The modules, one by one
Each area below lists the concepts named in the course document, what the TASC exam asks of them, and the mistake that most often costs marks.
- Experimental questions, variables and directional hypotheses
- Evidence quality, data representation and inquiry ethics
- Science as a human endeavour and internal inquiry folios
- Enzyme mechanisms and rate investigations
- Photosynthesis and cellular respiration
- DNA structure, replication and manipulation
- Protein synthesis and codon interpretation
- Gene expression, lac operon and mutation
- Neurons and synaptic transmission
- Negative feedback and blood glucose
- Thermoregulation
- Animal and plant water balance
- Pathogen types and transmission
- Innate immunity and inflammation
- Adaptive immunity
- Vaccination, immunity types and population protection
- Cell cycle, mitosis and meiosis
- Monohybrid inheritance and ABO blood groups
- X-linked inheritance and pedigree analysis
- Evolution and speciation
Area 1 of 20
Experimental questions, variables and directional hypotheses
Design begins with a biological question and an explicit relationship. Operational measurements, controlled conditions and appropriate replication support a justified conclusion. Explain why each decision improves the specific investigation, and keep the conclusion within the evidence collected.
What the course document lists under this area · 6 points
- Turn a biological observation into a testable question
- Identify the variable and its operational measurement
- Write a directional, mechanistically justified hypothesis
- Control competing explanations with specific decisions
- Choose replication and sampling that match the comparison
- Build a reproducible method and an honest conclusion
What the exam asks
External Criterion 3 (also internal): formulate testable biological questions and operational directional hypotheses, identify variables and design valid comparisons.
Where marks go missing
Writing a topic or question instead of a testable hypothesis.
Area 2 of 20
Evidence quality, data representation and inquiry ethics
Evidence evaluation links the measurement method to the biological claim. Preserve variation, choose informative graphs, distinguish association from causation and apply ethics to the actual investigation. State useful findings and their limits together.
What the course document lists under this area · 6 points
- Distinguish validity, reliability and measurement accuracy
- Summarise a dataset without concealing its variation
- Select graphs that preserve the biological relationship
- Reason from evidence to a bounded causal conclusion
- Apply ethical reasoning to the actual investigation
- Evaluate sources and communicate uncertainty transparently
What the exam asks
External Criterion 3 (also internal): analyse quantitative biological data, evaluate reliability/validity, identify limitations and justify improvements. Inquiry ethics and safety remain relevant to internal conduct; do not invent an external safety-folio task.
Where marks go missing
Using validity, reliability and accuracy as synonyms.
Area 3 of 20
Science as a human endeavour and internal inquiry folios
Human-endeavour analysis connects biology, evidence, technology, collaboration and consequences. The current internal folios require a traceable record of inquiry and sourced analysis. Keep internal work requirements distinct from the five externally assessed criteria.
What the course document lists under this area · 6 points
- Connect biological knowledge with how it was developed
- Analyse a discovery through a concrete case framework
- Plan the current practical skills and inquiry folios
- Develop the human-endeavour folio with traceable sources
- Use ethical attribution and distinguish evidence from advocacy
- Reconcile internal preparation with the external examination
What the exam asks
Internal-only Criteria 1,2,4 and the course work requirements: plan and communicate inquiry work and analyse science as a human endeavour/biological contexts. These internal tasks are not a separately submitted external folio or an external Criterion 4 section.
Where marks go missing
Treating a list of discoveries as analysis of science as a human endeavour.
Area 4 of 20
Enzyme mechanisms and rate investigations
Explain enzyme data by linking structure and productive interaction to rate. Distinguish slowing, inhibition, saturation and denaturation. In investigations, control quantities and conditions, measure an appropriate initial interval and interpret the actual axes.
What the course document lists under this area · 6 points
- Explain catalysis through structure and successful interaction
- Interpret temperature and pH effects without overgeneralising
- Distinguish substrate saturation from enzyme limitation
- Compare inhibition with support from cofactors and coenzymes
- Design an initial-rate enzyme experiment
- Construct complete explanations from unfamiliar enzyme data
What the exam asks
External Criterion 5 (also internal): explain enzyme structure–function relationships and analyse effects of substrate, inhibitors, pH and temperature on enzyme-mediated reactions.
Where marks go missing
Explaining low-temperature slowing as automatic denaturation.
Area 5 of 20
Photosynthesis and cellular respiration
Track balanced matter transformations, cellular locations and relative ATP production. Interpret gas exchange as a balance when photosynthesis and respiration occur together. Explain plateaus through limiting factors and choose measurements that represent the process under investigation.
What the course document lists under this area · 6 points
- Track matter and energy with balanced net equations
- Relate chloroplast structure to the stages of photosynthesis
- Follow glucose through aerobic respiration at course depth
- Compare aerobic and anaerobic pathways by outcomes
- Interpret limiting factors and net gas exchange
- Evaluate investigations of photosynthesis and respiration
What the exam asks
External Criterion 5 (also internal): analyse photosynthesis and cellular respiration, including matter/energy transformations, cellular locations and limiting-factor evidence.
Where marks go missing
Saying plants photosynthesise instead of respiring.
Area 6 of 20
DNA structure, replication and manipulation
Complementary bases allow DNA strands to act as copying templates. Explain the distinct required enzyme functions and semi-conservative products. Interpret fragment size and sequence evidence as different measurements, and keep genetic conclusions within their evidential limits.
What the course document lists under this area · 6 points
- Relate nucleotide structure to genetic information
- Use complementarity to explain accurate copying
- Assign the required replication enzymes distinct roles
- Explain the evidence logic of semi-conservative replication
- Distinguish DNA manipulation from copying an organism
- Interpret sequencing and fragment evidence cautiously
What the exam asks
External Criterion 5 (also internal): analyse DNA structure, complementary semi-conservative replication and course DNA manipulation/interpretation methods.
Where marks go missing
Confusing a nucleotide with its base component.
Area 7 of 20
Protein synthesis and codon interpretation
Identify the supplied molecule before deriving mRNA and interpreting codons. Keep transcription, RNA processing and translation distinct. Trace mutations through sequence changes, then qualify functional predictions according to the evidence.
What the course document lists under this area · 6 points
- Connect gene information to a functional protein
- Explain transcription as RNA construction from a template
- Distinguish RNA processing from changing DNA
- Explain translation through codons and matching transfer RNA
- Work a codon-chart question with explicit checking
- Evaluate the consequences of a changed sequence
What the exam asks
External Criterion 5 (also internal): explain transcription, RNA processing and translation and interpret sequences/codons to relate genetic information to polypeptides.
Where marks go missing
Looking up an anticodon in a chart intended for mRNA codons.
Area 8 of 20
Gene expression, lac operon and mutation
Use the lac operon to connect environmental conditions to protein production. Distinguish required Lac Z and Lac Y functions, regulation from sequence change, and mutation from selection. Build phenotype explanations from measurements at the relevant molecular stages.
What the course document lists under this area · 6 points
- Explain why cells regulate gene expression
- Model the lac operon with lactose absent and present
- Apply the current Lac Z and Lac Y requirement
- Classify mutations by the molecular change
- Separate expression changes from inherited sequence variation
- Evaluate a gene-to-phenotype argument using linked evidence
What the exam asks
External Criterion 5 (also internal): analyse gene expression and mutation, including current 2026 lacZ/β-galactosidase and lacY/permease requirements; lacA is not required.
Where marks go missing
Assuming every expression change requires a mutation.
Area 9 of 20
Neurons and synaptic transmission
Neural signalling depends on local membrane voltage changes, ion channels and maintained gradients. Signals regenerate along axons and pass chemically across synapses. Connect each stage to the relevant structure, then to its role in a defined homeostatic pathway.
What the course document lists under this area · 6 points
- Relate neuron structures to information transfer
- Explain resting potential through ions and permeability
- Describe threshold and the phases of an action potential
- Explain propagation without moving one spike as an object
- Trace chemical transmission across a synapse
- Connect neural signalling to homeostatic responses
What the exam asks
External Criterion 6 (also internal): explain neuronal signalling, action potentials and chemical synaptic transmission as mechanisms of homeostatic communication.
Where marks go missing
Treating the sodium-potassium pump as the channel causing each rapid spike phase.
Area 10 of 20
Negative feedback and blood glucose
Trace high and low blood glucose through their distinct hormonal responses and target actions. Complete the loop by explaining how correction reduces the initiating stimulus. Interpret time-series evidence cautiously and distinguish signal production from target responsiveness.
What the course document lists under this area · 6 points
- Build a complete negative-feedback explanation
- Trace the response to rising blood glucose
- Trace the response to falling blood glucose
- Compare endocrine targeting with neural communication
- Interpret glucose and hormone time-series data
- Evaluate a glucose-regulation model and its limitations
What the exam asks
External Criterion 6 (also internal): analyse negative-feedback components and blood-glucose regulation through pancreatic hormones and target responses.
Where marks go missing
Stopping the feedback explanation at hormone release.
Area 11 of 20
Thermoregulation
Explain thermoregulation through heat balance, detection and appropriate effectors. Distinguish blood-flow changes, evaporation, heat production and behaviour. Environmental conditions limit effectiveness, and the response must be linked back to the initial deviation.
What the course document lists under this area · 6 points
- Define the regulated condition and the heat balance
- Trace detection and control through negative feedback
- Explain vasodilation and vasoconstriction by blood distribution
- Distinguish sweating from successful evaporative cooling
- Compare shivering, insulation and behaviour in cold conditions
- Interpret thermoregulation evidence and model boundaries
What the exam asks
External Criterion 6 (also internal): analyse thermoregulatory responses and interactions among metabolic heat production, heat exchange and environmental conditions.
Where marks go missing
Treating skin temperature as identical to core temperature.
Area 12 of 20
Animal and plant water balance
Trace human water balance through detection, ADH, kidney reabsorption and urine changes. Explain plant water movement through xylem, cohesion and transpiration. Compare responses and adaptations by their effects on water loss and the tradeoffs they create.
What the course document lists under this area · 6 points
- Explain why water balance depends on solutes and movement
- Trace ADH feedback from detection to urine change
- Distinguish filtration from selective reabsorption in the nephron
- Explain the transpiration stream from roots to leaves
- Interpret environmental effects on transpiration
- Compare arid adaptations and integrate competing demands
What the exam asks
External Criterion 6 (also internal): analyse animal osmoregulation, ADH/kidney water reabsorption and plant water-balance responses including stomata/transpiration.
Where marks go missing
Treating ADH as a substance that physically carries water into blood.
Area 13 of 20
Pathogen types and transmission
Classify agents using their features and trace transmission through source, route and entry. Distinguish exposure from established infection and use denominators when comparing population evidence. Evaluate each control by the particular link it can interrupt.
What the course document lists under this area · 6 points
- Distinguish pathogen categories without treating all as cells
- Separate exposure, infection, disease and transmission
- Compare direct, fluid, food, water and airborne routes
- Explain vectors and pathogen adaptations functionally
- Interpret population disease data with denominators
- Evaluate control strategies by their place in the chain
What the exam asks
External Criterion 7 (also internal): distinguish pathogen types and explain transmission pathways and controls linked to those pathways.
Where marks go missing
Calling all pathogens cells or all microorganisms harmful.
Area 14 of 20
Innate immunity and inflammation
Innate protection combines barriers, inflammatory communication and phagocytic activity. Distinguish each cell role and measurement, then explain how antigen presentation connects the response to adaptive immunity. Larger visible responses are not automatically proof of better clearance.
What the course document lists under this area · 6 points
- Organise defence without turning it into a rigid timetable
- Compare structural, chemical and biological barriers
- Trace inflammation through mediators and vascular changes
- Explain phagocytosis as a membrane-mediated process
- Connect antigen presentation with adaptive activation
- Evaluate innate-response data without assuming more is always better
What the exam asks
External Criterion 7 (also internal): explain barriers, inflammation, phagocytosis and antigen presentation connecting innate and adaptive responses.
Where marks go missing
Treating the three defence lines as isolated stages that cannot overlap.
Area 15 of 20
Adaptive immunity
Adaptive responses depend on specific recognition, expansion and distinct effector roles. Plasma cells produce antibodies; T-cell populations coordinate, target and regulate responses. Memory supports later responses, while each measured immune outcome must be interpreted within its limits.
What the course document lists under this area · 6 points
- Explain specificity and clonal expansion
- Trace the B-cell response to plasma cells and antibodies
- Explain antibody action without making antibodies into cells
- Distinguish helper, cytotoxic, regulatory and memory T cells
- Interpret primary and secondary responses through memory
- Integrate humoral and cellular evidence in one explanation
What the exam asks
External Criterion 7 (also internal): analyse specific humoral and cell-mediated responses, clonal selection/expansion, effector functions and memory.
Where marks go missing
Saying an antigen manufactures antibodies.
Area 16 of 20
Vaccination, immunity types and population protection
Classify immunity by both mechanism and route. Vaccination stimulates active responses and memory, while passive transfer supplies existing antibodies. Population effects depend on transmission pathways and protection type, so compare defined endpoints and keep model assumptions explicit.
What the course document lists under this area · 6 points
- Classify immunity using source and mechanism separately
- Explain vaccination through antigen exposure and memory
- Compare passive protection with active memory formation
- Explain population protection through transmission opportunities
- Calculate comparative outcomes without overstating them
- Evaluate a transmission model and communicate its limits
What the exam asks
External Criterion 7 (also internal): distinguish active/passive and natural/artificial immunity, interpret primary/secondary responses and evaluate population-protection evidence.
Where marks go missing
Calling vaccination passive because material is administered from outside.
Area 17 of 20
Cell cycle, mitosis and meiosis
Track replication, chromosome sets and chromatid structure separately. Mitosis preserves sets; meiosis separates homologues then chromatids. Crossing over, assortment and fertilisation recombine variation, while mutation supplies new alleles.
What the course document lists under this area · 6 points
- Locate DNA replication within the cell cycle
- Trace mitosis through chromosome movement and cytokinesis
- Explain meiosis I through homologous chromosome separation
- Explain meiosis II and the relationship to fertilisation
- Connect independent assortment with genetic variation
- Interpret division diagrams and evaluate errors carefully
What the exam asks
External Criterion 8 (also internal): analyse the cell cycle, mitosis and meiosis, chromosome accounting and sources of inherited variation.
Where marks go missing
Saying DNA replication immediately doubles chromosome number under centromere counting.
Area 18 of 20
Monohybrid inheritance and ABO blood groups
Define the inheritance model, derive gametes and calculate genotype probabilities before assigning phenotypes. Dominance relationships and ABO notation change interpretation, not segregation logic. Expected ratios describe probabilities rather than guaranteed small-family outcomes.
What the course document lists under this area · 6 points
- Define alleles, genotype and phenotype before calculating
- Construct a Punnett square from gamete probabilities
- Use test-cross logic while respecting finite evidence
- Distinguish incomplete dominance from codominance
- Work ABO crosses using multiple alleles and codominance
- Check probabilities and distinguish expected from observed
What the exam asks
External Criterion 8 (also internal): solve monohybrid inheritance problems, including complete/incomplete dominance, codominance and ABO relationships.
Where marks go missing
Assuming dominant means common or beneficial.
Area 19 of 20
X-linked inheritance and pedigree analysis
Follow parental chromosome contributions and test every pedigree branch. Distinguish compatible from proven modes, retain unresolved genotypes and state assumptions. Conditional and whole-family probabilities require different denominators.
What the course document lists under this area · 6 points
- Set the sex-linked model and notation explicitly
- Calculate an X-linked recessive cross carefully
- Use X-linked dominant transmission as a discriminating pattern
- Eliminate autosomal models through informative relationships
- Represent genotype uncertainty instead of guessing
- Write a pedigree argument that addresses alternatives
What the exam asks
External Criterion 8 (also internal): infer possible genotypes and probabilities from X-linked and autosomal pedigree evidence while recognising ambiguity.
Where marks go missing
Putting an X-linked allele on Y in the ordinary model.
Area 20 of 20
Evolution and speciation
Mutation supplies variants; selection, drift and gene flow alter their representation. Explain reproductive contribution and the evidence distinguishing mechanisms. Isolation can permit divergence, while reduced diversity can increase vulnerability without determining every outcome.
What the course document lists under this area · 6 points
- Distinguish genetic variation from changes in its frequency
- Explain natural selection through differential reproduction
- Separate genetic drift, founder effects and bottlenecks
- Explain gene flow and interactions among mechanisms
- Trace geographical isolation towards speciation
- Evaluate diversity, extinction risk and evolutionary evidence
What the exam asks
External Criterion 8 (also internal): explain evolution through mutation, selection, drift and gene flow and analyse reproductive isolation/speciation evidence.
Where marks go missing
Calculating allele frequency by counting only dominant-phenotype individuals.