AIIMS Biology Syllabus 2025 – Detailed Chapters, Weightage & Preparation Tips

UNIT 1: Diversity in Living World

• What is living? ; Biodiversity; Need for classification;; Taxonomy & Systematics; Concept of species and taxonomical hierarchy; Binomial nomenclature; 

• Five kingdom classifications; salient features and classification of Monera; Protista and Fungi into major groups; Lichens; Viruses and Viroids. 

• Salient features and classification of plants into major groups-Algae, Bryophytes, Pteridophytes, Gymnosperms (three to five salient and distinguishing features and at least two examples of each category); 

• Salient features and classification of animals-nonchordate up to phyla level and chordate up to classes level (three to five salient features and at least two examples).

UNIT 2: Structural Organisation in Animals and Plants

• Morphology and modifications; Tissues; Anatomy and functions of different parts of flowering plants: Root, stem, leaf, inflorescence- cymose and recemose, flower, fruit and seed (To be dealt along with the relevant practical of the Practical Syllabus) Family (malvaceae, Cruciferae, leguminoceae, compositae, graminae).

• Animal tissues; Morphology, anatomy and functions of different systems (digestive, circulatory, respiratory, nervous and reproductive) of an insect (Frog). (Brief account only)

UNIT 3: Cell Structure and Function

• Cell theory and cell as the basic unit of life; Structure of prokaryotic and eukaryotic cell; Plant cell and animal cell; Cell envelope, cell membrane, cell wall; Cell organellesstructure and function; Endomembrane system-endoplasmic reticulum, Golgi bodies, lysosomes, vacuoles; mitochondria, ribosomes, plastids, micro bodies; Cytoskeleton, cilia, flagella, centrioles (ultra structure and function); Nucleus-nuclear membrane, chromatin, nucleolus. 

• Chemical constituents of living cells: Biomolecules-structure and function of proteins, carbodydrates, lipids, nucleic acids; Enzymes-types, properties, enzyme action, classification and nomenclature of anzymes.

• B Cell division: Cell cycle, mitosis, meiosis and their significance.

UNIT 4: Plant Physiology

• Photosynthesis: Photosynthesis as a means of Autotrophic nutrition; Site of photosynthesis take place; pigments involved in Photosynthesis (Elementary idea); Photochemical and biosynthetic phases of photosynthesis; Cyclic and non cyclic and photophosphorylation; Chemiosmotic hypothesis; Photorespiration C3 and C4 pathways; Factors affecting photosynthesis.

• Respiration: Exchange gases; Cellular respiration-glycolysis, fermentation (anaerobic), TCA cycle and electron transport system (aerobic); Energy relations- Number of ATP molecules generated; Amphibolic pathways; Respiratory quotient. 

• Plant growth and development: Seed germination; Phases of Plant growth and plant growth rate; Conditions of growth; Differentiation, dedifferentiation and redifferentiation; Sequence of developmental process in a plant cell; Growth regulatorsauxin, gibberellin, cytokinin, ethylene, ABA; 

UNIT 5: Human Physiology

• Breathing and Respiration: Respiratory organs in animals (recall only); Respiratory system in humans; Mechanism of breathing and its regulation in humans-Exchange of gases, transport of gases and regulation of respiration Respiratory volumes; Disorders related to respiration-Asthma, Emphysema, Occupational respiratory disorders.

• Body fluids and circulation: Composition of blood, blood groups, coagulation of blood; Composition of lymph and its function; Human circulatory system-Structure of human heart and blood vessels; Cardiac cycle, cardiac output, ECG, Double circulation; Regulation of cardiac activity; Disorders of circulatory system-Hypertension, Coronary artery disease, Angina pectoris, Heart failure.

• Excretory products and their elimination: Modes of excretion- Ammonotelism, ureotelism, uricotelism; Human excretory system-structure and fuction; Urine formation, Osmoregulation; Regulation of kidney function-Renin-angiotensin, Atrial Natriuretic Factor, ADH and Diabetes insipidus; Role of other organs in excretion; Disorders; Uraemia, Renal failure, Renal calculi, Nephritis; Dialysis and artificial kidney.

• Locomotion and Movement: Types of movement- ciliary, fiagellar, muscular; Skeletal muscle- contractile proteins and muscle contraction; Skeletal system and its functions (To be dealt with the relevant practical of Practical syllabus); Joints; Disorders of muscular and skeletal system-Myasthenia gravis, Tetany, Muscular dystrophy, Arthritis, Osteoporosis, Gout.

• Neural control and coordination: Neuron and nerves; Nervous system in humanscentral nervous system, peripheral nervous system and visceral nervous system; Generation and conduction of nerve impulse;

• Chemical coordination and regulation: Endocrine glands and hormones; Human endocrine system-Hypothalamus, Pituitary, Pineal, Thyroid, Parathyroid, Adrenal, Pancreas, Gonads; Mechanism of hormone action (Elementary Idea); Role of hormones as messengers and regulators, Hypo-and hyperactivity and related disorders (Common disorders e.g. Dwarfism, Acromegaly, Cretinism, goiter, exopthalmic goiter, diabetes, Addison’s disease).

(Imp: Diseases and disorders mentioned above to be dealt in brief)

UNIT 6: Reproduction

• Sexual reproduction in flowering plants: Flower structure; Development of male and female gametophytes; Pollination-types, agencies and examples; Outbreeding devices; Pollen-Pistil interaction; Double fertilization; Post fertilization events- Development of endosperm and embryo, Development of seed and formation of fruit; Special modesapomixis, parthenocarpy, polyembryony; Significance of seed and fruit formation. 

• Human Reproduction: Male and female reproductive systems; Microscopic anatomy of testis and ovary; Gametogenesis-spermatogenesis & oogenesis; Menstrual cycle; Fertilisation, embryo development upto blastocyst formation, implantation; Pregnancy and placenta formation (Elementary idea); Parturition (Elementary idea); Lactation (Elementary idea). 

• Reproductive health: Need for reproductive health and prevention of sexually transmitted diseases (STD); Birth control-Need and Methods, Contraception and Medical Termination of Pregnancy (MTP); Amniocentesis; Infertility and assisted reproductive technologies – IVF, ZIFT, GIFT (Elementary idea for general awareness).

UNIT 7: Genetics and Evolution

• Heredity and variation: Mendelian Inheritance; Deviations from MendelismIncomplete dominance, Co-dominance, Multiple alleles and Inheritance of blood groups, Pleiotropy; Elementary idea of polygenic inheritance; Chromosome theory of inheritance; Chromosomes and genes; Sex determination-In humans, birds, honey bee; Linkage and crossing over; Sex-linked inheritance-Haemophilia, Colour blindness; Mendelian disorders in humans-Thalassemia; Chromosomal disorders in humans; Down’s syndrome, Turner’s and Klinefelter’s syndromes.

• Molecular basis of Inheritance: Search for genetic material and DNA as genetic material; Structure of DNA and RNA; DNA packaging; DNA replication; Central dogma; Transcription, genetic code, translation; Gene expression and regulation- Lac Operon; Genome and human genome project; DNA finger printing, protein biosynthesis.

• Evolution: Origin of life; Biological evolution and evidence for biological evolution from Paleontology, comparative anatomy, embryology and molecular evidence); Darwin’s contribution, Modern Synthetic theory of Evolution; Mechanism of evolution Variation (Mutation and Recombination) and Natural Selection with examples, types of natural selection; Gene flow and genetic drift; Hardy-Weinberg’s principle; Adaptive Radiation; Human evolution.

UNIT 8: Biology and Human Welfare

• Health and Disease; Pathogens; parasites causing human diseases (Malaria, Filariasis, Ascariasis. Typhoid, Pneumonia, common cold, amoebiasis, ring worm, dengue, chikungunya); Basic concepts of immunology-vaccines; Cancer, HIV and AIDS; Adolescence, drug and alcohol abuse.Tobacco abuse.

• Microbes in human welfare: In household food processing, industrial production, sewage treatment, energy generation and as biocontrol agents and biofertilisers.

UNIT 9: Biotechnology and Its Applications

• Principles and process of Biotechnology: Genetic engineering (Recombinant DNA technology).

• Application of Biotechnology in health and agriculture: Human insulin and vaccine production, gene therapy; Genetically modified organisms-Bt crops; Transgenic Animals; Biosafety issues-Biopiracy and patents.

UNIT 10: Ecology and Environment

• Organisms and environmentPopulation interactions-mutualism, competition, predation, parasitism; Population attributes-growth, birth rate and death rate, age distribution. 

• Ecosystem: Patterns, components; productivity and decomposition; Energy flow; Pyramids of number, biomass, energy.

• Biodiversity and its conservation: Concept of Biodiversity; Patterns of Biodiversity; Importance of Biodiversity; Loss of Biodiversity; Biodiversity conservation; Hotspots, endangered organisms, extinction, Red Data Book, biosphere reserves, National parks and sanctuaries, Sacred Groves.

Biology Important Chapters for AIIMS 2025

Weightage

Human Physiology

20%

Diversity of the Living World

14%

Structural Organisation in Animals and Plants

9%

Plant Physiology

6%

Cell Structure and Function

5%

Genetics and Evolution

18%

Ecology and Environment 

12%

Reproduction

9%

Biology in Human Welfare

4%

Biotechnology and Its Applications

3%

Important Topics of Class 11 Biology Syllabus for AIIMS

Chapter

Important Topics

Plant Kingdom

Types of algae and their pigments

General characters of pteridophytes and gymnosperms

Biological classification

General features of Monera, Protista, Fungi

Structural Organization in Plants and Animals

Root, stem, and leaf anatomy

Animal tissues and their functions, specifically epithelial tissues

Cell: Structure & Functions

Mycoplasma, nucleus, chromosomes, ribosomes, chloroplast, and mitochondria

Meiosis – Prophase I

Plant Physiology

C3, C4 cycle

Kranz anatomy

Glycolysis and Krebs cycle

ETS complexes

Photoperiodism

Transpiration pull

Bulk movement in Phloem

Mineral deficiency & Nitrogen cycle

Animal/Human Physiology

All topics specifically diagrams are very important

Important Topics of AIIMS Biology Syllabus Class 12

Chapter

Important Topics

Reproduction

Gametogenesis in plants

Gametogenesis in humans

Reproductive structures in plants and animals

Polyembryony, Parthenocarpy, apomixis

Menstrual cycle

Genetics & Evolution

Dihybrid cross, linkage

Codominance

Pedigree analysis

Genetic disorders

Darwinism and natural selection

Human evolution

Biotechnology

Process and applications

BT cotton, RNAi, Human insulin, Gene therapy, molecular diagnostics

Biology in Human Welfare

Human immunity

AIDS, Cancer

Drugs

Ecology and Environment

Environmental issues

Biogeochemical cycles

Population interactions

Adaptations

Succession

Unit Name

Deleted Syllabus Topics

Diversity in Living World

- Three domains of life

- Tools for the study of Taxonomy — Museums, Zoos, Herbaria, Botanical gardens

- Angiosperms classification up to class, characteristic features, and examples

Structural Organization in Animals and Plants

- Morphology, anatomy, and functions of different systems (digestive, circulatory, respiratory, nervous, and reproductive) of an insect (cockroach). (Brief account only)

Plant Physiology

- Transport in plants: Movement of water, gases, and nutrients; Cell-to-cell transport — Diffusion, facilitated diffusion, active transport

- Plant-water relations — Imbibition, water potential, osmosis, plasmolysis

- Long-distance transport of water — Absorption, apoplast, symplast, transpiration pull, root pressure, and guttation

- Transpiration — Opening and closing of stomata; Uptake and translocation of mineral nutrients — Transport of food, phloem transport, Mass flow hypothesis

- Diffusion of gases (brief mention)

- Mineral nutrition: Essential minerals, macro and micronutrients and their role; Deficiency symptoms; Mineral toxicity

- Elementary idea of Hydroponics as a method to study mineral nutrition

- Nitrogen metabolism — Nitrogen cycle, biological nitrogen fixation

- Seed dormancy; Vernalisation; Photoperiodism

Human Physiology

- Digestion and absorption; Alimentary canal and digestive glands; Role of digestive enzymes and gastrointestinal hormones

- Peristalsis, digestion, absorption, and assimilation of proteins, carbohydrates, and fats

- Caloric value of proteins, carbohydrates, and fats

- Egestion; Nutritional and digestive disorders — PEM, indigestion, constipation, vomiting, jaundice, diarrhea

S. No

Subject-wise Links for AIIMS Syllabus

1.

AIIMS Physics Syllabus 2025

2.

AIIMS Chemistry Syllabus 2025

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Study Materials Links

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