testes on a body diagram. Human endocrine system
Match glands to their hormones E.g. pancreas: insulin; testes: testosterone. Human endocrine system
Describe how insulin lowers blood glucose Insulin makes glucose move from the blood into cells; liver and muscle cells store it as glycogen. Control of blood glucose concentration
Describe how the kidneys produce urine Filtration of the blood, then selective reabsorption of useful substances such as glucose, some ions and water. Maintaining water and nitrogen balance
Define ovulation The release of a mature egg from an ovary, about every 28 days. Hormones in human reproduction
Explain how barrier methods work Condoms and diaphragms stop sperm reaching the egg. Contraception
Describe how shoots and roots respond Shoots grow towards light and against gravity; roots grow downwards, in the direction of gravity. Control and coordination
Define sexual reproduction The joining (fusion) of a male gamete and a female gamete. Sexual and asexual reproduction
State how many gametes meiosis produces The cell divides twice to form four gametes. Meiosis
Give an advantage of asexual reproduction Only one parent is needed, so there is no need to find a mate. Pros and cons of sexual and asexual reproduction
Give an advantage of sexual reproduction It produces variation in the offspring. Pros and cons of sexual and asexual reproduction
Describe the structure of DNA simply DNA is a polymer made up of two strands forming a double helix. DNA and the genome
Put nucleus, chromosome and gene in size order Nucleus (largest), then chromosome, then gene (a small section of DNA on a chromosome). DNA and the genome
Name the four bases in DNA The four bases are A, C, G and T. DNA structure
Use genotype, phenotype, homozygous and heterozygous correctly Genotype is the alleles present, phenotype is the characteristic; homozygous means the same alleles, heterozygous different. Genetic inheritance
State which allele causes each disorder Polydactyly is caused by a dominant allele; cystic fibrosis by a recessive allele. Inherited disorders
Give the sex chromosomes of each sex Females are XX; males are XY. Sex determination
Classify causes of variation Genetic (genes inherited), environmental (conditions of development) or a combination of both. Variation
State when simple life first developed All species evolved from simple life forms that first developed more than three billion years ago. Evolution
Give examples of chosen characteristics Disease resistance in crops, more meat or milk, gentle dogs, large or unusual flowers. Selective breeding
Define genetic engineering Modifying an organism's genome by introducing a gene from another organism to give a desired characteristic. Genetic engineering
Give examples of genetic engineering Bacteria that make human insulin; crops resistant to disease, insects or herbicides; bigger, better fruits. Genetic engineering
Describe taking cuttings Gardeners cut a piece from a parent plant and grow it into a new, identical plant. Cloning
Describe how Darwin developed his theory Observations on a round-the-world expedition, backed by experimentation and discussion with other scientists. Theory of evolution
Recall what Wallace is best known for His work on warning colouration in animals and his theory of speciation. Speciation
State Mendel's key observation The inheritance of each characteristic is determined by 'units' that are passed on to descendants unchanged. The understanding of genetics
Name two types of evidence for evolution The fossil record and the evolution of antibiotic resistance in bacteria. Evidence for evolution
Describe three ways fossils form Parts that have not decayed, parts replaced by minerals, and preserved traces such as footprints. Fossils
List the causes of extinction Environmental change, new predators, new diseases, new competitors and catastrophic events. Extinction
State ways to reduce antibiotic resistance Don't prescribe antibiotics for viral or non-serious infections, complete the course, and restrict their use in farming. Resistant bacteria
Use binomial names An organism's scientific name is its genus followed by its species, e.g. Homo sapiens. Classification of living organisms
List what plants compete for Light and space, and water and mineral ions from the soil. Communities
List what animals compete for Food, mates and territory. Communities
List the abiotic factors in the specification Light intensity, temperature, moisture level, soil pH and mineral content, wind intensity and direction, carbon dioxide (plants) and oxygen (aquatic animals). Abiotic factors
List the four biotic factors in the specification Availability of food, new predators arriving, new pathogens, and one species outcompeting another. Biotic factors
Classify adaptations as structural, behavioural or functional Structural means body features, behavioural means what it does, and functional means processes inside the body. Adaptations
State why food chains start with producers Producers (green plants and algae) make glucose by photosynthesis, so they produce the biomass for the rest of the chain. Levels of organisation
Calculate a mean, median and mode Mean = total ÷ number of values; median = middle value when in order; mode = most common value. Levels of organisation
Name the processes in the water cycle Evaporation, transpiration, condensation, precipitation, and water draining back into rivers and seas. How materials are cycled
Name the three factors affecting decay rate Temperature, water (moisture) and the availability of oxygen. Decomposition
Name human activities that reduce biodiversity For example pollution, building, farming, deforestation and destroying peat bogs. Biodiversity
Explain why more waste is produced The human population is growing rapidly and the standard of living is rising, so more resources are used. Waste management
Explain how land use reduces biodiversity Habitats are destroyed, so there is less space, food and shelter for other plants and animals. Land use
Give reasons for tropical deforestation To provide land for cattle and rice fields, and to grow crops for biofuels. Deforestation
Give human activities that increase these gases Burning fossil fuels, deforestation and destroying peat add carbon dioxide; cattle, rice fields and landfill add methane. Global warming
Describe producers, herbivores and carnivores Producers make their own food, herbivores eat plants or algae, and carnivores eat other animals. Trophic levels
Identify the trophic levels on a pyramid Trophic level 1 (the producers) is always the bottom bar. Pyramids of biomass
State the typical transfer percentages Producers transfer about 1% of the incident light energy for photosynthesis; about 10% of biomass passes to the next level. Transfer of biomass
List factors that threaten food security Rising birth rate, changing diets, new pests and pathogens, environmental change, the cost of agricultural inputs and conflicts. Factors affecting food security
Name ways to make animal farming more efficient Limit the animals' movement, control the temperature of their surroundings, and feed them high-protein food. Farming techniques
Name two methods to conserve fish stocks Controlling net (mesh) size and introducing fishing quotas. Sustainable fisheries
Describe how mycoprotein is produced Fusarium is grown on glucose syrup in aerobic conditions, then the biomass is harvested and purified. Role of biotechnology

Grade 5

Grade 5 checklist (PDF)

Compare prokaryotic and eukaryotic cells Say what both have (cell membrane, cytoplasm, ribosomes) and how they differ, above all whether the DNA is enclosed in a nucleus. Eukaryotes and prokaryotes
Convert between mm, µm and nm Multiply by 1000 for each step down (mm → µm → nm) and divide by 1000 for each step up. Eukaryotes and prokaryotes
Explain why some plant cells lack chloroplasts Cells that receive no light, such as root cells, cannot photosynthesise, so they have no chloroplasts. Animal and plant cells
Describe the adaptations of each specialised cell e.g. a sperm cell has a tail, many mitochondria and enzymes in its head. Cell specialisation
State what cell division does in adults In mature animals, cell division is mainly for repair and replacement. Cell differentiation
Use magnification = image size ÷ real size Rearrange the equation to find the magnification, the image size or the real size. Microscopy
Prepare a slide and focus a microscope Thin sample, stain, coverslip; start on the lowest power and focus with the coarse, then the fine, focus. Microscopy
Describe aseptic technique for preparing a culture Sterilise the dishes, media and inoculating loop, tape the lid, store the dish upside down and incubate at 25 °C. Culturing microorganisms
Put cell, nucleus, chromosome and gene in order Largest to smallest: cell, nucleus, chromosome, gene. Chromosomes
Describe what happens in each stage The cell grows, copies its sub-cellular structures and DNA, divides its nucleus, then splits in two. Mitosis and the cell cycle
State why mitosis is important For the growth and development of multicellular organisms, and to repair and replace cells. Mitosis and the cell cycle
Recognise where mitosis is happening e.g. a root tip growing, a cut healing, an embryo developing. Mitosis and the cell cycle
Compare embryonic and adult stem cells Embryonic stem cells can become most types of human cell; adult bone marrow stem cells form fewer types, including blood cells. Stem cells
Describe uses of meristem cloning Making clones quickly and cheaply, saving rare species, and producing crops with useful features. Stem cells
Explain the factors that affect the rate A bigger concentration gradient, a higher temperature and a larger surface area all increase the rate of diffusion. Diffusion
Describe the osmosis required practical Weigh pieces of plant tissue, leave them in a range of concentrations, then reweigh them. Osmosis
Calculate percentage change in mass Change in mass ÷ starting mass × 100; a loss in mass gives a negative answer. Osmosis
Describe two examples of active transport Mineral ions from the soil into root hair cells; sugar from the gut into the blood. Active transport
Classify a structure by its level For example, a red blood cell is a cell, blood is a tissue, the heart is an organ and the circulatory system is an organ system. Principles of organisation
Recall where each digestive enzyme is made Amylase in the salivary glands, pancreas and small intestine; proteases in the stomach, pancreas and small intestine; lipases in the pancreas and small intestine. The human digestive system
Describe the double circulatory system The right ventricle pumps blood to the lungs and the left ventricle pumps blood around the rest of the body. The heart and blood vessels
Describe the role of the pacemaker A group of cells in the right atrium controls the natural resting heart rate; an artificial pacemaker is an electrical device that corrects an irregular heart rate. The heart and blood vessels
Identify blood cells in a photo or diagram Red blood cells are biconcave discs with no nucleus, white blood cells are larger with a nucleus, and platelets are tiny fragments. Blood
List substances transported by the plasma Carbon dioxide, urea, soluble products of digestion such as glucose and amino acids, hormones and antibodies. Blood
Describe how stents and statins treat CHD A stent holds the coronary artery open; statins lower blood cholesterol, which slows the build-up of fatty material. Coronary heart disease
Describe treatments for faulty valves and heart failure Faulty valves are replaced with biological or mechanical valves; heart failure can be treated with a donor heart (or heart and lungs) or, occasionally, an artificial heart. Coronary heart disease
Give factors other than disease affecting health Diet, stress and life situations can have a big effect on both physical and mental health. Health issues
Describe effects of smoking and alcohol in pregnancy Both can harm the unborn baby, e.g. smoking can cause low birth weight and alcohol can damage the baby's brain development. Lifestyle and non-communicable diseases
Describe malignant tumours and secondary tumours Malignant tumour cells are cancers: they invade neighbouring tissues and spread in the blood to form secondary tumours. Cancer
Give lifestyle risk factors for cancer For example smoking (lung cancer), obesity (e.g. bowel cancer), too much UV light (skin cancer) and some viral infections (e.g. cervical cancer). Cancer
State the function of each leaf tissue Epidermis covers the leaf, palisade does most photosynthesis, spongy mesophyll lets gases diffuse, xylem carries water and phloem carries sugars. Plant tissues
Describe how root hair cells absorb substances They take up water by osmosis and mineral ions by active transport, helped by their large surface area. Plant organ system
Compare the structure of xylem and phloem Xylem is hollow tubes strengthened by lignin; phloem is tubes of elongated cells with pores in the end walls. Plant organ system
Explain how bacteria and viruses make you ill Both reproduce rapidly in the body; bacteria release toxins that damage tissues, and viruses reproduce inside cells and damage them. Communicable (infectious) diseases
Describe ways to reduce the spread of disease Hygiene, isolating infected individuals, destroying or controlling vectors, and vaccination. Communicable (infectious) diseases
Describe how measles and HIV are controlled Measles: vaccinating young children; HIV: condoms, not sharing needles and antiretroviral drugs. Viral diseases
Describe how each disease is spread Salmonella: bacteria swallowed in food or on food prepared in unhygienic conditions; gonorrhoea: sexual contact. Bacterial diseases
Describe how the spread of each is controlled Vaccinating poultry and hygienic food preparation for Salmonella; antibiotics and condoms for gonorrhoea. Bacterial diseases
Describe how rose black spot is treated Use fungicides and/or remove and destroy the affected leaves. Fungal diseases
Describe how the spread of malaria is controlled Stop mosquitoes breeding, and use mosquito nets to avoid being bitten. Protist diseases
Describe phagocytosis A white blood cell engulfs a pathogen and digests it. Human defence systems
Explain how vaccination prevents illness If the live pathogen enters later, white blood cells quickly make the correct antibodies and destroy it before it causes illness. Vaccination
Explain why specific antibiotics are needed Different antibiotics kill different bacteria, so the antibiotic must match the bacterium causing the disease. Antibiotics and painkillers
Describe preclinical testing The drug is tested in a laboratory on cells, tissues and live animals before any people take it. Discovery and development of drugs
Describe the stages of clinical trials Very low doses are given first to check safety; further trials on patients find the optimum dose. Discovery and development of drugs
Give examples of plant pathogens and pests Tobacco mosaic virus (a virus), rose black spot (a fungus) and aphids (insects). Detection and identification of plant diseases
Explain how physical barriers stop pathogens They are barriers that pathogens cannot easily get through, and dead cells take pathogens with them when they fall off. Plant defence responses
Explain why photosynthesis is endothermic Energy is transferred from the environment to the chloroplasts by light, so the reaction takes in energy. Photosynthetic reaction
State where the reactants come from Carbon dioxide diffuses into the leaf from the air through the stomata; water is absorbed by the roots and carried up in the xylem. Photosynthetic reaction
Explain the effect of temperature The rate rises up to an optimum temperature, then falls quickly because the enzymes that control photosynthesis denature. Rate of photosynthesis
Explain a one-factor rate graph Where the line rises the factor on the x-axis is limiting; where it levels off another factor has become limiting. Rate of photosynthesis
Describe how glucose reaches storage organs Sugars made in the leaves are carried in solution in the phloem to where they are used or stored. Uses of glucose from photosynthesis
Describe respiration as a continuous exothermic reaction It happens all the time in living cells and transfers energy to the surroundings, supplying the energy for living processes. Aerobic and anaerobic respiration
Describe fermentation and its uses Anaerobic respiration in yeast makes ethanol and carbon dioxide, which are used to make alcoholic drinks and bread. Aerobic and anaerobic respiration
Explain when muscles respire anaerobically When oxygen cannot be supplied fast enough for aerobic respiration alone, as in vigorous exercise. Response to exercise
Calculate changes from exercise data Work out increases, percentage changes and recovery times from tables and graphs of heart rate or breathing rate. Response to exercise
Name the building blocks of large molecules Carbohydrates are made from sugars, proteins from amino acids, and lipids from glycerol and fatty acids. Metabolism
State how a lipid molecule forms One molecule of glycerol joins with three molecules of fatty acids. Metabolism
Explain why homeostasis is important It keeps conditions at the optimum for enzyme action and all cell functions. Homeostasis
Describe the job of each part Receptors detect stimuli, coordination centres process the information, and effectors (muscles or glands) bring about a response. Homeostasis
Explain why reflex actions are fast They are automatic and do not involve the conscious part of the brain. Structure and function
Describe the ruler-drop reaction time practical Catch a dropped ruler, record the distance it fell and convert it to a reaction time. Structure and function
Describe how the pupil changes with light The pupil widens in dim light to let more light in and narrows in bright light. The eye
List the responses to being too cold Vasoconstriction, sweating stops, and skeletal muscles contract (shivering). Control of body temperature
Compare hormonal and nervous control Hormones travel in the blood and are slower but longer-lasting; nerve impulses are fast and short-lived. Human endocrine system
Compare the causes of Type 1 and 2 Type 1: the pancreas does not make enough insulin. Type 2: body cells stop responding to insulin. Control of blood glucose concentration
Describe treatments for each type of diabetes Type 1: insulin injections. Type 2: a carbohydrate-controlled diet and an exercise regime. Control of blood glucose concentration
Explain why cell water content must be controlled If cells gain or lose too much water by osmosis, they do not function efficiently. Maintaining water and nitrogen balance
Describe the basic principles of dialysis Blood flows past a partially permeable membrane; urea and excess ions diffuse into the dialysis fluid. Maintaining water and nitrogen balance
State the roles of the four cycle hormones FSH matures an egg, LH triggers its release, and oestrogen and progesterone maintain the uterus lining. Hormones in human reproduction
Explain how hormonal methods work The pill inhibits FSH so no eggs mature; progesterone implants stop eggs maturing and being released. Contraception
Describe how IUDs and spermicides work IUDs prevent an embryo implanting or release a hormone; spermicides kill or disable sperm. Contraception
Describe the seedling growth practical Grow seedlings with light from one side, or on their side, and record both lengths and direction of growth. Control and coordination
Name the cell division each type uses Gametes are made by meiosis; asexual reproduction involves only mitosis. Sexual and asexual reproduction
Describe what happens in meiosis The genetic information is copied, then the cell divides twice to give four genetically different gametes, each with a single set of chromosomes. Meiosis
Give chromosome numbers in body cells and gametes A human body cell has 46 chromosomes (23 pairs) and a human gamete has 23. Meiosis
Explain why variation helps a species survive If the environment changes, some individuals are likely to have characteristics that help them survive, by natural selection. Pros and cons of sexual and asexual reproduction
Define gene and genome A gene is a small section of DNA on a chromosome; the genome is all of an organism's genetic material. DNA and the genome
Describe the structure of a nucleotide A common sugar and a phosphate group, with one of four bases attached to the sugar. DNA structure
Describe DNA as a polymer of nucleotides Long strands of alternating sugar and phosphate sections, with a base attached to each sugar. DNA structure
Complete a Punnett square Put each parent's gametes on the outside and combine one allele from each in every box. Genetic inheritance
Give cross outcomes as ratios or probabilities For example 3 : 1, or a probability of 0.25, 25%, ¼ or 1 in 4. Genetic inheritance
Explain what a carrier is A heterozygous person with one recessive allele who does not have the disorder but can pass it on. Inherited disorders
State what the other 22 pairs do 22 pairs control characteristics only; one pair carries the genes that determine sex. Sex determination
Draw a genetic cross for sex XX × XY in a Punnett square gives XX, XX, XY, XY. Sex determination
Give examples of each cause Blood group is genetic, a scar is environmental, and body mass depends on both. Variation
State that populations show genetic variation There is usually extensive genetic variation within a population of a species. Variation
List the steps of natural selection Variation, competition, the best suited survive and reproduce, alleles passed on, alleles become more common. Evolution
Describe the steps of selective breeding Choose parents with the characteristic, breed them, select the best offspring, and repeat over many generations. Selective breeding
State what GM crops are Crops whose genes have been modified by genetic engineering; they generally give increased yields. Genetic engineering
Describe tissue culture and its uses Small groups of cells from part of a plant are grown into identical plants, to preserve rare species or for nurseries. Cloning
Describe Darwin's theory Variation exists; the individuals most suited to the environment are more likely to survive to breed and pass on their characteristics. Theory of evolution
Describe how Wallace influenced Darwin Their joint writings in 1858 prompted Darwin to publish On the Origin of Species in 1859. Speciation
Define a species A group of organisms that can interbreed to produce fertile offspring. Speciation
Put the development of gene theory in order Mendel's units, chromosomes seen in cell division, units linked to chromosomes, then the structure of DNA. The understanding of genetics
Explain why genes support Darwin's theory It has been shown that characteristics are passed on to offspring in genes, which explains how they are inherited. Evidence for evolution
Explain why some remains do not decay One or more of the conditions needed for decay (such as oxygen, warmth or moisture) are absent. Fossils
Give examples of catastrophic events Massive volcanic eruptions or collisions with asteroids. Extinction
Explain why bacteria evolve rapidly They reproduce at a fast rate, so there are many generations in a short time. Resistant bacteria
Describe how Linnaeus classified organisms Into groups depending on their structure and characteristics. Classification of living organisms
Name the three domains Archaea, bacteria and eukaryota. Classification of living organisms
Explain what interdependence means Each species depends on others for food, shelter, pollination or seed dispersal, so removing one species can affect the whole community. Communities
Describe a trend in abiotic data State how one variable changes as the other changes, quoting values from the table or graph. Abiotic factors
Explain the effect of food availability More food means more organisms survive and breed, so the population grows; less food has the opposite effect. Biotic factors
Define an extremophile and give an example An organism that lives in extreme conditions of temperature, pressure or salt concentration, e.g. bacteria in deep sea vents. Adaptations
Describe using quadrats to estimate population size Place quadrats randomly, count the organisms, find the mean per quadrat, then scale up to the whole area. Levels of organisation
Name processes that add or remove carbon dioxide Photosynthesis removes carbon dioxide from the air; respiration and combustion release it. How materials are cycled
Describe how compost and biogas are produced Waste decays in warm, moist, well-aerated heaps to make compost; anaerobic decay in a biogas generator makes methane. Decomposition
Explain why biodiversity matters to humans The future of humans relies on it, e.g. for food, materials, medicines and stable ecosystems. Biodiversity
Explain how pollution reduces biodiversity Pollution kills plants and animals, so fewer species survive in the area. Waste management
State why peat bogs are destroyed Peat is dug up to produce garden compost. Land use
Explain how deforestation reduces biodiversity Forest habitats are destroyed and replaced by grazing land or one crop, so many species are lost. Deforestation
Describe biological consequences of global warming Habitat loss as sea levels rise, changes in distribution and migration, and loss of biodiversity. Global warming
Explain how each programme helps biodiversity Say what the programme does and which species or habitats it protects. Maintaining biodiversity
Define an apex predator A carnivore with no predators. Trophic levels
Describe the shape of a pyramid of biomass Each bar is smaller than the one below, because biomass decreases at each trophic level. Pyramids of biomass
Describe how biomass is lost between levels Parts not eaten, egestion in faeces, carbon dioxide and water from respiration, and urea and water in urine. Transfer of biomass
Explain how pests and pathogens threaten food supplies They destroy crops or kill farm animals, so less food is produced. Factors affecting food security
Explain why high-protein food increases growth Protein is digested into amino acids, which animals use to make the proteins needed for growth. Farming techniques
Explain why fish stocks must be maintained If too few fish are left to breed, the species may disappear altogether in some areas. Sustainable fisheries
Describe how GM bacteria produce insulin Bacteria given the human insulin gene are grown in large numbers, and the insulin is harvested and purified. Role of biotechnology

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