Biology
G3N tutors you through the full Cambridge Biology syllabus offline — from The characteristics common to living organisms, Classification into kingdoms: animal, plant, fungus, bacterium and virus, The concept of species and the binomial naming system and more — with adaptive lessons, instant quizzes, flashcards and exam-ready summaries.
Syllabus
What you’ll cover in Biology.
The complete topic outline G3N teaches, mapped to the Cambridge curriculum.
IGCSECharacteristics and classification of living organisms
5 topicsThe characteristics common to living organisms
Classification into kingdoms: animal, plant, fungus, bacterium and virus
The concept of species and the binomial naming system
Constructing and using dichotomous keys
Features of the major invertebrate groups (Supplement)
IGCSEOrganisation of the organism
3 topicsCell structure: animal, plant, bacterial cells compared under the light microscope
Levels of organisation: cell, tissue, organ, organ system
Calculating magnification and actual size from a scale bar or drawing
IGCSEMovement into and out of cells
4 topicsDiffusion and the factors that affect its rate
Osmosis and its effect on plant and animal cells (turgor, plasmolysis)
Active transport as movement against a concentration gradient (Supplement)
Investigating diffusion and osmosis practically
IGCSEBiological molecules
4 topicsChemical elements present in carbohydrates, fats and proteins
Structure of large molecules as chains of smaller units
Food tests: reducing sugar, starch, protein and fat
Structure of DNA as two strands forming a double helix (Supplement)
IGCSEEnzymes
5 topicsEnzymes as biological catalysts and their properties
Enzyme action: lock-and-key model
Effect of temperature and pH on enzyme activity
Effect of substrate concentration on rate of reaction (Supplement)
Denaturation (Supplement)
IGCSEPlant nutrition
4 topicsPhotosynthesis: word and balanced chemical equation
Leaf structure related to function
Limiting factors: light intensity, carbon dioxide concentration, temperature
Mineral nutrition: magnesium and nitrate ions and their deficiency symptoms
IGCSEHuman nutrition
4 topicsA balanced diet and the roles of nutrients
The alimentary canal: ingestion, digestion, absorption, egestion
Physical and chemical digestion, including enzyme action on carbohydrates, proteins and fats
Absorption in the small intestine and the structure of a villus
IGCSETransport in plants
4 topicsStructure and function of xylem and phloem
Water uptake by root hair cells and movement through the plant
Transpiration and factors affecting transpiration rate
Translocation of sucrose and amino acids (Supplement)
IGCSETransport in animals
4 topicsThe circulatory system as a closed double circulation
Structure of the heart and blood vessels
Composition and functions of blood
Coronary heart disease and its risk factors (Supplement)
IGCSEDiseases and immunity
4 topicsPathogens and transmission of disease
Physical and chemical barriers to infection
The body's cellular defences: phagocytosis and antibody production
Antibiotics and antibiotic resistance (Supplement)
IGCSEGas exchange in humans
4 topicsStructure of the human gas exchange system
Gas exchange at the alveoli
Effects of physical activity on rate and depth of breathing
Effects of smoking on the gas exchange system
IGCSERespiration
3 topicsAerobic respiration: word and balanced chemical equation
Anaerobic respiration in living organisms and its uses (e.g. yeast)
Comparing energy release in aerobic and anaerobic respiration (Supplement)
IGCSEExcretion in humans
3 topicsExcretion as the removal of metabolic waste
Structure of the kidney and nephron (Supplement)
Ultrafiltration and selective reabsorption (Supplement)
IGCSECoordination and response
5 topicsThe nervous system: neurones, synapses and reflex actions
Sense organs: structure and function of the eye
Hormones and endocrine glands
Tropic responses in plants: phototropism and auxin (Supplement)
Homeostasis: control of body temperature and blood glucose (Supplement)
IGCSEDrugs
3 topicsMedicinal drugs, using antibiotics as an example
Effects of misused drugs: heroin and alcohol on the body
Effects of alcohol on reaction times and the liver (Supplement)
IGCSEReproduction
6 topicsAsexual and sexual reproduction compared
Structure of flowers and pollination
Fertilisation and seed/fruit formation in plants
The human reproductive systems and the menstrual cycle
Fertilisation, development of the embryo and the role of the placenta
Sexually transmitted infections, using HIV/AIDS as an example (Supplement)
IGCSEInheritance
4 topicsChromosomes, genes and alleles
Mitosis and meiosis and their significance
Monohybrid inheritance, including sex determination and codominance (Supplement)
Genetic diagrams and predicting the outcome of a genetic cross
IGCSEVariation and selection
4 topicsSources of variation: genetic and environmental
Continuous and discontinuous variation
Natural selection and its role in evolution (Supplement)
Selective breeding (Supplement)
IGCSEOrganisms and their environment
4 topicsEnergy flow through an ecosystem
Food chains, food webs and trophic levels
The carbon cycle and the water cycle
Population growth curves and limiting factors (Supplement)
IGCSEHuman influences on ecosystems
4 topicsFood supply: intensive farming and use of fertilisers and pesticides
Habitat destruction and deforestation
Pollution of water, air and land
Conservation of species and habitats (Supplement)
IGCSEBiotechnology and genetic modification
4 topicsUses of yeast in biotechnology: bread and biofuel production
Use of microorganisms to produce a named product (Supplement)
Genetic modification: principles and examples (Supplement)
Advantages and risks of genetically modified crops (Supplement)
A LevelCell structure (AS)
4 topicsCell structure as seen with a light microscope
Ultrastructure of animal and plant cells
Interpreting electron micrographs
Prokaryotic and eukaryotic cells compared
A LevelBiological molecules (AS)
4 topicsWater as a biological molecule
Structure and function of carbohydrates and lipids
Structure and function of proteins, including enzymes
Nucleic acids as information-carrying molecules
A LevelEnzymes (AS)
4 topicsMode of action of enzymes
Factors affecting enzyme action: temperature, pH, concentration
Enzyme inhibition: competitive and non-competitive
Immobilised enzymes and their industrial uses
A LevelCell membranes and transport (AS)
3 topicsFluid mosaic model of membrane structure
Movement across membranes: diffusion, osmosis, active transport
Effects of temperature and solvents on membrane structure
A LevelThe mitotic cell cycle (AS)
3 topicsChromosome behaviour during mitosis
Stages of the cell cycle
Uncontrolled cell division and tumour formation
A LevelNucleic acids and protein synthesis (AS)
4 topicsStructure of DNA and RNA
Semi-conservative DNA replication
Transcription and translation
The genetic code
A LevelTransport in plants (AS)
4 topicsStructure of xylem and phloem tissue
Water transport: root pressure, transpiration pull
Translocation of assimilates
Xerophytic adaptations
A LevelTransport in mammals (AS)
4 topicsStructure of the mammalian circulatory system
Structure and function of the heart
Transport of oxygen and carbon dioxide in the blood
Tissue fluid formation
A LevelGas exchange (AS)
3 topicsStructure of the gas exchange system in mammals
Gas exchange surfaces and their adaptations
Effects of lung disease on gas exchange
A LevelInfectious diseases (AS)
3 topicsInfectious disease and its transmission, using named examples
Antibiotics and mechanisms of antibiotic action
Antibiotic resistance in bacteria
A LevelImmunity (AS)
3 topicsNon-specific and specific immune responses
Antigens, antibodies and the immune response
Active and passive immunity, and vaccination
A LevelEnergy and respiration (A2)
4 topicsATP as the universal energy currency
Glycolysis, the Krebs cycle and oxidative phosphorylation
Anaerobic respiration in eukaryotes
Respiratory substrates
A LevelPhotosynthesis (A2)
4 topicsStructure of the chloroplast
Light-dependent and light-independent reactions
Factors limiting the rate of photosynthesis
Investigating photosynthesis experimentally
A LevelHomeostasis (A2)
4 topicsPrinciples of homeostasis and negative feedback
Control of blood glucose concentration
Structure and function of the kidney and nephron
Osmoregulation
A LevelControl and coordination (A2)
4 topicsStructure and function of neurones and synapses
The role of hormones, using auxin and insulin as examples
Nervous and hormonal communication compared
Homeostatic control of the internal environment
A LevelInheritance (A2)
4 topicsMeiosis and its significance in genetic variation
Monohybrid and dihybrid inheritance
Sex linkage and multiple alleles
Gene mutation and its causes
A LevelSelection and evolution (A2)
4 topicsVariation as the raw material for selection
Types of selection: stabilising, directional, disruptive
Evidence for evolution
Speciation
A LevelClassification, biodiversity and conservation (A2)
4 topicsClassification systems and phylogeny
Biodiversity within and between species
Threats to biodiversity
Conservation approaches, in situ and ex situ
A LevelGenetic technology (A2)
4 topicsPrinciples of genetic engineering
Recombinant DNA technology and gene cloning
Uses and ethical issues of genetic modification
Gene therapy
How G3N helps
Turn this syllabus into a pass.
Both tiers, one tutor
IGCSE and A Level content sit side by side, so the tutor follows you from Year 10 through to Year 13.
Structured by syllabus
Topics follow the organisation of the current Cambridge syllabus for each subject, not generic web answers.
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Generate questions per topic, get marked answers with explanations, and summarise dense readings before the paper.
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