Biology Science (English Medium) Class 11 CBSE Syllabus 2025-26

• What is ‘Living’?
• Characteristics of living organisms

1. Growth
2. Reproduction
3. Cellular structure
4. Response to stimuli (Consciousness)
5. Homeostasis
6. Metabolism

• Difference  between anabolism and catabolism

• Diversity in the Living World
• Biodiversity
• Types of Biodiversity

1. Genetic Biodiversity
2. Species Biodiversity
3. Ecological Biodiversity

• Biodiversity
• Identification
• Nomenclature - Binomial Nomenclature
• Classification - Taxonomy and Systematics

• Taxonomical Aids
• Usage of Taxonomical Aids

1. Herbarium
2. Botanical Gardens
3. Biological museums
4. Zoological Parks
5. Key
6. Molecular taxonomy
7. Automated species identification tools

• Introduction
• Classification and Evolution of Diversity in Living Organisms
• Classification of Living Things

• History of Classification

• Aristotle
• Theophrastus
• John Ray
• Carolus Linnaeus
• Ernst Haeckal
• Herbert F. Copeland
• R.H.Whittaker
• Carl Woese

• Introduction
• Hierarchy Classification
• Five Kingdom Classification

• Introduction
• Experiment

• Introduction
• Experiment

• Introduction
• Experiment

• Structure of Fungi

• Spores
• Yeast
• Mould

• Life processes in Fungi: Nutrition

• Parasites
• Saprophytes
• Symbionts

• Kingdom Animalia
• Characteristics of Kingdom Animalia

• Structure and Function of Viruses

• Bacteriophage
• Tobacco mosaic virus
• HIV

• Kingdom Animalia
• Characteristics of Kingdom Animalia

• Levels of organisation

• Cellular level of organisation
• Tissue level of organisation
• Organ system level of organisation

• Diploblastic and Triploblastic organisation
• Patterns of symmetry
• Coelom
• Segmentation and Notochord

• Parazoa
• Eumetazoa

1. Radiata
2. Bilateria

• Division 1: Protostomia
• Division 2: Deuterostomia 

• Non Chordates (Invertebrata)
• Chordates 

• Chordata: Prochordata
• Chordata: Vertebrata

• Comparison of chordates and non-chordates

• Plant morphology
• Classification of plant morphology

1. Vegetative morphology
   Component of vegetative morphology
   (a) Habit
   (b) Plant habitat
   (c) Life Span
2. Reproductive Morphology

• Parts of a flowering plant

• Root system
• Characteristic of the root system
• Type of Root:
  1) Primary root
  2) Secondary root
• Regions of root
  1) Meristematic Zone
  2) Zone of Elongation
  3) Zone of Maturation
• Types of the root system
  1) Tap root system
  2) Fibrous root system
  3) Adventitious root system
• Functions of root
  1) Primary function
  2) Secondary function
• Modifications of root

• The Leaf
• Characteristics of leaf
• Functions of the leaf -
  1) Primary functions
  2) Secondary functions
• Parts of the leaf -
  1) Leaf base (hypopodium)
  2) Petiole (stipe or mesopodium)
  3) Lamina (Leaf blade)
• Venation -
  1) Reticulate venation
  2) Parallel venation
• Phyllotaxy -
  1) Alternate Phyllotaxy
  2) Opposite Phyllotaxy
  3) Ternate phyllotaxy
  4) Whorled (verticillate) type of phyllotaxy
• Leaf mosaic
• Types of Leaves -
  1) Simple leaf
  2) Compound leaf - Pinnately and palmately compound leaf
• Modifications of Leaves
  1) Leaf tendrils
  2) Leaf hooks
  3) Leaf Spines and Prickles
  4) Storage Leaves
  5) Phyllode
  6) Pitcher
  7) Bladder
  8) Floral leaves
• Leaf duration - Caducuous (Fagacious), Deciduous, Evergreen and Marcescent

• The steam
• Characteristic features of the stem
• Functions of the stem
  (i) Primary functions
  (ii) Secondary functions
• Buds
• Types of Stem - Excurrent, Decurrent, Caudex, and Culm
• Modification of Stem
  1) Aerial modification of stem
  2) Subaerial stem modifications
  3) Underground stem modifications
  4) Stem Branching

• Inflorescence
• Types of Inflorescence
  1) Based On Position - Terminal, Auxillary, and Cauliflorous
  2) Based on branching pattern and other characters -Indeterminate (Racemose), Determinate (Cymose), Mixed inflorescence and Special inflorescence
• Racemose Inflorescence
  1) Main axis elongated - Simple raceme, Spike, Spikelet, Catkin, Spadix and Pancile
  2) Main axis shortened - Corymb, Umbel
  3) Main axis flattened - Head, 
• Cymose inflorescence - 
  1) Simple cyme (solitary)
  2) Monochasial Cyme (uniparous) - Helicoid and Scorpioid
  3) Simple dichasium (Biparous)
  4) Compound dichasium:
  5) Polychasial Cyme (multiparous)
• Mixed Inflorescence
  1) Thyrsus
  2) Verticillaster
• Special Inflorescence
  1) Cyathium
  2) Hypanthodium
  3) Coenanthium

• Flower
• Whorls of flower - Complete and Incomplete
• Flower sex 
  1) Perfect or bisexual
  2) Imperfect or unisexual: Staminate and Pistillate flowers
• Plant sex
  1) Hermaphroditic
  2) Monoecious
  3) Dioecious
  4) Polygamous
• Flower symmetry
  1) Actinomorphic (or) radial or polysymmetric
  2) Zygomorphic (bilateral symmetry) or monosymmetric
  3) Asymmetric (amorphic)
• Types of Flower
  1) Types of flower depending upon the number of floral appendages
  i) Trimerous
  ii) Tetramerous
  iii) Pentamerous
  2) Types of flowers depending on presence of bracts
  i) Bracteate
  ii) Ebracteate
  3) Types of flower based on the position of calyx, corolla and androecium in respect of the ovary on thalamus
  i) Hypogynous
  ii) Perigynous
  iii) Epigynous

• The Fruits - Pomology
• Structure of Fruit - Pericarp, epicarp, mesocarp, endocarp.
• Types of Fruits
  1) Simple fruits
  a) Fleshy Fruit
  b) Dry Fruit
  2) Aggregate Fruit
  3) Multiple Fruit
• Parts of a typical fruit
  a) Pericarp
  b) Seeds
  c) Drupe
• Function of Fruits

• The seed
• Types of seed
  A) Based on the number of cotyledons two types of seeds are recognized.
  (i) Dicotyledonous seed
  (ii) Monocotyledonous seed
  B) Based on the presence or absence of the endosperm the seed is of two types. 
  (i) Albuminous or Endospermous seed
  (ii) Ex-albuminous or non- endospermous seed
• Significance of Seeds

Anatomy and functions of different parts of flowering plants: root, stem, leaf, inflorescence, flower, fruit and seed (to be dealt along with the relevant experiment of the Practical Syllabus).

• Introduction
• Differences Between Plant and Animal Tissues

• Introduction
• Types of Meristematic Tissue

• Earthworms
• Classification of earthworm
• Economic importance of earthworm

• The Fundamental Unit of Life: Cell
• Discovery of Cells

• Cell theory and cell as the basic unit of life
• Exception to Cell Theory 
• Protoplasm Theory
• Cell sizes and shapes

• Cell Numbers
• Cell Size
• Smallness of Cells: A Greater Efficiency
• Cell Shapes: To suit Functional Requirement

• The acid-soluble pool (Filtrate)
• Types of Biomolecules

1. Micromolecules
2. Macromolecules

• Proteins
• Based on our nutritional requirements, amino acids are classified as:
  1) Non-essential amino acids 
  2) Essential amino acids
• Functions of proteins
• Bonding and protein structure
  1) Peptide bond of proteins or polypeptides
• Classification of proteins
  1) Primary (Basic) structures
  2) Secondary structure
  3) Tertiary structure
  4) Quaternary structure
• Amino acids

Structure and Function of Proteins

amino acids – (structure: glycine, alanine, serine)

amino acids as zwitter-ion

examples of acidic, basic, neutral, sulphur containing amino acids

essential and nonessential amino acids

levels of protein structure (primary, secondary, tertiary and quaternary)

functions of proteins

1. Purely proteinaceous enzymes
2. Conjugated enzymes

• Carbohydrates
• Classification of carbohydrates

classification, structure and functions of fats and oils

• Amitosis (Direct Cell Division)
• Mitosis
• Closed and Open Mitosis
• Cytokinesis
• Significance of Mitosis
• Meiosis

• Meiosis I-Reduction Division

• Significance of Meiosis

• Phases of cell cycle

1. Interphase
   1) G₁ phase (Gap 1): Quiescent stage or G₀ Phase
   2) S phase (Synthesis)
   3) G₂ phase (Gap 2)
2. Mitosis or M-phase

• Meiosis I or reduction division
• Stages of Meiosis: Interphase and Karyokinesis
  i) Interphase
  ii) Karyokinesis
  a) Prophase I: Leptotene, Zygotene, Pachytene, Diplotene, Diakinesis
  b) Metaphase I
  c) Anaphase I
  d) Telophase I
• Cytokinesis
• Interkinesis

• Meiosis II
• Phases of Meiosis II

1. Karyokinesis
   a) Prophase II
   b) Metaphase II
   c) Anaphase II
   d) Telophase II
2. Cytokinesis II

• Passive Transport

• Characteristics of diffusion
• Significance of diffusion in Plants

1. Channel Protein
2. Carrier Protein

• Active Transport

• Water Potential (ψ)
• Factors affecting water absorption

• Opening and Closing of Stoma

• Priestley's experiment

• Light Reactions
• Dark Reaction

• difference between chlorophyll ‘a’&‘b’, carotenoids and xanthophyll
• Pigments Involved in Photosynthesis (Elementary Idea)

• Photoexcitation of PS-II
• Electron transport system
• Photoexcitation of PS-I
• The Z-Scheme

• Photophosphorylation

1. Non-cyclic photophosphorylation
2. Cyclic Photophosphorylation

• C₄ Plants
• Characteristics of C₄ plants
• Kranz Anatomy
• The C₄ Pathway
• Diagramatic representation of the Hatch and Slack pathway

• Blackman - Law of limiting factors
• Factors affecting photosynthesis

1. External Factors:
   1) Availability of sunlight
   2) Temperature
   3) Water
   4) Humidity
   5) CO₂ Concentration [atmospheric]
   6) O₂ availability
2. Internal Factors:
   1) Number of leaves
   2) Size of leaves
   3) Leaf age
   4) Orientation of leaves
   5) Mesophyll cells and chloroplasts
   6) Internal CO₂ concentration
   7) Anatomy of leaf

C3 and C4 pathways

• Glycolysis
• Glycolysis Pathway

• Fermentation
• Process of Fermentation
• Types of Fermentation

1. Lactic Acid Fermentation
2. Alcohol Fermentation
3. Acetic acid Fermentation
4. Butyric acid Fermentation

• Advantages of Fermentation

• Cellular respiration
• Types of cellular respiration

1. Aerobic Respiration
2. Anaerobic Respiration

• Aerobic respiration in plant/animal
• Anaerobic respiration in plant/animal
• Differences in anaerobic respiration in plants and animals

• TCA Cycle (Tricarboxylic Acid Cycle)
• Steps of TCA Cycle

• Oxidative Phosphorylation
• Oxidative Phosphorylation Steps

• Do plants breathe?
• The process of respiration in plants
• Respiration in roots
• Respiration in stems
• Respiration in leaves
• Types of respiration

1. Aerobic Respiration
2. Anaerobic Respiration

• Sources of minerals
• Classification of minerals on the basis of their quality requirement:

1. Essential minerals 
2. Non-essential minerals 

• Classification of minerals on the Basis of their quantity requirement:

1. Microelement minerals
2. Macroelement minerals

• Symptoms of Mineral deficiency in plants
• Toxicity of Micronutrients
• Minerals salt absorption: Passive Absorption and Donnan equilibrium

• Hydroponics

• Characteristics of Growth in plants:
  1) Indeterminate or continuous growth
  2) Localised growth

• Phases of Plant Growth

1. Phase of cell division/ formation (Meristematic Phase)
2. Phase of cell enlargement/ elongation (Elongation Phase)
3. Phase of Cell maturation/ differentiation (Maturation Phase)

• Growth Rates
  1) Arithmetic growth
  2) Geometric growth

• Sequence of Developmental Processes in a Plant Cell

• Photoperiodism

1. Short Day Plants (SDP)
2. Long Day Plants (LDP)
3. Day Neutral Plants (DNP)

• Phytochrome

• Vernalisation
• Kinds of varieties
  1) Spring variety
  2) Winter variety

• Immediate Response to Stimulus
• Movement Due to Growth

1. Phototropism
2. Geotroplsm
3. Hydrotroplsm
4. Thigmotropism
5. Chemotropism

• Process of Seed and Fruit Development  
• Significance of seed and fruit formation
• Dormancy

• Respiratory Organs in Animals
• gills, lungs

• Respiratory System
• Exchange of Gases in Lungs
• Significance of Respiration

1. Tidal Volume (TV)
2. Inspiratory Reserve Volume (IRV)
3. Expiratory Reserve Volume (ERV)
4. Residual Volume (RV)
5. Inspiratory Capacity (IC)
6. Expiratory Capacity (EC)
7. Functional Residual Capacity (FRC)
8. Vital Capacity (VC)
9. Total Lung Capacity (TLC)

• Exchange of Gases - in Humans

• Neural control
  1) Respiratory rhythm centre
  2) Pneumotaxic centre
• Chemical Control
  1) Chemosensitive Area
  2) Chemoreceptors

Disorders of the respiratory system

• Emphysema
• Chronic bronchitis
• Acute bronchitis
• Sinusitis
• Laryngitis
• Pneumonia
• Asthma
• Occupational Respiratory Disorderssilicosis, asbestosis

• Human Blood Groups
• Rh Factor
• Blood Donation
• Blood Banks
• Blood Donor
• Blood Recipient

• Clotting of Blood (Coagulation)
• Blood clotting in a test tube

• Lymph and Lymphatic System
• Composition of Lymph
• Functions of Lymph

• Types of Closed Circulation:

1. Single circulation
2. Double circulation
   - Systemic circulation
   - Pulmonary circulation
   - Coronary circulation

• Hepatic Portal System

• Disorders of the Circulatory System:

1. Hypertension/ High blood pressure: Normal blood pressure
2. Coronary Artery Disease (CAD) or Atherosclerosis
3. Angina / Angina pectoris
4. Heart Failure: Myocardial infarction (Heart failure), Cardiac arrest, Heart attack, Stroke
5. Rheumatoid Heart Disease

• Introduction
• Human Excretory System Organs
• Excretion in Humans
• Mechanism of Excretion in Humans
• Dialysis

• Ultrafiltration
• Reabsorption
• Tubular secretion (Renal Secretion)
• Distal convoluted tubule (DCT)
• Collecting duct

• Proximal Convoluted Tubule (PCT)
• Henle’s Loop, Distal Convoluted Tubule (DCT)

• Osmoregulation
• Regulation of Kidney Function

1. Renin-Angiotensin,
2. Atrial Natriuretic Factor (ANF)
3. ADH and Diabetes Inspidus

• Urine

• Excretory role of skin
• Excretory role of lungs
• Excretory role of liver

• Kidney stones
• Uremia
• Nephritis
• Renal Failure
• Diabetes
• Urinary tract infection
• Haemodialysis
• Peritoneal dialysis 
• Kidney transplant
• Renal Calculi
• Glomerulonephritis

• Modes of Excretion

1. Ammonotelism
2. Ureotelism 
3. Uricotelism 

• Nephridiopores
• Types of nephridia

1. Protonephridia
2. Metanephridia

• Dialysis
• Types of Dialysis

• Alimentary canal
• The human alimentary canal consists following parts:

1. Buccal (oral) cavity
   a) Mouth
   b) Teeth - thecodont, Diphyodont, enamel, Types of Teeth: Incisors, Canines, Premolars, Molars, Dental Formula → Arrangement of teeth in each half of the upper and lower jaw
   c) Tongue
2. Pharynx
3. Oesophagus (food pipe)
4. Stomach: Cardiac region, Fundic region, Body (Main central region), Pyloric region.
5. Small Intestine: Duodenum, Jejunum, IIleum
6. Large Intestine: Caccum, Colon, Rectum, Anal canal
7. Anus: Wall of Alimentary canal
   i) Serosa
   ii) Muscularis
   iii) Submucosa
   iv) Mucosa

• Digestive Glands

1. Salivary gland:
   a) Parotid gland
   b) Subligual gland
   c) Submaxillary/ Submandibular gland
2. Liver
3. Gall bladder
4. Pancreas

• Absorption of substances takes place in different parts of the alimentary canal, like mouth, stomach, small intestine and large intestine

• Disorders of the digestive system

1. Inflammation of the intestinal tract
2. Jaundice
3. Vomiting 
4. Diarrhoea
5. Constipation
6. Indigestion

• PEM (Protein-energy malnutrition)

1. Kwashiorkar
2. Marasmus

• In Buccal Cavity: Constituents of saliva, Salivary amylase, Lysozyme
• In Stomach:
  a) Gastric glands: Chief/ peptic (zymogen cells), Oxyntic/ parietal cells, Mucus neck cells, Gastric Juice, gastric secretion
• In Small Intestine: Intestinal juice (Succus entericus)
  a) Role of bite in fat digestion
  b) Role of Pancreatic Juice
  ⇒ In carbohydrate digestion
  ⇒ In protein digestion
  ⇒ In fat digestion
  ⇒ In Nucleic acid digestion
  c) Role of intestinal juice indigestion
  ⇒ In carbohydrate digestion
  ⇒ In protein digestion
  ⇒ In fat digestion
  ⇒ In Nucleic acid digestion
• Large Intestine
  ⇒ Neural and hormonal control on digestion process

• Absorption
• It is carried out by various processes:

1. Passive Absorption
   ⇒ Process
   a) Simple diffusion
   b) Osmosis
   c) Facilitated transport
2. Active absorption

• Absorption of fatty acids and glycerol
• Absorption in different parts of the alimentary canal
• Assimilation

• Movements
• Locomotion
• Locomotary movements
• Significance of locomotion

• Types of movement
  1) Amoeboid movement
  2) Ciliary movement
  3) Muscular movement

• Muscles
• Properties of muscles
• Classification of muscles

1. Based on their location
   (i) Skeletal muscles
   (ii) Visceral muscles
   (iii) Cardiac muscles
2. Based on their appearance
   (i) Striated muscles
   (ii) Smooth muscles
3. Based on nature
   (i) Voluntary muscles
   (ii) Involuntary muscles

• Structure of Contractile Proteins

1. Actin filament
2. Myosin filament

• Mechanism of muscle contraction
• Steps of muscle contraction

• Skeletal System and Its Functions

• Disorders of Muscular and Skeletal System -

1. Myasthenia gravis
2. Tetany
3. Muscular dystrophy
4. Arthritis
5. Osteoporosis
6. Gout

• Central Nervous System
• Different regions of Brain and its functions

• Reflexes
• Types of actions

1. Voluntary actions 
2. Involuntary actions

• Sense Organs (Receptors)
• Olfactory receptors
• Gustatory receptors
• Classification of Receptors
  (i) Thermoreceptors
  (ii) Tactile receptors / Tangoreceptors
  (iii) Chemoreceptors
  (iv) Phonoreceptors
  (v) Statoreceptors
  (vi) Photoreceptors
  (vii) Pain receptors / Nociceptors
  (viii) Proprioceptors

• Structure and Components
• Photoreceptors and Eye Muscles

• Structure of Human Ear
• Function of Human Ear

Human Endocrine System

• Properties of Hormones 
• Mechanism of hormone action 

• Hormones are also secreted by some tissues which are not endocrine glands:
  1) Heart
  2) Kidney
  3) Gastro-intestinal tract: Gastrin, Secretin, Cholecystokinin (CCK), Gastric inhibitory peptide (GIP)

• Mechanism of Hormone Action
• Hormones and their types
• Target cells have specific receptors

• Types of effects of hormones regulate metabolism and body functions
  1) Permissive effect
  2) Synergistic effect
  3) Antagonistic effect

• Gigantism
• Acromegaly
• Pituitary dwarfism
• Diabetes insipidus
• Graves' disease (Exophthalmic goiter)
• Cretinism
• Goitre
• Addison's disease
• Diabetes mellitus