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NEB Grade 11 & 12 New Syllabus: Biology
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NEB Grade 11 & 12 Biology Syllabus — Complete Overview

Biology is one of the optional subjects available to Science stream students under the National Examination Board (NEB), Nepal, and is the primary subject for students planning careers in medicine, pharmacy, nursing, dentistry, agriculture, microbiology, biotechnology, and environmental science. The curriculum, developed by the Curriculum Development Centre (CDC), Sanothimi, Bhaktapur, under the National Curriculum Framework (NCF) 2076, divides Biology into two integrated sections — Botany (Part A) and Zoology (Part B) — each covered across both Grade 11 and Grade 12. Together, the two years build a comprehensive understanding of life at the molecular, cellular, organismal, and ecosystem levels, culminating in applied biology and human physiology in Grade 12.

This page provides a complete, unit-accurate breakdown of the NEB Biology syllabus for both grades, including exam structure and preparation strategy.

Subject Information at a Glance

  • Subject Name: Biology (Optional, Science Stream)
  • Subject Type: Optional (Science faculty) — most essential for medical/health science aspirants
  • Developed by: Curriculum Development Centre (CDC), Government of Nepal
  • Curriculum Framework: National Curriculum Framework (NCF) 2076, implemented from academic year 2077 BS
  • Structure: Two sections per grade — Botany (Part A) and Zoology (Part B)
  • Total Units: 10 units per grade (5 Botany + 5 Zoology)
  • Teaching Hours: 64 hours (Botany) + 64 hours (Zoology) = 128 teaching hours per grade
  • Total Full Marks: 75 (Theory) + 25 (Practical/Internal) = 100, per grade
  • Exam Duration: 3 hours (theory paper)

Why Biology Is Essential for Science Stream Students

Biology is the gateway subject for Nepal’s most competitive higher-education entrance examinations. The MECEE-BL (Medical Entrance Common Entrance Examination for Bachelor Level), which governs admissions to MBBS, BDS, BAMS, B.Pharm, BSc Nursing, and BVSc programs across Nepal, draws the majority of its questions from the NEB Grade 11 and 12 Biology syllabus. Students who thoroughly master these two years of Biology content have a direct, measurable advantage in entrance exam preparation. Beyond entrance exams, the subject develops a precise scientific vocabulary, strong diagram-drawing skills, and the analytical thinking needed for university-level biological sciences.

The NEB Biology curriculum is designed to build understanding at three levels: diversity and classification of living organisms (Grade 11), physiological and genetic mechanisms at the cellular and organ level (Grade 12), and applied biology connecting both to real-world issues like biotechnology, disease, conservation, and human health. Nepal-specific content — including vegetation types, protected areas, Ramsar sites, endangered species, and biodiversity hotspots of Nepal — is also explicitly included in both grades.

NEB Grade 11 Biology — Unit List with Topics

Grade 11 Biology covers 10 units across Botany and Zoology, totaling 128 teaching hours.

BOTANY — Part A (64 teaching hours)

Unit 1: Biomolecules and Cell Biology (15 teaching hours)

  • Biomolecules: introduction and functions of carbohydrates, proteins, lipids, nucleic acids, enzymes, minerals, and water
  • Cell: concepts of prokaryotic and eukaryotic cells; detailed structure of cell wall, cell membrane, mitochondria, plastids, endoplasmic reticulum, Golgi bodies, lysosomes, ribosomes, nucleus, chromosomes, cilia, and flagella
  • Cell division: cell cycle, amitosis, mitosis, meiosis, and their significance

Unit 2: Floral Diversity (30 teaching hours)

  • Classification: three domains, binomial nomenclature, five kingdom classification; status of flora in Nepal
  • Fungi: Phycomycetes, Ascomycetes, Basidiomycetes, Deuteromycetes; structure of Mucor and Yeast; mushrooms; economic importance
  • Lichen: introduction and economic importance
  • Algae: green, brown, red algae; Spirogyra structure and reproduction; economic importance
  • Bryophyta: liverworts, hornworts, mosses; morphology and reproduction of Marchantia
  • Pteridophyta: structure and reproduction of Dryopteris; economic importance
  • Gymnosperm: morphology and reproduction of Pinus; economic importance
  • Angiosperm: morphology (root, stem, leaf, inflorescence, flower, fruit, seed); taxonomic description of families — Brassicaceae, Fabaceae, Solanaceae, and Liliaceae with economic importance

Unit 3: Introductory Microbiology (5 teaching hours)

  • Monera: bacterial structure, modes of nutrition, bacterial growth; cyanobacteria
  • Virus: structure, importance, bacteriophage life cycle
  • Impacts of biotechnology in microbiology

Unit 4: Ecology (11 teaching hours)

  • Ecosystem ecology: biotic and abiotic factors, species interactions, pond and forest ecosystems, food chain and food web, trophic levels, ecological pyramids, productivity, carbon and nitrogen cycles, ecological succession
  • Ecological adaptation: hydrophytes and xerophytes
  • Ecological imbalances: greenhouse effect, climate change, ozone depletion, acid rain, biological invasion

Unit 5: Vegetation (3 teaching hours)

  • Types of vegetation in Nepal
  • In-situ conservation: national parks, wildlife reserves, protected areas
  • Ex-situ conservation: botanical gardens, seed banks

ZOOLOGY — Part B (64 teaching hours)

Unit 6: Introduction to Biology (2 teaching hours)

  • Scope and fields of biology
  • Relation of biology with other sciences

Unit 7: Evolutionary Biology (15 teaching hours)

  • Origin of life: Oparin-Haldane theory, Miller and Urey’s experiment
  • Evidences of evolution: morphological, anatomical, paleontological, embryological, biochemical
  • Theories of evolution: Lamarckism, Darwinism, Neo-Darwinism
  • Human evolution: position of man in animal kingdom, differences between new world monkeys, old world monkeys, apes and man; evolution of modern man from anthropoid ancestors

Unit 8: Faunal Diversity (34 teaching hours)

  • Protista: Protozoa classification up to class with examples; Paramecium caudatum and Plasmodium vivax and P. falciparum — habits, habitat, structure, reproduction, life cycle, and importance
  • Animalia: body plan, symmetry, body cavity, segmentation; phyla — Porifera, Cnidaria, Platyhelminthes, Aschelminthes, Annelida, Arthropoda, Mollusca, Echinodermata, and Chordata (classification up to class)
  • Earthworm (Pheretima posthuma): digestive, excretory (septal nephridia), nervous, and reproductive systems; cocoon formation
  • Frog (Rana tigrina): digestive system, blood vascular system (heart mechanism), respiratory system, reproductive system

Unit 9: Biota and Environment (10 teaching hours)

  • Animal adaptation: aquatic, terrestrial (cursorial, fossorial, arboreal), and volant adaptations
  • Animal behavior: reflex action, taxes, dominance, leadership; fish and bird migration
  • Pollution: air, water, soil — sources, effects, and control; effects of pesticides

Unit 10: Conservation Biology (3 teaching hours)

  • Biodiversity conservation: national parks, wildlife reserves, biodiversity hotspots, wetlands, Ramsar sites in Nepal
  • IUCN categories: extinct, endangered, vulnerable, rare; endangered species of Nepal

NEB Grade 12 Biology — Unit List with Topics

Grade 12 Biology also covers 10 units across Botany and Zoology, totaling 128 teaching hours. The content advances significantly from Grade 11, shifting from diversity and classification to physiology, genetics, and applied biology.

BOTANY — Part A (Grade 12)

Unit 1: Plant Anatomy (8 teaching hours)

  • Meristematic and permanent tissues
  • Anatomy of dicot and monocot root, stem, and leaf
  • Secondary growth in dicot stem

Unit 2: Plant Physiology (20 teaching hours)

  • Water relations: diffusion, osmosis, plasmolysis, ascent of sap, transpiration, guttation
  • Photosynthesis: photosynthetic pigments, photochemical phase, Calvin cycle, C3 and C4 plants, photorespiration, factors affecting photosynthesis
  • Respiration: glycolysis, Krebs cycle, electron transport system (ETS), factors affecting respiration
  • Plant hormones: auxins, gibberellins, cytokinins — physiological effects
  • Growth and movement: seed germination, dormancy, photoperiodism, vernalization, senescence; tropic and nastic movements

Unit 3: Genetics (21 teaching hours)

  • Genetic materials: structure of DNA and RNA, DNA replication, genetic code
  • Mendelian genetics: Mendel’s laws, incomplete dominance, co-dominance
  • Linkage and crossing over: complete and incomplete linkage, sex-linked inheritance (color blindness in humans, inheritance in Drosophila)
  • Mutation and polyploidy: gene mutation, chromosomal mutation, polyploidy and its significance

Unit 4: Embryology (8 teaching hours)

  • Asexual and sexual reproduction in angiosperms
  • Pollination and fertilization
  • Development of male and female gametophytes
  • Development of dicot and monocot embryos
  • Endosperm development

Unit 5: Biotechnology (7 teaching hours)

  • Tissue culture and plant breeding
  • Disease resistance, green manure, bio-fertilizers, biopesticides
  • Genetic engineering and genetically modified organisms (GMOs)
  • Bio-engineering and food safety

ZOOLOGY — Part B (Grade 12)

Unit 6: Animal Tissues (8 teaching hours)

  • Epithelial tissue: types, structure, function, location
  • Connective tissue: types, structure, function, location
  • Muscular tissue: types, structure, function
  • Nervous tissue: structure and function

Unit 7: Developmental Biology (6 teaching hours)

  • Gametogenesis: spermatogenesis and oogenesis
  • Frog development: fertilization, cleavage, blastulation, gastrulation, organogenesis (development of notochord, nerve cord, coelom)

Unit 8: Human Biology (28 teaching hours — largest unit)

  • Digestive system: structure of alimentary canal and digestive glands, physiology of digestion
  • Respiratory system: mechanism of breathing, gas exchange, transport of gases, regulation of respiration
  • Circulatory system: double circulation, structure of heart, cardiac cycle, ECG, blood grouping (ABO and Rh), blood pressure
  • Excretory system: ammonotelism, ureotelism, uricotelism; mechanism of urine formation
  • Nervous system: CNS, PNS, autonomic nervous system; structure of brain, nerve impulse conduction, synaptic transmission
  • Sense organs: structure and function of eye and ear
  • Endocrinology: hypothalamus, pituitary, thyroid, parathyroid, adrenal, pancreas, gonads; hypo- and hypersecretion disorders
  • Reproductive system: male and female reproductive organs, ovarian cycle, menstrual cycle

Unit 9: Human Population and Health Disorders (6 teaching hours)

  • Population growth: problems and control strategies, demographic cycle
  • Health disorders: cardiovascular disorders, respiratory disorders, renal disorders
  • Substance abuse: effects of drugs, alcohol, and smoking on health

Unit 10: Applied Biology (16 teaching hours)

  • Organ transplantation, IVF, amniocentesis, transgenic animals and GMOs, poultry and fish farming
  • Microbial diseases: Typhoid, Tuberculosis, HIV/AIDS, Cholera, Influenza, Hepatitis, Candidiasis — causative agents, symptoms, and prevention
  • Immunology: vaccines and vaccination, microbial contamination of water, sewage treatment, biocontrol agents, biofertilizers

NEB Biology Exam Structure

  • Theory Examination: 75 marks (3-hour written exam conducted by NEB)
  • Practical/Internal Evaluation: 25 marks (conducted by the school throughout the year)
  • Practical exams include microscopy, preparation of slides, dissection observations, ecological field visits, and project reports
  • NEB does not publish official unit-wise marks distribution; the CDC teaching-hour grid is explicitly for time distribution only

The theory paper typically includes objective questions (MCQs), short answer questions requiring precise definitions and labeled diagrams, and long answer questions requiring full system descriptions. Human Biology (Unit 8, Grade 12) consistently generates the highest number of long-answer questions given its 28 teaching hours. Genetics, Plant Physiology, Faunal Diversity, and Applied Biology also appear regularly across all question types.

Difference Between Grade 11 and Grade 12 Biology

Grade 11 Biology is primarily concerned with the diversity, classification, and ecology of living organisms. Botany covers biomolecules and cell biology, then works through the entire plant kingdom from fungi and algae to angiosperms, while Zoology introduces evolutionary biology, animal classification through all major phyla, the detailed anatomy of earthworm and frog, and conservation biology. Grade 12 Biology shifts fundamentally from classification to mechanism — how things work rather than what they are. Botany covers plant anatomy, detailed plant physiology (photosynthesis, respiration, hormones), genetics, embryology, and biotechnology. Zoology covers animal tissues, developmental biology, comprehensive human body systems, population health, and applied biology. Students often find Grade 12 Biology significantly more demanding due to the depth of Human Biology and Genetics.

Tips to Score High in NEB Biology Examination

  • Draw and label diagrams obsessively: Biology board exams heavily reward accurate, neatly labeled diagrams. Practice drawing the cell and its organelles, Marchantia thallus, Spirogyra, Pinus cone, earthworm internal anatomy, frog heart, dicot and monocot stem sections, human brain, human heart, nephron, eye, ear, and endocrine glands until you can reproduce them from memory in under 3 minutes each.
  • Master floral diversity for Grade 11: Unit 2 (Floral Diversity) carries the highest teaching hours in Grade 11 (30 hours) and generates a large proportion of short and long answer questions. Pay particular attention to the four angiosperm families (Brassicaceae, Fabaceae, Solanaceae, Liliaceae) and be able to write their diagnostic features and economic importance.
  • Prioritize Human Biology for Grade 12: With 28 teaching hours, Human Biology (Unit 8) is the largest single unit across both grades. All eight body systems — digestive, respiratory, circulatory, excretory, nervous, sense organs, endocrine, and reproductive — are testable in full detail, so thorough systematic study of each is essential.
  • Study Genetics with worked examples: Genetics (Unit 3, Grade 12) involves both conceptual understanding and problem-solving — working out monohybrid and dihybrid cross ratios, identifying incomplete dominance and co-dominance patterns, and solving sex-linked inheritance problems. Practice crosses using Punnett squares until the patterns become automatic.
  • Connect Applied Biology to real examples: Applied Biology (Unit 10, Grade 12) asks for specific disease information — causative agents, symptoms, prevention — for multiple diseases. Creating a concise comparison table for all seven diseases (Typhoid, Tuberculosis, HIV, Cholera, Influenza, Hepatitis, Candidiasis) is an efficient revision strategy.
  • Include Nepal-specific content in answers: The syllabus explicitly requires knowledge of Nepal’s vegetation types, national parks, wildlife reserves, Ramsar sites, biodiversity hotspots, and IUCN-listed endangered species of Nepal. Including these in relevant answers demonstrates curriculum awareness and often earns extra marks.
  • Maintain your practical file carefully: The 25-mark practical evaluation covers microscopy, slide preparation, dissection observations, field visit reports, and project work. A complete, well-organized practical notebook directly secures marks that don’t depend on exam-day performance.
  • Review past NEB Biology question papers: Board exam questions recur from specific sub-topics — particularly earthworm excretory system, Plasmodium life cycle, Mendelian ratios, photosynthesis light reactions, cardiac cycle, urine formation, endocrine disorders, and transgenic organisms.

Frequently Asked Questions (FAQs)

How many units are there in NEB Biology for Grade 11 and Grade 12?

Both Grade 11 and Grade 12 Biology have 10 units each — 5 Botany units and 5 Zoology units — totaling 128 teaching hours per grade.

What is the difference between Botany and Zoology in NEB Biology?

Botany (Part A) covers the biology of plants, fungi, algae, and microorganisms, including their structure, reproduction, physiology, genetics, and biotechnology. Zoology (Part B) covers the biology of animals, including classification, anatomy of specific organisms (earthworm, frog), human body systems, evolutionary biology, and conservation. Both sections are equally important and are tested together in the same theory paper.

Which NEB Biology unit has the most teaching hours?

In Grade 11, Faunal Diversity (Unit 8 / Zoology) has the most teaching hours at 34 hours, followed by Floral Diversity (Unit 2 / Botany) at 30 hours. In Grade 12, Human Biology (Unit 8 / Zoology) has the most at 28 teaching hours, followed by Genetics (Unit 3 / Botany) at 21 hours and Plant Physiology (Unit 2 / Botany) at 20 hours.

Is Biology compulsory for the medical entrance exam in Nepal?

Yes. Biology is the core subject tested in the MECEE-BL (Medical Entrance Common Entrance Examination for Bachelor Level), which governs admissions to MBBS, BDS, BAMS, B.Pharm, BSc Nursing, and BVSc programs. Almost all MECEE Biology questions are drawn directly from the NEB Grade 11 and 12 Biology syllabus.

Which angiosperm families are included in the NEB Grade 11 Biology syllabus?

The NEB Grade 11 Biology syllabus includes four angiosperm families under floral diversity: Brassicaceae (mustard family), Fabaceae (legume family), Solanaceae (nightshade family), and Liliaceae (lily family) — each with diagnostic features and economic importance.

Does NEB publish official unit-wise marks distribution for Biology?

No. The official CDC syllabus document explicitly states that the teaching-hour grid is for time distribution purposes only and that marks should not be assigned to it. Students should prepare across all 10 units per grade proportionally, weighted toward high-teaching-hour units.

Where can I find Biology notes and important questions for Grade 11 and 12?

You can find Biology study resources on nneducation.com. Browse our courses from the Courses section. The official syllabus PDF is also embedded at the top of this page for your reference.

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