Subjects / Leaving Certificate / Biology
Mapped to: Leaving Certificate Biology – established syllabus (Units 1–3; last examined June 2026) plus the revised NCCA specification for students who started 5th year in September 2025 (first examined 2027: Unifying strand Nature of Science; Strand 1 Organisation of Life; Strand 2 Structures and Processes of Life; Strand 3 Interactions of Life). Topics marked '(2025 spec)' are new to the revised specification. · official specification (NCCA). Topic names are StudyRoom's own summaries.
Unit 1: The Study of Life
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The scientific method and experimentationHypotheses, controls, replicates, sample size and the limitations of science.HLOL 16 q
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Characteristics of lifeOrganisation, nutrition, excretion, response and reproduction; metabolism and continuity of life.HLOL 15 q
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Food: biomolecules and food testsCarbohydrates, lipids, proteins, vitamins and minerals, their elements, roles and tests.HLOL 18 q
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General principles of ecologyBiosphere, ecosystem, habitat, niche, food chains, food webs and pyramids of numbers.HLOL 18 q
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Nutrient recycling: carbon and nitrogen cyclesHow carbon and nitrogen are recycled by living things.HLOL 16 q
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Population dynamics and interactionsCompetition, predation, symbiosis and factors controlling population size.HLOL 16 q
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Human impact on ecosystemsPollution, conservation and waste management.HLOL 16 q
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Study of an ecosystem (fieldwork)Identifying, collecting and estimating organisms and measuring abiotic factors.HLOL 21 q
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Biodiversity, Simpson's Diversity Index and carrying capacity (2025 spec)Biodiversity loss and conservation, Simpson's Diversity Index, limiting factors, J- and S-shaped population curves and pyramids of biomass. Added for the revised specification (students starting 5th year from September 2025).HLOL 19 q
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Microbiomes, nutrient cycling and climate change (2025 spec)The human gut and soil microbiomes, factors affecting microbial growth, CO2 and methane in climate change and biological strategies to reduce them. Added for the revised specification (students starting 5th year from September 2025).HLOL 15 q
Unit 2: The Cell
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Cell structure and microscopyLight microscope, cell organelles, prokaryotic and eukaryotic cells.HLOL 16 q
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Cell diversity: tissues, organs and systemsHow cells specialise and are organised into tissues, organs and systems.HLOL 15 q
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Membranes, diffusion and osmosisMovement across membranes, turgor and plasmolysis.HLOL 16 q
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EnzymesHow enzymes work, factors affecting activity and immobilised enzymes.HLOL 21 q
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PhotosynthesisHow plants capture light energy to make glucose; light and dark stages.HLOL 20 q
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RespirationAerobic and anaerobic respiration, fermentation and bioprocessing.HLOL 18 q
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Cell continuity and cell divisionThe cell cycle, mitosis, meiosis and cancer.HLOL 16 q
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DNA, RNA and protein synthesisStructure of DNA, replication, profiling and how proteins are made.HLOL 18 q
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Genetics and inheritanceMendel's laws, monohybrid and dihybrid crosses, sex linkage.HLOL 23 q
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Variation, mutation and evolutionSources of variation, mutations, natural selection and evidence for evolution.HLOL 16 q
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Genetic engineeringSteps and applications of genetic modification and ethical issues.HLOL 16 q
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Chromosomes, non-nuclear inheritance and epigenetics (2025 spec)Chromosome structure (histones, chromatin, centromere), coding and non-coding DNA, mitochondrial and chloroplast DNA, and epigenetic control of gene expression. Added for the revised specification (students starting 5th year from September 2025).HLOL 15 q
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Cell proliferation and cancer (2025 spec)How loss of control of the cell cycle leads to cancer; risk factors (infectious agents, environment, genes), early detection, treatment, vaccination and lifestyle. Added for the revised specification (students starting 5th year from September 2025).HLOL 15 q
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DNA sequencing, bioinformatics and stem cells (2025 spec)The principle of DNA sequencing, using genome databases to find disease alleles, interpreting DNA profiles, stem cells and the ethics of genetic technologies. Added for the revised specification (students starting 5th year from September 2025).HLOL 15 q
Unit 3: The Organism
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Diversity of organisms and classificationThe five kingdoms and how organisms are classified.HLOL 15 q
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Monera (bacteria)Bacterial structure, reproduction, nutrition, growth curves and antibiotics.HLOL 17 q
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FungiRhizopus and yeast: structure, nutrition and reproduction.HLOL 15 q
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VirusesStructure, reproduction and diseases caused by viruses.HLOL 15 q
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Structure of the flowering plantRoots, stems, leaves, tissues and monocots versus dicots.HLOL 16 q
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Transport and nutrition in plantsWater uptake, transpiration, stomata and food storage.HLOL 18 q
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Plant responses and growth regulatorsTropisms, auxins and plant defences.HLOL 15 q
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Sexual reproduction in flowering plantsFlower structure, pollination, fertilisation, seeds, dispersal and germination.HLOL 18 q
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Vegetative propagationAsexual reproduction in plants and artificial propagation.HLOL 15 q
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Human nutrition and the digestive systemDigestion, absorption, enzymes and a balanced diet.HLOL 18 q
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Blood and the circulatory systemBlood composition, heart structure, blood vessels, blood pressure and lymphatic system.HLOL 20 q
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The breathing systemGas exchange, mechanism of breathing and its control.HLOL 16 q
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Excretion and homeostasisKidneys, skin, lungs and keeping internal conditions constant.HLOL 16 q
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The nervous system and sensesNeurons, synapses, reflex arcs, the brain, eye and ear.HLOL 18 q
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The endocrine systemHormones, glands and feedback control.HLOL 16 q
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The musculoskeletal systemBone, cartilage, joints, muscles and disorders.HLOL 16 q
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The human defence systemGeneral and specific defences, antibodies, vaccination and immunity.HLOL 16 q
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Human reproductionReproductive systems, menstrual cycle, fertilisation, development, birth and infertility.HLOL 18 q
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Domains of life and phylogeny (2025 spec)The three domains (Archaea, Bacteria, Eukarya), the six kingdoms, phylogenetic classification and why classification systems change with new evidence. Added for the revised specification (students starting 5th year from September 2025).HLOL 15 q
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Infectious and emerging diseases (2025 spec)Pathogen types, how diseases emerge and spread, the reproduction number R0, antimicrobial resistance and control strategies. Added for the revised specification (students starting 5th year from September 2025).HLOL 15 q