COMPLETE BIOLOGY ATLAS
Move from first principles to advanced evidence. Every unit, lesson, challenge, worked problem, practical skill and deep dive is indexed here.
SKILL COLLECTIONS
ALL FOUR LEVELS
Covers the shared characteristics of life, species and scientific naming, construction and use of dichotomous keys, the diagnostic features of major groups, and the use of evolutionary and DNA evidence in classification.
Covers plant, animal, and bacterial cell structures and functions; specialised cells; levels of organisation; biological drawing; and magnification with millimetre-micrometre conversion.
Covers diffusion, osmosis, active transport, concentration gradients, exchange surfaces, and investigations with plant tissue.
Covers the elemental composition and building blocks of carbohydrates, fats, proteins, and DNA; roles of water; and the standard food tests.
Covers enzymes as biological catalysts, active-site specificity, effects of temperature and pH, and rate investigations.
Covers photosynthesis, limiting factors, mineral nutrition, leaf structure, and standard investigations.
Covers balanced diet, alimentary-canal structure, physical and chemical digestion, digestive enzymes, absorption, assimilation, and egestion.
Covers xylem and phloem distribution and function, root water uptake, the transpiration stream, water-loss factors, and translocation between resources and sinks.
Covers the circulatory system, heart, blood vessels, blood components, lymph, and coronary heart disease.
Covers pathogens, transmissible disease, transmission control, body barriers, immune responses, vaccination, cholera, HIV, and public-health reasoning.
Covers airway anatomy, alveolar exchange, ventilation mechanics, exercise effects, inspired-expired air, and airway protection.
Covers cellular respiration, uses of released energy, aerobic and anaerobic word and symbol equations, lactate and oxygen debt, and rate investigations.
Covers metabolic waste, carbon dioxide and urea formation, urinary-system anatomy, kidney filtration and selective reabsorption, urine composition, and dialysis.
Covers nervous and hormonal coordination, reflexes and synapses, the eye, blood-glucose and temperature homeostasis, and plant tropisms with auxin.
For the 2026-2028 syllabus this focused topic defines drugs and covers antibiotics, bacterial resistance, and responsible antibiotic use.
Covers asexual and sexual reproduction, flowering-plant reproduction, human reproductive anatomy and development, sex hormones, menstrual control, and sexually transmitted infections.
Covers DNA, genes, alleles, proteins, sex determination, mitosis and meiosis, haploid and diploid nuclei, and genetic diagrams for monohybrid, test, codominant, and sex-linked crosses.
Covers continuous and discontinuous variation, mutation, adaptive features, natural selection, selective breeding, resistance, and hydrophyte/xerophyte adaptations.
Covers energy flow, food chains and webs, trophic levels, ecological pyramids, nutrient cycles, populations, communities, ecosystems, and sigmoid growth.
Covers food production, habitat loss, pollution, eutrophication, greenhouse gases and climate change, sustainable resource use, endangered species, and conservation.
Covers useful microorganisms, yeast and enzyme applications, fermenters, genetic modification, recombinant plasmids, and benefits and risks of modified organisms.
Covers light- and electron-microscope evidence, calibration and scale, eukaryotic and prokaryotic ultrastructure, specialised cells, and virus structure.
Covers water, monosaccharides, disaccharides, polysaccharides, lipids, amino acids, proteins, structure-function relationships, and biochemical tests.
Covers activation energy, active-site models, collision and kinetic reasoning, rate measurement, temperature, pH, enzyme and substrate concentration, competitive and non-competitive inhibition, and immobilised enzymes.
Covers phospholipid bilayers, membrane proteins, cholesterol and carbohydrates, cell signalling, diffusion, osmosis, facilitated diffusion, active transport, co-transport, endocytosis, and exocytosis.
Covers chromosome structure, DNA replication within interphase, mitosis, cytokinesis, cell-cycle significance, telomeres, stem cells, and cancer.
Covers nucleotide structure, DNA and RNA, semi-conservative replication, the genetic code, transcription, RNA processing at the required depth, translation, and gene mutation.
Covers vascular-tissue distribution, xylem structure, apoplast and symplast water movement, transpiration and stomatal control, cohesion-tension, phloem structure, and translocation by mass flow.
Covers closed double circulation, heart and vessel structure, the cardiac cycle, tissue fluid, blood components, haemoglobin and oxygen dissociation, carbon dioxide transport, and fetal haemoglobin where required.
Covers mammalian gas-exchange surface histology, ventilation, gradient maintenance, and interpretation of respiratory-disease evidence within the current syllabus boundary.
Covers pathogen classes, transmission, prevention, named disease mechanisms and control specified by the examination-year syllabus, antibiotics, and resistance.
Covers phagocytes, lymphocytes, antigens, clonal selection, antibody structure and action, primary and secondary responses, active and passive immunity, vaccination, autoimmune ideas where specified, and monoclonal antibodies.
Covers ATP, redox and coenzymes, glycolysis, link reaction, Krebs cycle, oxidative phosphorylation and chemiosmosis, anaerobic pathways, respiratory substrates, respiratory quotient, and respirometry.
Covers chloroplast structure, photosynthetic pigments, absorption and action spectra, light-dependent reactions, photophosphorylation, chemiosmosis, Calvin cycle, limiting factors, crop productivity, and adaptations of C4 plants where specified.
Covers homeostatic control systems, mammalian thermoregulation, kidney osmoregulation, ADH, blood-glucose control by insulin and glucagon, diabetes, and stomatal responses as plant homeostasis where specified.
Covers sensory neurones, resting and action potentials, saltatory conduction, synapses, neuromuscular junctions, skeletal-muscle contraction, endocrine coordination, and plant responses specified by the current syllabus.
Covers meiosis, genetic variation, monohybrid and dihybrid crosses, codominance, multiple alleles, sex linkage, autosomal linkage, crossing over, epistasis where specified, test crosses, pedigrees, chi-squared testing, mutation, and gene control in prokaryotes and eukaryotes.
Covers resources of variation, natural and artificial selection, antibiotic resistance, directional, stabilising and disruptive selection, evolution, genetic drift where specified, speciation, molecular evidence, and extinction.
Covers taxonomy and domains, phylogeny, molecular classification, species and ecosystem biodiversity, sampling design, Simpson's index, mark-release-recapture, correlation and selected statistics, threats, conservation methods, and international or local strategies.
Covers recombinant DNA, restriction enzymes and ligase, vectors and markers, PCR, gel electrophoresis, DNA profiling, sequencing, microarrays and bioinformatics where specified, medical and agricultural applications, gene therapy, and ethical evaluation.
This is the gold-standard expansion of Level 4 unit, Evolution, the Themes of Biology, and Scientific Inquiry. It turns the unit's organizing ideas into an original, resource-backed course of study. The course remains the primary reading; this deep dive supplies explanation, reasoning practice, evidence analysis, and modern research connections.
This is the deep expansion of Level 4 unit, The Chemical Context of Life. It connects introductory atomic and bonding models to quantitative chemistry, biological mechanisms, experimental evidence, and modern research.
This is the deep expansion of Level 4 unit, Water and Life. It connects molecular polarity to hydrogen-bond networks, organismal physiology, solution chemistry, environmental change, quantitative reasoning, and primary evidence.
This is the deep expansion of Level 4 unit, Carbon and the Molecular Diversity of Life. It follows carbon from prebiotic synthesis through molecular geometry, isomerism, functional groups, chemical reactivity, biological recognition, and ATP-coupled work.
This is the deep expansion of Level 4 unit, The Structure and Function of Large Biological Molecules. It connects covalent assembly to molecular sequence, three-dimensional structure, biological function, experimental evidence, genomic scale, and evolutionary comparison.
This is the deep expansion of Level 4 unit, A Tour of the Cell. It treats the cell as a measured, dynamic, compartmentalized system whose structures are inferred through microscopy, biochemical separation, molecular perturbation, and quantitative modeling.
This is the deep expansion of Level 4 unit, Membrane Structure and Function. It treats membranes as dynamic physical systems whose composition, topology, transport pathways, energy coupling, and vesicle traffic can be measured and tested.
This is the deep expansion of Level 4 unit, An Introduction to Metabolism. It treats metabolism as a measurable network governed simultaneously by conservation, thermodynamic direction, kinetic barriers, energy coupling, enzyme mechanism, spatial organization, and feedback control.
This is the deep expansion of Level 4 unit, Cellular Respiration and Fermentation. It follows carbon atoms, electrons, protons, ATP equivalents, compartments, and regulatory signals from fuel entry through glycolysis, pyruvate oxidation, the citric acid cycle, respiratory electron transport, ATP synthase, fermentation, and metabolic integration.
This is the deep expansion of Level 4 unit, Photosynthesis. It follows photons, excitation, electrons, protons, ATP, NADPH, carbon atoms, gases, compartments, and regulatory tradeoffs from light interception through the thylakoid reactions, Calvin cycle, photorespiration, C4 and CAM carbon concentration, biosynthesis, whole-plant integration, and planetary consequences.
This advanced study deep dive reconstructs Level 4 unit as a causal, quantitative, and experimental system. It covers the complete course unit span, pages 212-233, while keeping every claim tied to a compartment, measurement, perturbation, and interpretation boundary.
This advanced deep dive reconstructs Level 4 unit as a timed, mechanical, quantitative, and experimentally testable system. It covers course pages 234-252 and all three concepts while separating chromosome count from DNA content, phase accumulation from transition mechanism, and cultured-cell results from organismal or clinical claims.
This advanced deep dive reconstructs Level 4 unit as a chromosome-accounting, life-cycle, mechanical, quantitative, and evolutionary system. It covers course pages 254-268 and all four concepts while separating ploidy from DNA content, homologs from sisters, nuclear products from functional gametes, and the origin of variants from their meiotic reshuffling and later selection.
This advanced deep dive reconstructs Level 4 unit as an experimental, probabilistic, molecular, clinical, and ethical system. It covers course pages 269-293 and all four concepts while separating allele transmission from phenotype mapping, a probability from a realized family, dominance from fitness, and screening from diagnosis.
This advanced deep dive reconstructs Level 4 unit as a chromosome-state, crossing, mapping, cytogenetic, epigenetic, and extranuclear inheritance system. It covers course pages 294-313 and all five concepts while separating physical linkage from sex linkage, recombination fraction from physical distance, constitutional from somatic alterations, and imprinting from organelle inheritance.
This advanced deep dive reconstructs Level 4 unit as an information-storage, molecular-structure, replication, repair, chromosome-end, and chromatin-organization system. It covers course pages 314-334 and all three concepts while separating observation from inference, parental strands from parental molecules, DNA damage from fixed mutation, and chromatin packing models from direct measurements.
This advanced deep dive reconstructs Level 4 unit as an oriented information-conversion system. It covers course pages 335-364 and all five concepts while separating transcription from translation, template from coding strand, primary from mature RNA, codon from anticodon, tRNA charging from ribosomal energy use, sequence change from molecular consequence, and intended editing from verified function.
This advanced deep dive reconstructs Level 4 unit as a multiscale control system. It covers course pages 365-397 and all five concepts while separating DNA sequence from chromatin state, regulator binding from productive expression, transcription from RNA and protein turnover, determination from differentiation, and cancer predisposition from deterministic disease.
This advanced deep dive reconstructs Level 4 unit as a host-dependent information and transmission system. It covers course pages 398-414 and all three concepts while separating genome copies from particles and infectious units, attachment from entry, entry from productive infection, lytic growth from lysogeny and latency, mutation from reassortment, outbreak detection from viral origin, and protein requirement from a complete prion mechanism.
This advanced deep dive reconstructs Level 4 unit as a measurement-to-intervention pipeline. It covers course pages 415-441 and all four concepts while separating sequence signal from base call, physical DNA from cloned cells, amplification from quantification, expression from function, an edit from its repair outcome, nuclear-genome identity from phenotype, analytical validity from clinical utility, and technical feasibility from ethical authorization.
This advanced deep dive reconstructs Level 4 unit as a sequence-to-history inference pipeline. It covers course pages 442-466 and all six concepts while separating reads from assemblies, annotation from function, genome size from complexity, repetition from activity, duplication from innovation, similarity from homology, lineage specificity from adaptation, and a comparative association from a causal developmental mechanism.
This advanced deep dive reconstructs Level 4 unit as a pattern-to-process evidence system. It covers course pages 468-485 and all three concepts while separating evolution as an observed pattern from natural selection as a mechanism, development from population change, usefulness from adaptation, survival from reproductive success, homology from analogy, a tree from a ladder, historical inference from speculation, and scientific theory from an unsupported guess.
This advanced deep dive reconstructs Level 4 unit as a population-genetic accounting system. It connects the origin and reshuffling of variation to allele counting, Hardy-Weinberg expectations, selection, drift, founder events, bottlenecks, gene flow, relative fitness, sexual selection, balancing selection, and the constraints that prevent perfect adaptation.
This advanced deep dive reconstructs Level 4 unit as a gene-flow and reproductive-barrier evidence system. It covers species concepts, prezygotic and postzygotic isolation, allopatric and sympatric routes, polyploidy, ecological and sexual divergence, hybrid-zone dynamics, reinforcement, fusion, stability, speciation tempo, and the genetics of reproductive isolation.
This is an original study artifact: no course prose, figures, answer keys, or PDF content is reproduced. Page numbers are navigation markers. Questions, answers, calculations, diagrams in words, and explanations were independently written. The assessment bank contains original prompts, not course questions or an answer-key reconstruction.
This is an original study artifact: no course prose, figures, answer keys, or PDF content is reproduced. Page numbers are navigation markers. Questions, answers, calculations, diagrams in words, and explanations were independently written. The assessment bank contains original prompts, not course questions or an answer-key reconstruction.
This is an original study artifact: no course prose, figures, answer keys, or PDF content is reproduced. Page numbers are navigation markers. Questions, answers, calculations, diagrams in words, and explanations were independently written. The assessment bank contains original prompts, not course questions or an answer-key reconstruction.
This is an original study artifact: no course prose, figures, answer keys, or PDF content is reproduced. Page numbers are navigation markers. Questions, answers, calculations, diagrams in words, and explanations were independently written. The assessment bank contains original prompts, not course questions or an answer-key reconstruction.
This is an original study artifact: no course prose, figures, answer keys, or PDF content is reproduced. Page numbers are navigation markers. Questions, answers, calculations, diagrams in words, and explanations were independently written. The assessment bank contains original prompts, not course questions or an answer-key reconstruction.
This is an original study artifact: no course prose, figures, answer keys, or PDF content is reproduced. Page numbers are navigation markers. Questions, answers, calculations, diagrams in words, and explanations were independently written. The assessment bank contains original prompts, not course questions or an answer-key reconstruction.
This is an original study artifact: no course prose, figures, answer keys, or PDF content is reproduced. Page numbers are navigation markers. Questions, answers, calculations, diagrams in words, and explanations were independently written. The assessment bank contains original prompts, not course questions or an answer-key reconstruction.
This is an original study artifact: no course prose, figures, answer keys, or PDF content is reproduced. Page numbers are navigation markers. Questions, answers, calculations, diagrams in words, and explanations were independently written. The assessment bank contains original prompts, not course questions or an answer-key reconstruction.
This is an original study artifact: no course prose, figures, answer keys, or PDF content is reproduced. Page numbers are navigation markers. Questions, answers, calculations, diagrams in words, and explanations were independently written. The assessment bank contains original prompts, not course questions or an answer-key reconstruction.
This is an original study artifact: no course prose, figures, answer keys, or PDF content is reproduced. Page numbers are navigation markers. Questions, answers, calculations, diagrams in words, and explanations were independently written. The assessment bank contains original prompts, not course questions or an answer-key reconstruction.
This is an original study artifact with no course prose, figures, answer keys, or PDF content. Its assessment prompts are not course questions or an answer-key reconstruction. Page numbers are navigation markers; all explanations, prompts, diagrams in words, calculations, and solutions were independently written.
This is an original study artifact with no course prose, figures, answer keys, or PDF content. Its assessment prompts are not course questions or an answer-key reconstruction. Page numbers are navigation markers; all explanations, prompts, diagrams in words, calculations, and solutions were independently written.
This is an original study artifact with no course prose, figures, answer keys, or PDF content. Its assessment prompts are not course questions or an answer-key reconstruction. Page numbers are navigation markers; all explanations, prompts, diagrams in words, calculations, and solutions were independently written.## Purpose
This is an original study artifact with no course prose, figures, answer keys, or PDF content. Its assessment prompts are not course questions or an answer-key reconstruction. Page numbers are navigation markers; all explanations, prompts, diagrams in words, calculations, and solutions were independently written.## Purpose
An original, evidence-bounded learning system for plant sensing, signaling, development, stress physiology, and defense.
A advanced learning system for animal structure, homeostasis, thermoregulation, and bioenergetics.
A advanced learning system for animal nutrition, digestion, absorption, dietary adaptation, microbiomes, fuel regulation, and appetite.
A advanced learning system for circulation, blood, respiratory surfaces, ventilation, gas transport, quantitative physiology, and evidence reasoning.
A advanced learning system for innate recognition, adaptive specificity, immune effector routes, memory, disruption, quantitative reasoning, and evidence.
A advanced learning system for osmotic strategy, nitrogen disposal, excretory architectures, nephron transport, countercurrent gradients, endocrine control, quantitative reasoning, and evidence.
A advanced learning system for hormone signaling, receptor logic, feedback, neuroendocrine architecture, endocrine glands, rhythms, development, evolution, quantitative reasoning, and evidence.
A advanced learning system for reproductive modes, fertilization, anatomy, gametogenesis, endocrine cycles, pregnancy, birth, reproductive technology, quantitative reasoning, ethics, and evidence.
This original learning layer turns Level 4 unit into a advanced map of fertilization, cleavage, morphogenesis, cell fate, and evidence. It is written for Level 3 Biology through advanced study while keeping the first assessment tier genuinely accessible.
This original learning layer turns Level 4 unit into a advanced map of neuronal structure, membrane voltage, action potentials, axonal conduction, synapses, integration, transmitters, and evidence. It is written for Level 3 Biology through advanced study while keeping the first assessment tier genuinely accessible.
This original learning layer turns Level 4 unit into a advanced map of nervous-system organization, vertebrate brain specialization, cortical processing, plasticity, memory, and disorder evidence. It is written for Level 3 Biology through advanced study while keeping the first assessment tier genuinely accessible.
This original learning layer turns Level 4 unit into a advanced map of sensory reception, hearing, equilibrium, vision, taste, smell, muscle contraction, skeletal mechanics, and locomotion. It is written for Level 3 Biology through advanced study while keeping the first assessment tier genuinely accessible.
This original learning layer turns Level 4 unit into a advanced map of behavioral mechanism, development, learning, ecology, evolution, and social interaction. It is designed for Level 3 Biology through advanced study while keeping the first assessment tier genuinely accessible.
This original learning layer turns Level 4 unit into a advanced map of ecological scale, climate, terrestrial and aquatic biomes, distribution limits, and eco-evolutionary feedback. It supports Level 3 Biology through advanced study while keeping the first assessment tier genuinely accessible.
This is an original study artifact with no course prose, figures, answer keys, or PDF content. Its assessment prompts are not course questions or an answer-key reconstruction. Page numbers are navigation markers only. Explanations, models, datasets, questions, calculations, and answers were independently written. Unless a primary study is explicitly cited, numerical datasets are fictional teaching data.
This is an original study artifact with no course prose, figures, answer keys, or PDF content. Its assessment prompts are not course questions or an answer-key reconstruction. Page numbers are navigation markers only. Explanations, models, datasets, questions, calculations, and answers were independently written. Unless a primary study is explicitly cited, numerical datasets are fictional teaching data.
This is an original study artifact with no course prose, figures, answer keys, or PDF content. Its assessment prompts are not course questions or an answer-key reconstruction. Page numbers are navigation markers only. Explanations, models, datasets, questions, calculations, and answers were independently written. Unless a primary study is explicitly cited, numerical datasets are fictional teaching data.
This is an original study artifact with no course prose, figures, answer keys, or PDF content. Its assessment prompts are not course questions or an answer-key reconstruction. Page numbers are navigation markers only. Explanations, models, datasets, questions, calculations, and answers were independently written. Unless a primary study is explicitly cited, numerical datasets are fictional teaching data.
Fifty-six advanced biology units and every Level 1–3 topic are included in the atlas.