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CYTOLOGY NOTES

1. Introduction

 Cytology = Study of cells (structure, function, composition).

 Coined by Robert Hooke (1665) → observed cork cells.
 Cell theory:
o All living beings are made up of cells (Schleiden & Schwann,
1839).
o Cell is the structural and functional unit of life.
o All cells arise from pre-existing cells (Virchow, 1855).
o Modern additions:
 Cell contains hereditary material.
 Energy flow occurs within cells.

2. Types of Cells

 Prokaryotic cells:
o No true nucleus (DNA free in nucleoid).
o No membrane-bound organelles.
o Eg: Bacteria, Cyanobacteria (Blue-green algae), Mycoplasma.
 Eukaryotic cells:
o True nucleus with nuclear envelope.
o Membrane-bound organelles.
o Eg: Plants, animals, fungi, protists.

3. Cell Organelles (Eukaryotic)

(a) Plasma Membrane

 Structure: Fluid Mosaic Model (Singer & Nicolson, 1972).

 Composition: Phospholipid bilayer + proteins + cholesterol.
 Functions: Selective permeability, cell signaling, transport (active,
passive).

(b) Nucleus

 Double-membrane bound.
 Contains DNA → genetic material.
 Components:
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o Nuclear envelope – pores for transport.

o Nucleolus – site of rRNA synthesis.
o Chromatin – euchromatin (active), heterochromatin (inactive).

(c) Mitochondria

 Powerhouse of cell – ATP generation.

 Double membrane; inner folded into cristae.
 Own DNA & ribosomes (70S).
 Semiautonomous; endosymbiotic origin theory.

(d) Endoplasmic Reticulum (ER)

 Rough ER (RER): studded with ribosomes → protein synthesis.

 Smooth ER (SER): lipid synthesis, detoxification.

(e) Golgi Apparatus

 Discovered by Camillo Golgi.

 Functions: Modification, packaging, and secretion of proteins & lipids;
lysosome formation.

(f) Lysosomes

 “Suicidal bags” of cell.

 Contain hydrolytic enzymes (digestive).
 Role in apoptosis, autophagy.

(g) Ribosomes

 Non-membranous.
 Protein synthesis site (“protein factory”).
 Types:
o 70S: Prokaryotes, mitochondria, chloroplasts.
o 80S: Eukaryotes.

(h) Chloroplast (Plant cells)

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 Double membrane.
 Site of photosynthesis.
 Contains chlorophyll (in thylakoids → grana).
 Own DNA & ribosomes.

(i) Vacuoles

 Membrane-bound sacs (tonoplast).

 Storage, waste disposal, osmotic balance.
 Large central vacuole in plant cells.

(j) Cytoskeleton

 Network of protein filaments:

o Microtubules.
o Microfilaments (actin).
o Intermediate filaments.
 Functions: Shape, movement, intracellular transport.

(k) Centrosome & Centrioles

 Animal cells only.

 Organize spindle fibers during cell division.

4. Cell Division

 Mitosis (Equational division):

o Produces two genetically identical daughter cells.
o Stages: Prophase, Metaphase, Anaphase, Telophase.
 Meiosis (Reductional division):
o Produces gametes/spores.
o Two successive divisions → 4 haploid daughter cells.
o Increases genetic variation (crossing over in Prophase I).

5. Cell Cycle

 Interphase: G1 (growth), S (DNA replication), G2 (preparation).

 M phase: mitosis + cytokinesis.
 Checkpoints regulate cycle; controlled by cyclins & CDKs.
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6. Differences between Plant & Animal Cells

Feature Plant Cell Animal Cell

Cell wall Present (cellulose) Absent
Plastids Present Absent
Vacuoles Large central Small, temporary
Centrosome Absent (except in lower plants) Present
Lysosomes Rare Common

7. Applied Aspects

 Cytopathology – study of cells for disease diagnosis.

 Stem cells – undifferentiated cells with regenerative capacity.
 Cancer – uncontrolled cell division due to mutations in proto-
oncogenes/tumor suppressor genes.

✅ Quick Recap for Exams:

 Cell → structural & functional unit.

 Prokaryotes lack nucleus & organelles.
 Eukaryotes: Organelles with membranes.
 Key organelles → nucleus (DNA), mitochondria (ATP), ribosome
(protein), chloroplast (photosynthesis).
 Cell cycle → G1, S, G2, M.
 Mitosis = 2 identical cells; Meiosis = 4 haploid, variation.

1. Animal Cell vs Plant Cell

A. Introduction

 Cell = structural and functional unit of life.

 Both animal and plant cells are eukaryotic, i.e., have nucleus and
membrane-bound organelles.
 Key differences arise due to function and lifestyle.

B. Structure & Components

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Component / Animal
Plant Cell Notes
Organelle Cell
Present (made of Provides rigidity &
Cell Wall Absent
cellulose) shape
Irregular / Due to cell wall in
Shape Fixed / Rectangular
Round plants
Plasma
Present Present Selective barrier
Membrane
Contains DNA,
Nucleus Present Present
controls cell
Jelly-like matrix,
Cytoplasm Present Present
organelles suspended
Photosynthesis;
Chloroplast Absent Present
contains chlorophyll
Stores water,
Small or
Vacuole Large central vacuole nutrients, maintains
absent
turgor
Lysosomes Present Rare / absent Digestion of waste
Absent (except some
Centrioles Present Cell division
lower plants)
Energy production
Mitochondria Present Present
(ATP)
Present (chloroplast,
Photosynthesis,
Plastids Absent chromoplast,
pigment storage
leucoplast)
Present in some plant Converts fats to carbs
Glyoxysomes Absent
cells in seeds

C. Key Features

 Plant cell: autotrophic, rigid wall, chloroplasts, large vacuole.

 Animal cell: heterotrophic, flexible, lysosomes, centrioles.
 Both contain ER, Golgi, ribosomes, mitochondria, peroxisomes.

D. Quick Comparison Table for Exams

Feature Animal Cell Plant Cell

Cell wall Absent Present
Shape Round / irregular Rectangular / fixed
Chloroplast Absent Present
Vacuole Small / many Large central vacuole
Lysosome Present Rare
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Feature Animal Cell Plant Cell

Centrioles Present Absent
Energy source Food intake (heterotroph) Photosynthesis (autotroph)

E. Important Points

 Both are eukaryotic, membrane-bound organelles present.

 Plant cell → autotrophic, has plastids.
 Animal cell → heterotrophic, has lysosomes & centrioles.
 Plant cell wall → cellulose; animal cell → flexible plasma membrane.
 Vacuole size → plant cell (large), animal cell (small).

PLANT TISSUES NOTES

1. Introduction

 Tissue = Group of similar cells performing a specific function.

 In plants, tissues are of two major types:
1. Meristematic tissues – actively dividing cells.
2. Permanent tissues – differentiated, mature cells.

2. Meristematic Tissues

👉 Characteristics: Thin cell wall, dense cytoplasm, large nucleus, no

vacuoles, actively dividing.

Types

1. Based on origin:
o Primary meristem – directly from embryonic cells (root tip,
shoot tip).
o Secondary meristem – formed later from permanent tissue
(cambium, cork cambium).
2. Based on position:
o Apical meristem: At tips of roots & shoots → increase in length
(primary growth).
o Intercalary meristem: At base of leaves or nodes (grasses) →
regrowth.
o Lateral meristem: Along sides of stem & root (cambium, cork
cambium) → increase in girth (secondary growth).
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3. Permanent Tissues

(A) Simple Permanent Tissue

Made of similar types of cells.

1. Parenchyma
o Living, thin-walled, loosely packed.
o Functions: storage, photosynthesis (chlorenchyma), buoyancy
(aerenchyma).
2. Collenchyma
o Living, elongated, cell wall thickened at corners (cellulose &
pectin).
o Provides flexibility & mechanical support (eg. petioles, stems).
3. Sclerenchyma
o Dead, thick lignified walls.
o Provides rigidity & strength.
o Types:
 Fibres – long, slender.
 Sclereids (stone cells) – irregular, found in nutshells,
pear grittiness.

(B) Complex Permanent Tissue

Made of different types of cells; function in transport.

1. Xylem (water conduction, upward movement)

o Components:
 Tracheids – elongated, lignified, dead.
 Vessels – tube-like, main water-conducting.
 Xylem fibres – support.
 Xylem parenchyma – storage, lateral conduction.
2. Phloem (food conduction, bidirectional)
o Components:
 Sieve tubes – transport food.
 Companion cells – control sieve tubes.
 Phloem parenchyma – storage.
 Phloem fibres – support.

4. Special (Secretory) Tissues

 Laticiferous tissue → secretes latex (rubber, poppy).

 Glandular tissue → secretes resins, oils, nectar.
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5. Differences at a Glance

Tissue Type Key Features Function

Meristematic Small, thin wall, actively dividing Growth
Storage,
Parenchyma Living, thin wall
photosynthesis
Collenchyma Living, thickened corners Flexibility, support
Sclerenchyma Dead, lignified Strength, rigidity
Tracheids + vessels (dead),
Xylem Water transport
conduction
Phloem Sieve tubes + companion cells (living) Food transport

✅ Quick Recap for Exams:

 Meristematic tissues → growth (apical = length, lateral = girth).

 Permanent tissues → simple (parenchyma, collenchyma,
sclerenchyma) & complex (xylem, phloem).
 Xylem = water, Phloem = food.

ANIMAL TISSUES NOTES

1. Introduction

 Tissue = Group of similar cells performing a specific function.

 In animals, tissues are classified into 4 main types:
1. Epithelial Tissue – covering/protective.
2. Connective Tissue – support & binding.
3. Muscular Tissue – movement.
4. Nervous Tissue – control & coordination.

2. Epithelial Tissue

👉 Covers body surface, lines organs, forms glands.

👉 Characteristics: Closely packed, little intercellular space, rests on
basement membrane.

Types:
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1. Simple Epithelium (single layer):

o Squamous → flat, thin (lungs alveoli, blood vessels).
o Cuboidal → cube-shaped (glands, kidney tubules).
o Columnar → tall (intestine, stomach).
o Ciliated → with cilia (respiratory tract, Fallopian tubes).
2. Compound Epithelium (many layers):
o Stratified squamous → skin, esophagus.
o Transitional epithelium → urinary bladder (stretchable).
3. Glandular Epithelium → secretion (sweat, salivary glands).

3. Connective Tissue

👉 Binds, supports, protects body & organs.

👉 Has cells + matrix (fibres + ground substance).

Types:

1. Connective Tissue Proper

o Loose:
 Areolar – between skin & muscles; packing material.
 Adipose – fat storage, insulation.
o Dense:
 Tendons – connect muscle to bone.
 Ligaments – connect bone to bone (elastic).
2. Skeletal Connective Tissue
o Cartilage – flexible, chondrocytes in lacunae (nose, ear, joints).
o Bone – rigid, osteocytes in lacunae, Ca salts → support,
protection, muscle attachment.
3. Fluid Connective Tissue
o Blood → plasma + RBCs + WBCs + platelets; transport O₂,
nutrients, waste.
o Lymph → colorless, helps in immunity & transport of fat.

4. Muscular Tissue

👉 Specialized for movement (contractile).

👉 Made of muscle fibres with contractile proteins actin & myosin.

Types:

1. Striated (Skeletal/Voluntary Muscle)

o Long, cylindrical, multinucleated, striations present.
o Voluntary control (attached to bones, locomotion).
2. Unstriated (Smooth/Involuntary Muscle)
o Spindle-shaped, single nucleus, no striations.
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Involuntary (stomach, intestine, blood vessels).

o
3. Cardiac Muscle
o Striated, branched, uninucleated, intercalated discs.
o Involuntary, rhythmic contraction (heart).

5. Nervous Tissue

👉 Specialized for conduction of nerve impulses.

👉 Basic unit = Neuron.

Structure of Neuron:

 Cell body (cyton) – nucleus, Nissl bodies.

 Dendrites – receive impulses.
 Axon – transmits impulses away.
 Myelin sheath – insulation (Schwann cells).

👉 Functions: Coordination, reflexes, control of body functions.

6. Quick Differences Table

Tissue Subtypes Key Function

Epithelial Simple, compound, glandular Protection, secretion, absorption
Connective Proper, skeletal, fluid Support, transport, binding
Muscular Skeletal, smooth, cardiac Movement, locomotion
Nervous Neurons, neuroglia Control & coordination

✅ Quick Recap for Exams:

 Epithelial = covering (skin, glands).

 Connective = most abundant (bone, cartilage, blood, lymph).
 Muscle = movement (skeletal voluntary, smooth involuntary, cardiac
involuntary rhythmic).
 Nervous = neuron-based, impulses.

BLOOD AND ITS COMPOSITION

👉 Blood = Specialized fluid connective tissue.
👉 Average adult human = ~ 5–6 liters of blood.
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👉 Functions: Transport (O₂, CO₂, nutrients, hormones), defense (WBCs,

antibodies), regulation (pH, temp), clotting.

Composition of Blood

Blood has two major components:

(A) Plasma (55%)

 Pale yellow fluid (~90–92% water).

 Solutes: proteins (albumin, globulin, fibrinogen), glucose, amino acids,
lipids, salts, hormones, urea, CO₂.
 Functions: Transport medium, maintains osmotic balance, blood
clotting (fibrinogen).

(B) Formed Elements (45%)

1. Red Blood Cells (RBCs / Erythrocytes)

o Most abundant (5–5.5 million/mm³).
o Biconcave, enucleated (in mammals).
o Contains hemoglobin → transports O₂ & CO₂.
o Lifespan ~120 days; destroyed in spleen (“graveyard of RBCs”).
2. White Blood Cells (WBCs / Leucocytes)
o Count: 6,000–8,000/mm³.
o Defense & immunity.
o Types:
 Granulocytes:
 Neutrophils (phagocytosis, most abundant).
 Eosinophils (allergy, parasites).
 Basophils (histamine release, allergy).
 Agranulocytes:
 Lymphocytes (B & T cells → immunity, antibodies).
 Monocytes (differentiate into macrophages,
phagocytosis).
3. Platelets (Thrombocytes)
o Small, non-nucleated fragments.
o Count: 2.5–4.5 lakh/mm³.
o Role: Blood clotting (release thromboplastin).

NERVE CELLS (NEURONS)

👉 Neuron = Structural & functional unit of nervous system.
👉 Function: Conducts nerve impulses (electrochemical signals).
👉 Specialized for control, coordination, reflexes.

Structure of Neuron
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1. Cell Body (Cyton/Soma)

o Contains nucleus, cytoplasm, Nissl bodies (ribosome-rich).
o Controls metabolism & growth.
2. Dendrites
o Short, branched projections.
o Receive impulses & transmit toward cell body.
3. Axon
o Long, cylindrical process.
o Covered by myelin sheath (insulation, faster conduction).
o Ends in axon terminals → synaptic knobs.
o Transmits impulse away from cell body.
4. Synapse
o Junction between axon terminal of one neuron & dendrite of
another.
o Neurotransmitters (e.g., acetylcholine, dopamine) transmit
signal.

Types of Neurons (based on function):

 Sensory neurons – carry impulses from receptors → CNS.

 Motor neurons – carry impulses from CNS → effectors (muscles,
glands).
 Interneurons – link between sensory & motor within CNS.

Key Differences: Blood vs Neuron

Feature Blood Neuron

Type Connective tissue Nervous tissue
Conduct impulses,
Function Transport, defense, clotting
coordination
Formed elements (RBC, WBC, Neuron (cell body, dendrites,
Unit
platelets) axon)
Neuron = lifetime (do not
Lifespan RBCs ~120 days
divide)

✅ Quick Exam Recap:

 Blood = Plasma (55%) + Formed elements (45%).

 RBCs → O₂ transport, WBCs → immunity, Platelets → clotting.
 Neuron = Cyton + Dendrites + Axon.
 Synapse → neurotransmitter-based impulse transmission.

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FIVE KINGDOM CLASSIFICATION (Whittaker,

1969)

1. Basis of Classification

Whittaker classified organisms into five kingdoms based on:

 Cell type → Prokaryotic / Eukaryotic

 Cell organization → Unicellular / Multicellular
 Mode of nutrition → Autotrophic / Heterotrophic
 Reproduction → Asexual / Sexual
 Phylogenetic relationships

2. The Five Kingdoms

(A) Kingdom Monera

 Cell type: Prokaryotic.

 Organization: Unicellular.
 Nucleus: Absent (nucleoid instead).
 Cell wall: Present (peptidoglycan in bacteria).
 Nutrition: Autotrophic (chemo/photosynthetic) or Heterotrophic
(saprophytic, parasitic).
 Reproduction: Asexual (binary fission, conjugation).
 Examples: Bacteria, Cyanobacteria (blue-green algae), Mycoplasma,
Archaebacteria.

(B) Kingdom Protista

 Cell type: Eukaryotic.

 Organization: Mostly unicellular (some colonial).
 Nucleus: True nucleus, membrane-bound organelles present.
 Nutrition: Autotrophic (algae), heterotrophic (protozoa), mixotrophic
(Euglena).
 Reproduction: Asexual (binary fission), sexual (syngamy).
 Examples: Amoeba, Paramecium, Euglena, Diatoms, Dinoflagellates.

(C) Kingdom Fungi

 Cell type: Eukaryotic.

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 Organization: Mostly multicellular (except yeast – unicellular).

 Cell wall: Present (chitin).
 Nutrition: Heterotrophic – saprophytic, parasitic, symbiotic (lichen,
mycorrhiza).
 Body structure: Hyphae → mycelium.
 Reproduction: Asexual (spores, budding), sexual (fusion of gametes).
 Examples: Rhizopus (bread mould), Agaricus (mushroom),
Saccharomyces (yeast), Penicillium.

(D) Kingdom Plantae

 Cell type: Eukaryotic.

 Organization: Multicellular.
 Cell wall: Present (cellulose).
 Nutrition: Autotrophic (photosynthesis).
 Reproduction: Both asexual (spores, vegetative) and sexual.
 Examples: Algae, Bryophytes (moss), Pteridophytes (ferns),
Gymnosperms (pines), Angiosperms (flowering plants).

(E) Kingdom Animalia

 Cell type: Eukaryotic.

 Organization: Multicellular.
 Cell wall: Absent.
 Nutrition: Heterotrophic (ingestive).
 Reproduction: Mainly sexual.
 Examples: Porifera (sponges) → Chordata (humans).

3. Comparison Table

Feature Monera Protista Fungi Plantae Animalia

Cell type Prokaryotic Eukaryotic Eukaryotic Eukaryotic Eukaryotic
Nucleus Absent Present Present Present Present
Multicellula
Body Multicellul Multicellula
Unicellular Unicellular r (except
form ar r
yeast)
Peptidoglyca Present in some
Cell wall Chitin Cellulose Absent
n (cellulose/silica)
Mode of Heterotroph
Auto/Hetero/Mi Autotrophi Heterotroph
nutritio Auto/Hetero ic
xo c ic (ingestive)
n (absorptive)
Example Bacteria, Amoeba, Yeast, Ferns, Humans,
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Feature Monera Protista Fungi Plantae Animalia

s Cyanobacter Euglena Mushroom Flowering Lions
ia plants

4. Advantages of Whittaker’s Classification

 Clear separation of prokaryotes (Monera) from eukaryotes.

 Distinguishes unicellular eukaryotes (Protista).
 Fungi separated from plants due to heterotrophic mode.
 Shows evolutionary relationships.

5. Limitations

 Archaebacteria & Eubacteria kept together in Monera, though very

different.
 Viruses not included (acellular).
 Protista is too diverse (algae, protozoa, slime moulds grouped
together).

✅ Quick Recap for Exams:

 Monera = Prokaryotes.
 Protista = Unicellular eukaryotes.
 Fungi = Multicellular, heterotrophic (chitin wall).
 Plantae = Autotrophic (cellulose wall).
 Animalia = Multicellular, heterotrophic (no cell wall).

KINGDOM PLANTAE (Plants)

1. General Characteristics

 Cell type: Eukaryotic, multicellular.

 Cell wall: Present, made of cellulose.
 Nutrition: Mostly autotrophic (photosynthetic → chlorophyll a, b).
 Storage food: Starch.
 Reproduction: Both asexual (spores, vegetative) and sexual.
 Life cycle: Shows alternation of generations (haploid gametophyte
↔ diploid sporophyte).
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2. Major Groups of Plantae

(A) Algae

 Simple, autotrophic, mostly aquatic plants.

 Body: Thallus (no roots, stems, leaves).
 Reproduction: Vegetative (fragmentation), asexual (spores), sexual.
 Groups:
1. Chlorophyceae (Green algae) – chlorophyll a & b; e.g.,
Chlamydomonas, Spirogyra, Ulva.
2. Phaeophyceae (Brown algae) – chlorophyll a & c + fucoxanthin;
cell wall with algin; e.g., Laminaria, Fucus, Sargassum.
3. Rhodophyceae (Red algae) – chlorophyll a & d + phycoerythrin;
mostly marine; e.g., Polysiphonia, Gelidium.

(B) Bryophytes (Amphibians of plant kingdom)

 Small plants, grow in moist, shady places.

 Plant body: Gametophyte dominant, sporophyte dependent.
 True roots absent → rhizoids present.
 Water needed for fertilization (motile sperm).
 E.g., Mosses (Funaria), Liverworts (Riccia, Marchantia).

(C) Pteridophytes (First vascular plants)

 First true land plants with vascular tissue (xylem & phloem).
 No seeds → reproduce by spores.
 Dominant sporophyte with independent gametophyte.
 E.g., Ferns (Pteris, Dryopteris), Horsetails (Equisetum).

(D) Gymnosperms (Naked seed plants)

 Vascular plants with seeds not enclosed in fruit.

 Usually perennial, woody, with needle-like leaves.
 Mostly wind-pollinated.
 E.g., Cycas, Pinus, Ginkgo, Ephedra.

(E) Angiosperms (Flowering plants)

 Most advanced group of plants.

 Seeds enclosed within fruit.
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 Have flowers, fruits, double fertilization (unique feature).

 Divided into:
o Monocots: one cotyledon, parallel venation, fibrous roots (rice,
wheat, maize).
o Dicots: two cotyledons, reticulate venation, tap roots (pea,
mango, sunflower).

3. Alternation of Generations

 Gametophyte (n) produces gametes → fuse to form zygote.

 Sporophyte (2n) develops from zygote, produces spores by meiosis.
 Alternation varies:
o Algae – haplontic/diplontic/isomorphic.
o Bryophytes – gametophyte dominant.
o Pteridophytes, Gymnosperms, Angiosperms – sporophyte
dominant.

4. Economic Importance of Plantae

 Food: Cereals, pulses, fruits, vegetables.

 Medicine: Cinchona (quinine), Papaver (morphine), Aloe.
 Timber & Fibres: Teak, jute, cotton.
 Industrial: Paper (bamboo), oils, rubber, resins.
 Ecological: O₂ production, CO₂ absorption, soil fertility, habitat.

5. Quick Classification Recap

Group Vascular tissue Seeds Flowers Examples

Algae Absent Absent Absent Spirogyra, Ulva
Bryophytes Absent Absent Absent Moss, Riccia
Pteridophytes Present Absent Absent Fern, Equisetum
Gymnosperms Present Present (naked) Absent Cycas, Pinus
Angiosperms Present Present (enclosed) Present Mango, Rice

✅ Quick Exam Recap:

 Algae = simple, aquatic, photosynthetic.

 Bryophytes = amphibians of plant kingdom.
 Pteridophytes = first vascular plants.
 Gymnosperms = naked seed plants.
 Angiosperms = flowering plants, most advanced.
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KINGDOM ANIMALIA (Animals)

1. General Characteristics

 Cell type: Eukaryotic, multicellular.

 Cell wall: Absent.
 Nutrition: Heterotrophic, ingestive (holozoic).
 Locomotion: Present (muscles + nerve coordination).
 Storage food: Glycogen.
 Reproduction: Mainly sexual (gametic fusion).
 Development: Embryonic stages present (zygote → embryo → adult).

2. Basis of Classification

Animals are classified based on:

 Body symmetry: Asymmetrical / Radial / Bilateral.

 Germ layers: Diploblastic (2 layers) / Triploblastic (3 layers).
 Coelom (body cavity): Acoelomate / Pseudocoelomate / Coelomate.
 Segmentation: Absent / Present.
 Notochord: Absent (Non-chordates) / Present (Chordates).

3. Major Groups of Animalia

(A) Non-Chordates (no notochord)

1. Porifera (Sponges)
o Asymmetrical, cellular level of organization.
o Pores (ostia), water canal system.
o Skeleton of spicules/spongin.
o Eg: Sycon, Spongilla, Euplectella.
2. Coelenterata (Cnidaria)
o Radial symmetry, diploblastic.
o Stinging cells (cnidoblasts).
o Polyp & medusa forms.
o Eg: Hydra, Jellyfish, Sea anemone.
3. Platyhelminthes (Flatworms)
o Bilateral, triploblastic, acoelomate.
o Many parasitic (Tapeworm, Liver fluke).
o Eg: Planaria.
4. Nematoda (Roundworms)
o Bilateral, triploblastic, pseudocoelomate.
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Parasitic forms → Ascaris, Wuchereria.

o
5. Annelida (Segmented worms)
o True coelom, metameric segmentation.
o Closed circulatory system.
o Eg: Earthworm, Leech, Nereis.
6. Arthropoda (largest phylum)
o Jointed appendages, exoskeleton (chitin).
o Open circulatory system.
o Eg: Insects (Cockroach), Crustaceans (Crab), Arachnids (Spider).
7. Mollusca
o Soft body, calcareous shell.
o Muscular foot, mantle.
o Open circulatory system.
o Eg: Snail, Octopus, Pila.
8. Echinodermata
o Marine, spiny-skinned.
o Radial symmetry (adult), bilateral (larva).
o Water vascular system.
o Eg: Starfish, Sea urchin.

(B) Chordates (with notochord, dorsal nerve cord, pharyngeal gills, post-
anal tail)

 Subphylum → Vertebrata (true backbone).

Classes of Vertebrates

1. Pisces (Fishes)
o Aquatic, gills for respiration.
o Scales, fins, cold-blooded.
o Eg: Rohu, Shark.
2. Amphibia
o “Dual life” → water & land.
o Gills (larva), lungs (adult).
o Eg: Frog, Salamander.
3. Reptilia
o Dry skin, scales, cold-blooded.
o Lay cleidoic (shelled) eggs.
o Eg: Snake, Crocodile, Turtle.
4. Aves (Birds)
o Forelimbs modified into wings.
o Feathers, beak, pneumatic bones.
o Warm-blooded, oviparous.
o Eg: Pigeon, Crow, Ostrich.
5. Mammalia
o Body covered with hair, mammary glands.
o Warm-blooded, mostly viviparous.
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o Eg: Human, Dog, Whale, Bat.

4. Comparison: Non-Chordates vs Chordates

Feature Non-Chordates Chordates

Notochord Absent Present

Nerve cord Ventral, solid Dorsal, hollow

Circulatory system Mostly open Closed

Pharyngeal gills Absent Present at some stage

Example Arthropods, Molluscs Fishes, Birds, Mammals

5. Quick Recap for Exams

 Porifera → pores, canal system.

 Cnidaria → stinging cells, polyp/medusa.
 Platyhelminthes → flatworms, acoelomate.
 Nematoda → roundworms, pseudocoelom.
 Annelida → segmentation, coelom.
 Arthropoda → largest phylum, jointed legs.
 Mollusca → soft body, shell.
 Echinodermata → marine, water vascular system.
 Chordates → notochord, dorsal nerve cord, post-anal tail.

Plant Physiology

1. Photosynthesis

👉 Process by which green plants synthesize food (glucose) using CO₂,

H₂O, and sunlight in the presence of chlorophyll.

Equation:

6CO2+12H2O→Light,ChlorophyllC6H12O6+6O2+6H2O6CO₂ + 12H₂O
\xrightarrow{Light, Chlorophyll} C₆H₁₂O₆ + 6O₂ + 6H₂O6CO2+12H2
OLight,ChlorophyllC6H12O6+6O2+6H2O

 Site: Chloroplast (mesophyll cells of leaves).

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 Pigments:
o Chlorophyll a (main, blue-green)
o Chlorophyll b, carotenoids, xanthophylls (accessory)

Stages:

1. Light Reaction (in thylakoid membrane)

o Photolysis of water → O₂ released.
o ATP & NADPH formed (energy currency).
2. Dark Reaction (Calvin Cycle in stroma)
o CO₂ fixation → Glucose formed.

✅ Factors affecting: Light, CO₂ concentration, Temperature, Water.

2. Respiration in Plants

👉 Breakdown of glucose to release ATP (energy).

Types:

1. Aerobic respiration (with O₂, in mitochondria)

o Glucose → CO₂ + H₂O + 36 ATP
2. Anaerobic respiration (without O₂, in cytoplasm)
o Glucose → Ethanol + CO₂ + 2 ATP (e.g., yeast)
3. Fermentation → similar to anaerobic, less energy.

3. Transpiration

👉 Loss of water as vapor through stomata.

Types:

 Stomatal (major), Cuticular, Lenticular.

Functions:

 Helps in water movement (transpiration pull).

 Cooling effect.

Factors affecting: Light, Temperature, Humidity, Wind, Soil water.

4. Transport in Plants
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 Xylem → Conducts water & minerals (unidirectional).

 Phloem → Conducts food (bidirectional).

Mechanisms:

 Ascent of sap: Cohesion-tension theory (transpiration pull).

 Translocation of food: Pressure-flow hypothesis.

5. Plant Growth & Hormones (Phytohormones)

Major Plant Hormones:

1. Auxins – cell elongation, phototropism, apical dominance. (Eg: IAA)

2. Gibberellins (GA) – stem elongation, seed germination, bolting.
3. Cytokinins – cell division, delay senescence, lateral growth.
4. Abscisic Acid (ABA) – stress hormone, stomatal closure, dormancy.
5. Ethylene – fruit ripening, leaf abscission, flowering.

6. Nitrogen Metabolism

 Plants absorb nitrogen as Nitrates (NO₃⁻), Nitrites (NO₂⁻), Ammonium

(NH₄⁺).
 Nitrogen fixation:
o Symbiotic (Rhizobium in legumes).
o Free-living (Azotobacter, Clostridium, Cyanobacteria).
 Enzyme Nitrogenase reduces N₂ → NH₃.

7. Tropic Movements (Responses to Stimuli)

 Phototropism → towards light (shoot).

 Geotropism → towards gravity (root).
 Hydrotropism → towards water.
 Thigmotropism → response to touch (tendrils).

8. Mineral Nutrition in Plants

 Macronutrients → N, P, K, Ca, Mg, S.

 Micronutrients → Fe, Mn, Zn, Cu, Mo, B, Cl.

Deficiency Symptoms:
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 N → stunted growth, yellow leaves.

 P → poor root growth.
 K → weak stem, scorching of leaf tips.
 Fe → chlorosis (yellowing between veins).

✅ Quick Exam Points:

 Photosynthesis site → Chloroplast.

 Respiration site → Mitochondria.
 Transpiration → through stomata.
 Water transport → Xylem.
 Food transport → Phloem.
 Plant growth regulators → 5 hormones.
 Nitrogen fixation bacteria → Rhizobium, Azotobacter.

Human Digestive System

1. Introduction

 The human digestive system is responsible for breaking down food →

absorbing nutrients → removing undigested waste.
 Main processes: Ingestion → Digestion → Absorption →
Assimilation → Egestion.

2. Parts of Digestive System

A. Alimentary Canal

1. Mouth (Buccal cavity)

o Teeth → mechanical digestion (32 permanent teeth).
o Tongue → mixing, taste, swallowing.
o Salivary glands (3 pairs: Parotid, Sublingual, Submandibular) →
secrete saliva containing ptyalin (salivary amylase) → starch
→ maltose.
2. Pharynx
o Common passage for food & air.
o Epiglottis prevents food entering windpipe.
3. Oesophagus (Food pipe)
o Peristalsis pushes food into stomach.
4. Stomach
o J-shaped, muscular bag.
o Gastric glands secrete:
 HCl → kills bacteria, activates pepsinogen.
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 Pepsin → proteins → peptones.

 Rennin (in infants) → milk digestion.
 Mucus → protects lining.
5. Small Intestine (Duodenum + Jejunum + Ileum)
o Main site of digestion & absorption.
o Duodenum: receives bile (from liver) & pancreatic juice (from
pancreas).
 Bile (no enzyme, alkaline) → emulsifies fats.
 Pancreatic enzymes:
 Trypsin (proteins → peptides).
 Lipase (fats → fatty acids + glycerol).
 Amylase (starch → maltose).
o Intestinal juice (succus entericus) → completes digestion.
o Villi & microvilli → increase absorption surface.
6. Large Intestine
o Absorbs water, minerals, vitamins.
o Houses bacteria (e.g., E. coli → vitamin K & B-complex).
o Rectum → stores feces.
o Anus → egestion.

B. Digestive Glands

1. Salivary glands → saliva, amylase.

2. Liver → largest gland (1.5 kg), secretes bile (stored in gall bladder).
3. Pancreas → mixed gland (exocrine + endocrine). Produces insulin,
glucagon, and digestive enzymes.
4. Intestinal glands → secrete intestinal juice.

3. Digestion of Food (Stepwise)

Nutrient Enzyme End Product

Carbohydrates (starch) Amylase (saliva, pancreas) Maltose → Glucose
Proteins Pepsin, Trypsin, Peptidase Amino acids
Fats Bile + Lipase Fatty acids + Glycerol

4. Absorption of Nutrients

 Glucose & amino acids → blood capillaries (via villi).

 Fatty acids & glycerol → lymph (as chylomicrons).

5. Disorders of Digestive System

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 Constipation → improper bowel movement.

 Diarrhoea → watery stools (loss of water & salts).
 Jaundice → excess bile pigment (bilirubin).
 Ulcer → sores in stomach lining (caused by H. pylori).
 Gallstones → crystallization of cholesterol in gall bladder.

6. Quick Exam Points

 Longest part → Small intestine (6 m).

 Shortest part → Oesophagus (25 cm).
 Largest gland → Liver.
 Bile has no enzyme but helps in fat digestion.
 Glucose → main energy source.
 Villi → absorption units.
 Digestion starts in mouth and completes in small intestine.

Human Eye

1. Introduction

 The human eye is a sense organ of vision.

 Works like a camera:
o Cornea + Lens → focus light.
o Retina → screen with photoreceptors.
o Brain (optic nerve) → interprets image.

2. Structure of Human Eye

Approx. diameter: 2.5 cm.

A. Outer Layers

1. Sclera → white, tough outer covering (protection).

2. Cornea → transparent front part; refracts (bends) light entering eye.

B. Middle Layer (Uveal tract)

1. Choroid → vascular, provides nourishment.

2. Ciliary body → controls shape of lens, secretes aqueous humor.
3. Iris → colored part; controls size of pupil (regulates light).

C. Inner Layer
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1. Retina → contains photoreceptor cells:

o Rods → black & white vision, dim light.
o Cones → color vision, bright light.
2. Macula lutea (yellow spot) → maximum cones → sharp vision.
3. Blind spot → no rods/cones; optic nerve exits here.

3. Lens & Humors

 Lens → biconvex, transparent, focuses light on retina.

 Aqueous humor → watery fluid between cornea & lens.
 Vitreous humor → jelly-like, maintains eyeball shape.

4. Working of Eye

 Refraction of light → Cornea & lens bend light.

 Accommodation → Lens changes shape for near/far objects.
 Image formed → Real, inverted, smaller image on retina.
 Brain (via optic nerve) inverts it to erect.

5. Common Eye Defects

1. Myopia (Nearsightedness)
o Image before retina (cannot see far).
o Corrected by concave lens.
2. Hypermetropia (Farsightedness)
o Image behind retina (cannot see near).
o Corrected by convex lens.
3. Presbyopia
o Old-age defect (lens loses flexibility).
o Corrected by bifocal lenses.
4. Astigmatism
o Uneven curvature of cornea/lens.
o Corrected by cylindrical lens.
5. Cataract
o Lens becomes opaque → blindness.
o Treated by surgery + artificial lens.

6. Quick Facts for Exams

 Eye lens → biconvex.

 Retina → screen of eye.
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 Rods contain pigment Rhodopsin (visual purple).

 Cones contain pigment Iodopsin.
 Vitamin A deficiency → Night blindness.
 In dim light → rods active; in bright light → cones active.
 Normal vision = 25 cm (near point) to infinity (far point).

Human Teeth

1. Introduction

 Teeth are hard structures in the mouth → help in cutting, tearing,

chewing (mastication) of food.
 Also important for speech & appearance.
 Made of calcium salts (Ca phosphate, Ca carbonate).
 Hardest substance in body = Enamel.

2. Types of Dentition in Humans

1. Thecodont → teeth embedded in sockets of jawbones.

2. Diphyodont → two sets of teeth in lifetime:
o Milk (deciduous) teeth → 20 (appear ~6 months, complete by 2
yrs).
o Permanent teeth → 32 (appear 6–25 yrs).
3. Heterodont → different types of teeth.

3. Types of Teeth (Permanent Dentition Formula)

Dental formula (adult human):

2 1 2 32 1 2 3×2=32\frac{2\ 1\ 2\ 3}{2\ 1\ 2\ 3} \times 2 =

322 1 2 32 1 2 3×2=32

 Incisors (I) → 2 per quadrant → cutting.

 Canines (C) → 1 per quadrant → tearing.
 Premolars (PM) → 2 per quadrant → grinding.
 Molars (M) → 3 per quadrant → grinding & crushing.
(In children → 2 1 2 02 1 2 0×2=20\frac{2\ 1\ 2\ 0}{2\ 1\ 2\ 0}
\times 2 = 202 1 2 02 1 2 0×2=20).

4. Structure of a Tooth
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1. Crown → visible part, covered by enamel (hardest).

2. Dentin → beneath enamel, bonelike tissue.
3. Pulp cavity → contains nerves, blood vessels.
4. Root → fixed in jaw bone.
5. Cementum → covers root, anchors tooth.

5. Tooth Disorders / Diseases

 Dental caries (tooth decay) → caused by bacteria (Streptococcus

mutans) due to sugar fermentation → acids destroy enamel.
 Gingivitis → gum inflammation.
 Periodontitis → severe gum disease, loosens teeth.
 Tooth sensitivity → exposed dentin.

6. Quick Exam Points

 Total teeth in adult → 32.

 Enamel → hardest substance, made of calcium phosphate.
 First milk teeth → appear ~6 months.
 Wisdom teeth → 3rd molars, appear at 17–25 yrs.
 Dental formula (adult) → 2 1 2 3 / 2 1 2 3.
 Vitamin C deficiency → scurvy → bleeding gums.

Human Respiration

1. Introduction

 Respiration = biological process of releasing energy from food

(glucose).
 Types:
o External respiration → breathing (exchange of gases).
o Internal respiration (cellular) → breakdown of glucose inside
cells to release ATP.

2. Human Respiratory System

Organs Involved

1. Nostrils → air entry.

2. Nasal cavity → filters, warms, moistens air.
3. Pharynx → common passage for food & air.
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4. Larynx (voice box) → sound production.

5. Trachea (windpipe) → C-shaped cartilage rings prevent collapse.
6. Bronchi → 2 branches → lungs.
7. Lungs → spongy organs in thoracic cavity.
o Right lung → 3 lobes, Left lung → 2 lobes.
8. Bronchioles → Alveoli
o Alveoli = tiny air sacs = main site of gas exchange.

3. Mechanism of Breathing

 Inspiration (inhalation)
o Diaphragm contracts (flattens), ribs move up & out → chest
cavity enlarges → air enters lungs.
 Expiration (exhalation)
o Diaphragm relaxes (dome-shaped), ribs move down & in →
chest cavity shrinks → air pushed out.

Normal breathing rate: 12–16 times/min (adult).

4. Exchange of Gases

1. In alveoli:
o O₂ diffuses into blood (capillaries).
o CO₂ diffuses out of blood into alveoli.
2. In tissues:
o O₂ diffuses into cells.
o CO₂ diffuses into blood.

5. Cellular Respiration

👉 Happens inside mitochondria.

 Aerobic respiration (with O₂):

C6H12O6+6O2→6CO2+6H2O+36ATPC₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O +

36 ATPC6H12O6+6O2→6CO2+6H2O+36ATP

 Anaerobic respiration (without O₂):

o In humans (muscle fatigue): Glucose → Lactic acid + 2 ATP.
o In yeast: Glucose → Ethanol + CO₂ + 2 ATP.
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6. Transport of Gases

 Oxygen:
o 98% carried as oxyhaemoglobin in RBCs.
o 2% dissolved in plasma.
 Carbon dioxide:
o 70% as bicarbonates.
o 23% as carbaminohaemoglobin.
o 7% dissolved in plasma.

7. Control of Breathing

 Controlled by medulla oblongata (respiratory center in brain).

 Sensitive to CO₂ concentration in blood.

8. Respiratory Volumes

 Tidal Volume (TV): air in normal breath (~500 mL).

 Vital Capacity (VC): max air inhaled & exhaled (~4800 mL).
 Residual Volume (RV): air left in lungs (~1200 mL).
 Total Lung Capacity (TLC): ~6000 mL.

9. Respiratory Disorders

 Asthma → difficulty in breathing (bronchi inflammation).

 Bronchitis → inflammation of bronchi.
 Emphysema → damage to alveoli (due to smoking).
 Pneumonia → lung infection.
 Tuberculosis (TB) → caused by Mycobacterium tuberculosis.

10. Quick Exam Points

 Site of respiration → mitochondria.

 Main site of gas exchange → alveoli.
 Oxygen carried by → Haemoglobin.
 Breathing control → Medulla oblongata.
 ATP produced in aerobic → 36, anaerobic → 2.
 Smoking damages alveoli → emphysema.
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Human Excretory System

A. Introduction

 Excretion = process of removal of nitrogenous wastes (mainly urea),

salts, and excess water.
 Main organ → Kidney.

B. Structure of Human Excretory System

1. Kidneys (2, bean-shaped, ~150 g each)

o Functional unit = Nephron.
o Filters blood & forms urine.
2. Ureters (2 tubes) → carry urine from kidneys to urinary bladder.
3. Urinary bladder → stores urine.
4. Urethra → releases urine outside.

C. Structure of Nephron

 Glomerulus → tuft of capillaries, filters blood.

 Bowman’s capsule → cup-like structure around glomerulus.
 Proximal convoluted tubule (PCT) → reabsorbs nutrients, water,
ions.
 Loop of Henle → water & salt reabsorption.
 Distal convoluted tubule (DCT) → selective secretion & absorption.
 Collecting duct → collects urine.

D. Process of Urine Formation

1. Ultrafiltration → in Bowman’s capsule (blood plasma filtered).

2. Reabsorption → in PCT, loop of Henle, DCT (useful substances
reabsorbed).
3. Secretion → waste (H⁺, K⁺, urea) secreted into tubule.

👉 Final urine = urea, salts, water.

E. Excretory Disorders

 Uremia → high urea in blood.

 Kidney stones → crystallization of salts.
 Gout → uric acid accumulation in joints.
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 Dialysis → artificial filtration of blood.

F. Quick Exam Points

 Functional unit = Nephron.

 Waste excreted in humans = Urea (ureotelic).
 Hormone regulating urine formation = ADH (Antidiuretic Hormone).

Human Circulatory System

A. Introduction

 Circulation = transport of O₂, CO₂, nutrients, hormones, waste.

 System: Heart + Blood vessels + Blood.

B. Heart

 Muscular, cone-shaped organ (~300 g).

 Located in thoracic cavity, between lungs.
 Covered by pericardium.

Chambers (4)

1. Right atrium → receives deoxygenated blood from body (via vena

cava).
2. Right ventricle → pumps it to lungs (via pulmonary artery).
3. Left atrium → receives oxygenated blood from lungs (via pulmonary
veins).
4. Left ventricle → pumps it to body (via aorta).

👉 Valves (tricuspid, bicuspid/mitral, semilunar) prevent backflow.

C. Types of Circulation

1. Systemic circulation → body ↔ heart.

2. Pulmonary circulation → lungs ↔ heart.
3. Double circulation → blood passes through heart twice in one cycle
(oxygenated & deoxygenated separate).
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D. Blood Vessels

 Arteries → carry blood away from heart (usually oxygenated;

exception: pulmonary artery).
 Veins → carry blood towards heart (usually deoxygenated; exception:
pulmonary vein).
 Capillaries → thin-walled, exchange of gases/nutrients.

E. Blood Components

1. Plasma (55%) → water, proteins, salts, hormones.

2. RBCs (Erythrocytes) → contain haemoglobin, carry O₂.
3. WBCs (Leucocytes) → defense.
4. Platelets (Thrombocytes) → blood clotting.

F. Blood Groups

 ABO system (Landsteiner):

o A, B, AB, O.
o O → universal donor, AB → universal recipient.
 Rh factor → important in blood transfusion (Rh incompatibility
causes erythroblastosis fetalis).

G. Circulatory Disorders

 Hypertension → high BP.

 Arteriosclerosis → hardening of arteries.
 Heart attack (Myocardial infarction) → blockage of coronary artery.
 Stroke → brain blood supply blocked.
 Anaemia → low Hb.

H. Quick Exam Points

 Heartbeat normal rate → 72/min.

 Pacemaker of heart → SA node.
 Average BP → 120/80 mmHg.
 Pulmonary artery → only artery with deoxygenated blood.
 Pulmonary vein → only vein with oxygenated blood.
 Universal donor = O⁻, Universal recipient = AB⁺.
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Reproduction in Plants

A. Types of Reproduction

(i) Asexual Reproduction

 Single parent involved.

 Offspring are genetically identical (clones).
 No gametes, no fertilization.

Methods:

1. Vegetative Propagation → new plant grows from root, stem, leaf.

o Natural → Potato (tuber), Onion (bulb), Ginger (rhizome),
Bryophyllum (leaf buds).
o Artificial → Cutting (Rose), Grafting (Mango), Layering
(Jasmine), Tissue culture.
2. Spore formation → Fungi (Rhizopus, Mucor, Ferns).

(ii) Sexual Reproduction

 Involves male gamete (pollen grain) and female gamete (ovule).

 Leads to variation.

Steps:

1. Pollination → Transfer of pollen to stigma.

o Self-pollination: Same flower/plant.
o Cross-pollination: Different plant (by wind, water, insects,
animals).
2. Fertilization → Fusion of male gamete (from pollen tube) with egg cell
inside ovule.
3. Double Fertilization (unique to angiosperms):
o 1 male gamete + egg cell → zygote.
o 1 male gamete + 2 polar nuclei → endosperm (nutritive tissue).
4. Seed & Fruit Formation →
o Ovule → Seed.
o Ovary → Fruit.

B. Quick Plant Repro Points (PYQ Focus)

 Bryophyllum → leaf buds.

 Sugarcane → stem cutting.
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 Wind pollination → Maize, Grass.

 Water pollination → Vallisneria, Hydrilla.
 Insect pollination → Rose, Sunflower.
 Double fertilization → only in Angiosperms.

Reproduction in Animals
A. Types of Reproduction

(i) Asexual Reproduction (mainly in simple animals)

1. Binary Fission → Amoeba, Paramecium.

2. Multiple Fission → Plasmodium.
3. Budding → Hydra, Yeast.
4. Fragmentation → Planaria, Sponges.
5. Regeneration → Starfish, Hydra.
👉 Only useful in lower organisms; offspring are clones.

(ii) Sexual Reproduction

 Involves two parents.

 Fusion of male gamete (sperm) and female gamete (ovum) →
zygote.
 Zygote develops into embryo.

B. Sexual Reproduction in Humans (brief)

1. Male reproductive system → Testes (sperms), Vas deferens, Penis.

2. Female reproductive system → Ovaries (eggs), Fallopian tubes,
Uterus, Vagina.
3. Fertilization → Internal, in fallopian tube.
4. Development → Zygote → Embryo → Foetus → Baby (in uterus, 9
months).

C. Fertilization Types in Animals

 External Fertilization → in water, outside female body (Frogs, Fish,

Amphibians).
 Internal Fertilization → inside female body (Reptiles, Birds,
Mammals).
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D. Oviparous vs. Viviparous

 Oviparous → Egg-laying (Fish, Amphibians, Reptiles, Birds).

 Viviparous → Give birth to young ones (Mammals, Humans).

E. Quick Animal Repro Points

 Hydra → budding.
 Amoeba → binary fission.
 Plasmodium → multiple fission.
 Earthworm & Leech → hermaphrodite (both sex organs in same body).
 Human pregnancy → ~280 days (9 months).
 Fertilization in humans → Fallopian tube.

Reproduction in Plants

1. Introduction

 Reproduction = process by which plants produce new individuals.

 Ensures continuity of species.
 Two main types: Asexual and Sexual reproduction.

2. Asexual Reproduction

 Involves single parent, no gametes, offspring are genetically

identical (clones).

A. Methods

1. Vegetative Propagation
o New plant grows from stem, root, or leaf.
o Natural:
 Stem → Sugarcane, Potato (tuber)
 Root → Sweet potato
 Leaf → Bryophyllum
o Artificial:
 Cutting → Rose, Hibiscus
 Grafting → Mango, Apple
 Layering → Jasmine, Grapevine
 Tissue culture → Orchids, Banana
2. Spore Formation
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In lower plants (ferns, mosses, fungi).

o
Spores → haploid → grow into new plant.
o
3. Budding
o In some algae and fungi.

3. Sexual Reproduction

 Involves fusion of male & female gametes → zygote → new plant.

 In flowering plants: reproduction involves flowers.

A. Flower Structure

Part Male / Female Function

Sepal Neither Protect flower bud
Petal Neither Attract pollinators
Stamen Male Produces pollen (microspores)
Carpel / Pistil Female Ovary → ovule, style, stigma
Ovule Female gamete Produces egg (megaspore)

B. Pollination

 Transfer of pollen to stigma.

 Types:
1. Self-pollination → same flower or plant (pea).
2. Cross-pollination → different plant (sunflower, hibiscus).
 Agents: Wind, water, insects, animals.

C. Fertilization

 Fusion of male gamete (sperm) and female gamete (egg) → zygote.

 Double fertilization (Angiosperms):
o 1 sperm + egg → zygote
o 1 sperm + 2 polar nuclei → endosperm (nutritive tissue)

D. Seed & Fruit Formation

 Ovule → Seed (contains embryo & stored food).

 Ovary → Fruit (protects seed, helps dispersal).
 Seed dispersal: wind, water, animals, explosive mechanism.
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E. Quick Points

 Bryophyllum → leaf buds

 Sugarcane → stem cutting
 Cross-pollination → increases genetic variation
 Wind pollinated → small, light pollen (Grass, Wheat)
 Insect pollinated → large, sticky pollen (Hibiscus, Sunflower)
 Double fertilization → unique to Angiosperms

Human Reproduction

1. Introduction

 Reproduction = process by which humans produce offspring to

continue the species.
 Sexual reproduction → involves male gamete (sperm) and female
gamete (ovum).
 Fertilization → zygote → embryo → fetus → baby.

2. Male Reproductive System

 Primary sex organ: Testes → produce sperms and testosterone.

 Accessory organs:
1. Epididymis → stores sperms.
2. Vas deferens → carries sperms.
3. Seminal vesicles, Prostate gland, Cowper’s gland → secrete
seminal fluid (nourishment & motility).
4. Penis → copulatory organ.

Sperm structure: Head (acrosome), midpiece (mitochondria), tail (flagellum).

3. Female Reproductive System

 Primary sex organs: Ovaries → produce ova and estrogen &

progesterone.
 Accessory organs:
1. Fallopian tubes (Oviducts) → site of fertilization.
2. Uterus → implantation & development of embryo.
3. Cervix → neck of uterus.
4. Vagina → birth canal & copulatory organ.
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4. Gametogenesis

1. Spermatogenesis → formation of sperm in testes.

2. Oogenesis → formation of ovum in ovary.

 Both involve meiosis → haploid gametes (23 chromosomes).

5. Fertilization

 Fusion of sperm + ovum → zygote (diploid).

 Location: Fallopian tube.
 Result: restores diploid number (46 chromosomes).

6. Development of Embryo

1. Zygote → undergoes cleavage → blastocyst.

2. Implantation → in uterine wall (~6–7 days).
3. Embryonic development:
o Formation of placenta → nutrient & waste exchange.
o Amniotic sac → protection.
4. Fetal development: 9 months → full-term baby.

7. Pregnancy & Birth

 Duration → ~280 days (9 months).

 Hormones involved: Estrogen, Progesterone, hCG.
 Parturition (childbirth): uterine contractions, baby delivered via
vagina.

8. Secondary Sexual Characteristics

 Male: Facial hair, deeper voice, muscular body, broad shoulders.

 Female: Breast development, menstrual cycle, wider hips, body fat
distribution.

9. Quick Exam Points

 Fertilization site → Fallopian tube.

 Male gamete → Sperm, Female gamete → Ovum.
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 Haploid gametes → 23 chromosomes; Zygote → 46 chromosomes.

 Menstrual cycle → ~28 days.
 Placenta → nutrient & waste exchange between mother & fetus.
 Hormone controlling pregnancy → Progesterone.

Human Brain

1. Introduction

 Brain = control center of the body, part of the central nervous

system (CNS).
 Located in cranial cavity, protected by skull, meninges, and
cerebrospinal fluid (CSF).
 Weighs ~1.4 kg in adults.

2. Structure of Human Brain

Divided into 4 main parts:

A. Cerebrum

 Largest part (~80% of brain weight).

 Functions:
o Voluntary movements.
o Sensory perception (touch, vision, hearing, taste, smell).
o Intelligence, reasoning, memory, learning.
 Cerebral cortex: Grey matter, highly folded (gyri & sulci).
 Left hemisphere: Logical thinking, language.
 Right hemisphere: Creativity, imagination.

B. Cerebellum

 Located at back of brain, below cerebrum.

 Functions:
o Maintains balance & posture.
o Coordinates voluntary movements (walking, running).
o Muscle tone regulation.

C. Brain Stem

 Connects brain with spinal cord.

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 Composed of:
1. Midbrain → vision & hearing reflexes.
2. Pons → connects cerebrum & cerebellum; regulates breathing.
3. Medulla oblongata → involuntary functions: heartbeat,
breathing, swallowing, vomiting.

D. Diencephalon

 Lies between cerebrum & brain stem.

 Composed of:
1. Thalamus → relay center for sensory signals to cerebrum.
2. Hypothalamus → controls:
 Hunger & thirst
 Body temperature
 Sleep-wake cycle
 Endocrine system via pituitary gland

3. Protective Structures

1. Skull → bony protection.

2. Meninges → 3 layers:
o Dura mater (outer)
o Arachnoid mater (middle)
o Pia mater (inner, attached to brain)
3. Cerebrospinal fluid (CSF) → cushions brain, removes wastes,
maintains pressure.

4. Functions of Brain

Part Function
Cerebrum Voluntary actions, intelligence, memory, senses
Cerebellum Balance, posture, coordination
Brain stem Involuntary actions (heartbeat, breathing)
Diencephalon Hormone control, sensory relay, homeostasis

5. Quick Exam Points

 Largest part → Cerebrum.

 Balance & coordination → Cerebellum.
 Vital centers → Medulla oblongata.
 Relay station → Thalamus.
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 Homeostasis → Hypothalamus.
 Grey matter → cortex, White matter → inner fibers.
 CSF → produced in choroid plexus of ventricles.

Human Endocrine System: Glands & Hormones

1. Introduction

 Endocrine glands → ductless glands that secrete hormones directly

into blood.
 Hormones → chemical messengers controlling growth, metabolism,
reproduction, and homeostasis.

2. Major Endocrine Glands, Hormones & Functions

Gland Hormone Function Deficiency / Disorder

Stimulates Dwarfism (deficiency),
Pituitary
Growth hormone growth, Gigantism (excess in
(Master
(GH) protein children), Acromegaly
gland)
synthesis (excess in adults)
Thyroid-stimulating Stimulates Hypothyroidism /
hormone (TSH) thyroid Hyperthyroidism
Adrenocorticotropic Stimulates Addison’s disease
hormone (ACTH) adrenal cortex (deficiency)
Stimulates
Follicle-stimulating
gamete Infertility
hormone (FSH)
production
Ovulation &
Luteinizing hormone
sex hormone Infertility
(LH)
production
Milk
Prolactin Inadequate lactation
production
Hypothyroidism → Goitre,
Thyroxine (T4), Cretinism (children),
Regulate
Thyroid Triiodothyronine Myxedema (adult),
metabolism
(T3) Hyperthyroidism →
Grave’s disease
Hypoparathyroidism →
Regulates
Tetany;
Parathyroid Parathormone (PTH) Ca²⁺ &
Hyperparathyroidism →
phosphate
Weak bones
Adrenal Cortisol Stress Addison’s disease
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Gland Hormone Function Deficiency / Disorder

Cortex hormone, (deficiency)
metabolism
Water & salt
Aldosterone Low BP if deficient
balance
Adrenaline
Adrenal Fight or flight Rare deficiency → low
(Epinephrine),
Medulla response stress response
Noradrenaline
Lowers blood Diabetes mellitus (Type
Pancreas Insulin
glucose I/II)
Raises blood
Glucagon Hypoglycemia if deficient
glucose
Regulates
Insomnia, circadian
Pineal gland Melatonin sleep-wake
rhythm disorder
cycle
Female
secondary
Ovary sexual Delayed puberty,
Estrogen
(female) characters, infertility
menstrual
cycle
Prepares
Progesterone uterus for Miscarriage risk
pregnancy
Male
secondary
Testes sexual Delayed puberty,
Testosterone
(male) characters, infertility
sperm
production

3. Key Points for Exams

 Pituitary = master gland → controls other glands.

 Thyroid → metabolism; parathyroid → calcium balance.
 Pancreas → endocrine (insulin, glucagon), exocrine (digestive
enzymes).
 Adrenal cortex → long-term stress, adrenal medulla → short-term
stress.
 Hormone excess or deficiency → specific disorders (memorize table).
 Insulin deficiency → Diabetes mellitus → high blood sugar, frequent
urination, excessive thirst.
 Iodine deficiency → Goitre.
 Vitamin D deficiency → Hypocalcemia, rickets.

Exocrine Glands
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1. Introduction

 Exocrine glands → secrete substances through ducts onto surface

of body or into body cavities.
 Secretions are not directly released into blood (unlike endocrine
glands).
 Types of secretions → enzymes, sweat, saliva, mucus, tears.

2. Major Exocrine Glands in Humans

Gland Secretion Function Location / Notes

Parotid,
Salivary Saliva (contains Starts digestion of
Submandibular,
glands amylase) starch
Sublingual
Sweat Sweat (water, Thermoregulation,
Skin (dermis)
glands salts) excretion of salts
Sebaceous Lubricates skin & Usually near hair
Sebum (oil)
glands hair follicles
Lacrimal Lubrication, cleaning,
Tears Eye (superolateral)
glands protection of eyes
Pancreatic juice
Pancreas
(enzymes: Digestion of carbs,
(exocrine Duct into duodenum
amylase, lipase, fats, proteins
part)
trypsin)
Liver Stored in gall
(exocrine Bile Emulsifies fats bladder, released into
function) duodenum
Mammary Nourishment for
Milk Modified sweat gland
glands newborn
Prostate Nourishment & Male reproductive
Seminal fluid
gland (male) transport of sperm system
Glands of Gastric juice
Protein digestion Stomach lining
stomach (HCl + pepsin)
Glands of Intestinal juice Digestion of carbs,
Small intestine
intestine (enzymes) proteins, fats

3. Key Characteristics

 Have ducts to carry secretion.

 Can be unicellular (Goblet cells → mucus) or multicellular (salivary
glands, pancreas).
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 Function in digestion, lubrication, thermoregulation, protection,

and reproduction.

4. Quick Exam Points

 Exocrine = ducts; Endocrine = ductless.

 Pancreas → both endocrine (insulin, glucagon) & exocrine (digestive
enzymes).
 Sebaceous glands → oily secretion; Sweat glands → watery secretion.
 Gastric glands → protein digestion; Salivary glands → starch
digestion.

Chromosomal Disorders in Humans

A. Introduction

 Caused by changes in chromosome number or structure.

 Humans normally have 46 chromosomes (23 pairs) → 22 pairs
autosomes + 1 pair sex chromosomes.

B. Types of Chromosomal Disorders

Disorder Chromosomal Cause Key Features

Mental retardation, flat face,
Down Syndrome Extra chromosome 21 (47
short stature, almond-shaped
(Trisomy 21) total)
eyes, heart defects
Turner Short stature, webbed neck,
Female with single X (45, X)
Syndrome sterile, no menstruation
Tall, small testes, sterile,
Klinefelter
Male with XXY (47, XXY) female secondary sexual
Syndrome
characters
Edward’s
Severe developmental delay,
Syndrome Extra chromosome 18
heart defects, short lifespan
(Trisomy 18)
Patau Cleft lip, polydactyly, severe
Syndrome Extra chromosome 13 mental retardation, short
(Trisomy 13) lifespan
Cri-du-chat Cat-like cry in infants, mental
Deletion in chromosome 5
syndrome retardation, small head
Chronic Reciprocal translocation
Myeloid between 9 & 22 Cancer of white blood cells
Leukemia (CML) (Philadelphia chromosome)
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C. Key Exam Points

 Trisomy → extra chromosome.

 Monosomy → missing chromosome (Turner).
 Sex chromosome abnormalities → affect sexual characteristics &
fertility.
 Deletion → loss of a chromosome segment.
 Translocation → exchange between chromosomes.

Vitamins and Deficiency Diseases

A. Fat-Soluble Vitamins

Vitamin Function Deficiency Disease Food Source

Night blindness,
Vitamin A Vision (rhodopsin), Carrot, liver,
xerophthalmia,
(Retinol) skin, immunity egg, milk
keratomalacia
Calcium &
Rickets (children), Sunlight, fish
Vitamin D phosphorus
Osteomalacia liver oil, eggs,
(Calciferol) absorption, bone
(adults) milk
health
Antioxidant, Vegetable oils,
Vitamin E
prevents cell Sterility, anemia nuts, leafy
(Tocopherol)
damage vegetables
Leafy
Vitamin K Hemorrhage, delayed vegetables,
Blood clotting
(Phylloquinone) clotting spinach,
cabbage

B. Water-Soluble Vitamins

Vitamin Function Deficiency Disease Food Source

Carbohydrate
Vitamin B1 Beriberi (nerve Whole grains,
metabolism, nerve
(Thiamine) disorder, edema) legumes
function
Milk, eggs,
Vitamin B2 Energy metabolism, Cracks at mouth
green leafy
(Riboflavin) skin health corners, dermatitis
vegetables
Vitamin B3 Energy metabolism, Pellagra (dermatitis, Meat, fish,
(Niacin) DNA repair diarrhea, dementia) whole grains
Vitamin B5 Coenzyme A Rare, fatigue, Meat, eggs,
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Vitamin Function Deficiency Disease Food Source

(Pantothenic formation hypoglycemia cereals
acid)
Vitamin B6 Amino acid Anemia, Fish, poultry,
(Pyridoxine) metabolism convulsions banana
Vitamin B12 RBC formation,
Pernicious anemia Meat, eggs, milk
(Cobalamin) nerve function
Scurvy (bleeding
Vitamin C Collagen formation, Citrus fruits,
gums, weak
(Ascorbic acid) antioxidant tomato, guava
immunity)
Megaloblastic Green leafy
RBC formation,
Folic Acid (B9) anemia, neural tube vegetables,
DNA synthesis
defects legumes

C. Quick Exam Points

 Fat-soluble → A, D, E, K → stored in liver & fat, excess may be toxic.

 Water-soluble → B-complex, C → excess excreted in urine.
 Night blindness → Vitamin A deficiency.
 Rickets → Vitamin D deficiency.
 Scurvy → Vitamin C deficiency.
 Beriberi → Vitamin B1 deficiency.
 Pernicious anemia → Vitamin B12 deficiency.

Food Chains and Food Webs

1. Introduction

 Food chain = sequence of organisms where each organism eats the

previous one and is eaten by the next.
 Represents flow of energy and nutrients in an ecosystem.
 Energy flow is unidirectional (sun → producers → consumers →
decomposers).

2. Components of Food Chain

Component Role Example

Grass,
Makes own food using
Producer (Autotrophs) Phytoplankton,
sunlight (photosynthesis)
Trees
Primary Consumer Rabbit, Cow,
Eats producers
(Herbivore) Zooplankton
Secondary Consumer Eats primary consumers Snake, Frog, Small
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Component Role Example

(Carnivore / Omnivore) fish
Tertiary Consumer Eats secondary consumers Hawk, Large fish
Decomposer / Breaks down dead matter & Fungi, Bacteria,
Detritivore recycles nutrients Earthworms

3. Types of Food Chains

1. Grazing food chain

o Begins with living plants → herbivores → carnivores.
o Example: Grass → Rabbit → Snake → Hawk
2. Detritus food chain
o Begins with dead organic matter → detritivores →
decomposers → carnivores.
o Example: Dead leaves → Earthworm → Frog → Snake

4. Food Web

 Interconnected food chains in an ecosystem.

 More realistic → shows multiple feeding relationships.
 Provides stability to ecosystem.

5. Trophic Levels

 Level 1: Producers → plants (autotrophs).

 Level 2: Primary consumers → herbivores.
 Level 3: Secondary consumers → carnivores.
 Level 4: Tertiary consumers → top carnivores.
 Level 5: Decomposers → fungi, bacteria.

Note: Only ~10% of energy is transferred to the next level (Energy Pyramid /
10% Law).

6. Energy Flow

 Energy flows from sun → producer → herbivore → carnivore →

decomposer.
 Energy decreases at each trophic level.
 Biomagnification: Toxins (like pesticides) increase in concentration at
higher trophic levels.
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7. Quick Exam Points

 Producer → green plants, autotroph.

 Consumer → heterotroph, depends on other organisms.
 Decomposer → recycle nutrients.
 Food chain → linear; Food web → network.
 Energy transfer efficiency → ~10% per trophic level.
 Top predator → apex consumer, e.g., Hawk.

1. Aquatic Ecosystem

Introduction

 Ecosystem in water bodies: lakes, ponds, rivers, oceans.

 Organisms live in water and depend on dissolved nutrients.

Components

1. Producers: Phytoplankton, algae, submerged plants.

2. Primary consumers: Zooplankton, small fish.
3. Secondary consumers: Larger fish, frogs.
4. Tertiary consumers: Sharks, birds, crocodiles.
5. Decomposers: Bacteria, fungi, detritus feeders.

Characteristics

 Energy flow: Sun → Phytoplankton → Zooplankton → Fish → Apex

predator.
 Light penetration, dissolved oxygen, and salinity affect species
distribution.

2. Terrestrial Ecosystem

Introduction

 Ecosystem on land, includes forests, grasslands, tundra, mountains.

Components

1. Producers: Trees, shrubs, grasses.

2. Primary consumers: Herbivores – deer, elephants, insects.
3. Secondary consumers: Carnivores – fox, tiger, birds.
4. Tertiary consumers: Apex predators.
5. Decomposers: Bacteria, fungi, earthworms.
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Characteristics

 Energy flow: Sun → Producer → Herbivore → Carnivore →

Decomposer.
 Soil type, rainfall, and temperature affect vegetation.
 Biodiversity is highest in tropical forests.

3. Detritus Food Chain (DFC)

Introduction

 Begins with detritus (dead organic matter) instead of live plants.

 Found in both aquatic and terrestrial ecosystems.

Components

1. Detritus (Dead organic matter) → leaves, dead animals, organic

waste.
2. Detritivores (Primary consumers) → Earthworms, dung beetles,
scavengers.
3. Secondary consumers → Predators that feed on detritivores (frogs,
snakes).
4. Tertiary consumers → Apex predators feeding on secondary
consumers.
5. Decomposers → Bacteria, fungi → recycle nutrients into soil.

Characteristics

 Nutrients recycled efficiently.

 Energy flow: Detritus → Detritivores → Carnivores → Decomposers.
 Important in soil fertility and ecosystem stability.

4. Key Comparison Table: Aquatic vs Terrestrial vs DFC

Feature Aquatic Terrestrial DFC (Detritus)

Sun →
Energy source Sun → Plants Dead organic matter
Phytoplankton
Primary
Phytoplankton Plants Detritus (non-living)
producer
Herbivores, Detritivores,
Consumers Zooplankton, fish
carnivores scavengers
Bacteria, fungi,
Decomposers Bacteria, fungi Bacteria, fungi
earthworms
Role Food & energy flow Food & energy Nutrient recycling, soil
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Feature Aquatic Terrestrial DFC (Detritus)

in water flow on land fertility
Leaf litter →
Examples Pond, river, ocean Forest, grassland Earthworms → Frogs
→ Snakes