1. What subject - Biology, Chemistry, Physics, Mathematics, History, Geography, etc.?
2. What topic or chapter - e.g., "photosynthesis," "quadratic equations," "French Revolution"?
3. What do you need - explanation, summary, key points, solved examples, diagrams, or something else?

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🎯 NEET Minor Test - 5th July 2026

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⚡ PHYSICS - Units and Dimensions

1. Physical Quantities

• Fundamental (Base) quantities: Cannot be derived - Length, Mass, Time, Electric Current, Temperature, Luminous Intensity, Amount of Substance
• Derived quantities: Derived from fundamental quantities (e.g., velocity = length/time)

2. SI System - 7 Base Units

Supplementary units: Radian (rad) - plane angle; Steradian (sr) - solid angle

3. Important Prefixes

4. Dimensions

• Represented using [M], [L], [T], [A], [K], [cd], [mol]
• Dimension of a quantity = powers to which base quantities are raised

5. Principle of Homogeneity

• Every term in a physical equation must have the same dimensions
• Used to: (a) check correctness of equations, (b) derive relations, (c) convert units

6. Dimensionless Quantities

• Pure numbers, angles (in radians), relative density, strain, refractive index, e^x, log x, sin θ

7. Significant Figures - Rules

1. All non-zero digits are significant
2. Zeros between non-zero digits are significant (e.g., 2005 → 4 sig figs)
3. Trailing zeros after decimal are significant (e.g., 3.500 → 4 sig figs)
4. Leading zeros are NOT significant (e.g., 0.0023 → 2 sig figs)

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🧪 CHEMISTRY

Part A: Mole Concept (Some Basic Concepts of Chemistry)

Laws of Chemical Combination

1. Law of Conservation of Mass - Matter is neither created nor destroyed
2. Law of Definite Proportions (Proust) - A compound always has elements in fixed mass ratio
3. Law of Multiple Proportions (Dalton) - Masses of one element combining with fixed mass of another are in simple whole-number ratios
4. Law of Gaseous Volumes (Gay-Lussac) - Gases combine in simple whole-number volume ratios
5. Avogadro's Law - Equal volumes of gases at same T & P contain equal number of molecules

Atomic and Molecular Mass

• 1 amu (atomic mass unit) = 1/12 the mass of ¹²C atom = 1.66 × 10⁻²⁷ kg
• Atomic mass = mass of one atom in amu
• Molecular mass = sum of atomic masses of all atoms in a molecule

Mole Concept - THE MOST IMPORTANT PART

• 1 mole = 6.022 × 10²³ particles (Avogadro's number, Nₐ)
• Molar mass = mass of 1 mole in grams (numerically = atomic/molecular mass)

Number of moles (n) = Given mass (W) / Molar mass (M)
Number of particles = n × 6.022 × 10²³
Volume at STP (for gas) = n × 22.4 L

Percentage Composition & Empirical Formula

• % of element = (mass of element in 1 mole of compound / molar mass) × 100
• Empirical formula = simplest whole-number ratio of atoms
• Molecular formula = actual number of atoms (= n × empirical formula)
• n = Molar mass / Empirical formula mass

Stoichiometry

• Limiting reagent = reactant consumed first; determines amount of product
• Always calculate moles from given mass before comparing

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Part B: Atomic Structure

Sub-atomic Particles

Atomic Models

• Atom = positively charged sphere with electrons embedded in it
• Disproved by Rutherford's experiment

• Gold foil experiment - α-particles fired at gold foil
• Conclusions:
  • Atom is mostly empty space
  • Nucleus is small, dense, positively charged
  • Electrons revolve around the nucleus
• Failure: Could not explain atomic spectra; electrons should spiral inward (unstable)

• Electrons revolve in fixed circular orbits (shells) with definite energy
• Energy is quantized: E = -13.6/n² eV (for hydrogen)
• Electron jumps: absorbs energy → excited; emits energy → falls to lower orbit
• Radius of nth orbit: rₙ = 0.529 × n² Å (for H)
• Energy of nth orbit: Eₙ = -13.6/n² eV

Quantum Numbers (for NEET - 4 types)

• s: l=0, 1 orbital; p: l=1, 3 orbitals; d: l=2, 5 orbitals; f: l=3, 7 orbitals

Electronic Configuration Rules

1. Aufbau Principle - Fill orbitals in order of increasing energy (1s < 2s < 2p < 3s...)
2. Pauli Exclusion Principle - No two electrons can have all 4 same quantum numbers; max 2 electrons per orbital with opposite spins
3. Hund's Rule - Electrons occupy orbitals singly before pairing; all unpaired electrons have same spin

Energy Order of Filling (n+l rule)

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🌿 BIOLOGY - BOTANY

Cell: The Unit of Life (Ch. 8, NCERT Class 11)

Cell Theory

• Robert Hooke (1665) - first described cells (in cork)
• Leeuwenhoek - first observed living cells
• Cell Theory (Schleiden + Schwann, 1838-39): All living organisms are composed of cells; cell is the basic unit of life
• Virchow (1855) added: New cells arise from pre-existing cells ("Omnis cellula e cellula")

Prokaryotic vs. Eukaryotic Cells

Cell Organelles - Key Points

• Fluid mosaic model (Singer & Nicolson, 1972)
• Selectively permeable; made of phospholipid bilayer + proteins
• Cholesterol provides fluidity

• Primary wall: cellulose (flexible)
• Secondary wall: lignin (rigid)
• Middle lamella: calcium pectate (cements adjacent cells)
• Plasmodesmata: cytoplasmic connections between cells

• Bounded by nuclear envelope (double membrane with nuclear pores)
• Contains nucleoplasm, chromatin, nucleolus
• Nucleolus: site of rRNA synthesis
• Chromosomes: DNA + histone proteins

• RER (rough): has ribosomes; synthesizes proteins for secretion
• SER (smooth): no ribosomes; lipid synthesis, detoxification

• Stack of flattened sacs (cisternae)
• Cis face (forming face) - receives from ER; Trans face (maturing face) - releases vesicles
• Functions: glycosylation, packaging, secretion; forms lysosomes

• "Powerhouse of the cell" - site of ATP synthesis (aerobic respiration)
• Double membrane: outer membrane + inner membrane (cristae)
• Matrix contains: mtDNA, ribosomes (70S), enzymes of Krebs cycle
• Semi-autonomous (own DNA + ribosomes)

• Double membrane; inner membrane encloses stroma
• Thylakoids arranged in grana; light reactions occur on thylakoid membrane
• Dark reactions (Calvin cycle) in stroma
• Contain 70S ribosomes; own DNA

• Membrane-bound; contain hydrolytic enzymes
• "Suicidal bags of the cell" (de Duve)
• Digest worn-out organelles (autophagy); involved in phagocytosis

• Large central vacuole in plant cells (up to 90% of cell volume)
• Bounded by tonoplast; contains cell sap
• Maintains turgor pressure

• Absent in higher plant cells; present in animal cells
• Form spindle fibres during cell division
• Made of tubulin protein (9+0 triplet arrangement)

• Site of protein synthesis
• 80S in eukaryotes (60S + 40S); 70S in prokaryotes (50S + 30S)
• Made of rRNA + proteins

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Cell Cycle and Cell Division (Upto Mitosis)

Cell Cycle

• G₁ phase (First Gap): Cell grows; organelle duplication; RNA/protein synthesis
• S phase (Synthesis): DNA replication; histone synthesis; chromosome number stays same but DNA doubles
• G₂ phase (Second Gap): Further growth; preparation for division; tubulin synthesis
• M phase (Mitosis): Actual cell division

Cells that stop dividing enter G₀ phase (quiescent/senescent)

Interphase

Mitosis (Equational Division)

• Occurs in: somatic (body) cells
• Result: 2 genetically identical daughter cells with same chromosome number as parent (2n → 2n)

Phases of Mitosis:

• Chromatin condenses into visible chromosomes
• Each chromosome consists of 2 sister chromatids joined at centromere
• Nucleolus disappears; nuclear envelope breaks down
• Spindle apparatus begins to form

• Chromosomes align at metaphase plate (equatorial plane)
• Spindle fibres attach to centromeres via kinetochores
• Chromosomes are maximally condensed - BEST STAGE TO COUNT CHROMOSOMES

• Centromeres split; sister chromatids separate
• Chromatids (now called chromosomes) move to opposite poles
• Cell elongates; V, J, L, I shapes depending on centromere position

• Chromosomes reach poles; start to decondense
• Nuclear envelope reforms; nucleolus reappears
• Spindle fibres disappear

Cytokinesis (after telophase):

• Animals: cleavage furrow (actin-myosin ring)
• Plants: cell plate forms (from Golgi vesicles, phragmoplast); becomes new cell wall

Significance of Mitosis

• Growth and repair of tissues
• Maintains chromosome number (2n → 2n)
• Produces genetically identical cells

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🫁 BIOLOGY - ZOOLOGY

Breathing and Exchange of Gases (Ch. 17, NCERT Class 11)

Human Respiratory System - Structure

• Nostrils → nasal cavity (lined with mucus and cilia - filter, warm, moisten air)
• Pharynx → larynx (voice box; epiglottis prevents food entry)
• Trachea (windpipe): C-shaped cartilaginous rings; lined with cilia + goblet cells

• Bronchi → bronchioles → alveolar ducts → alveoli
• Alveoli: actual site of gas exchange; ~300 million in lungs; immense surface area (~75 m²)
• Lungs enclosed by pleura (double membrane); pleural fluid reduces friction

Mechanism of Breathing

• Diaphragm contracts → moves down; external intercostal muscles contract → ribs move up + out
• Thoracic volume increases → intrapulmonary pressure decreases → air flows in

• Diaphragm relaxes → moves up; internal intercostal muscles contract
• Thoracic volume decreases → pressure increases → air flows out

Lung Volumes and Capacities

VC = IRV + TV + ERV (cannot be measured by spirometry alone) TLC = VC + RV (dead air is included)

Exchange of Gases

• O₂ diffuses from alveoli → blood (pO₂ alveoli = 104 mmHg; pO₂ blood = 40 mmHg)
• CO₂ diffuses from blood → alveoli (pCO₂ blood = 45 mmHg; pCO₂ alveoli = 40 mmHg)
• Diffusion membrane: alveolar epithelium + basement membrane + capillary endothelium (< 1 mm thick)

• O₂ diffuses from blood → tissues; CO₂ from tissues → blood

Transport of Gases

• ~97% as oxyhaemoglobin (HbO₂) in RBCs
• ~3% dissolved in plasma
• Haemoglobin: 4 subunits; each binds 1 O₂; cooperative binding
• Oxygen dissociation curve: sigmoidal (S-shaped)
  • Right shift (Bohr effect): increased CO₂, decreased pH, increased temp → Hb releases O₂ more easily (to active tissues)

• ~70% as bicarbonate ions (HCO₃⁻) in plasma (most important)
• ~20-25% as carbaminohaemoglobin (bound to Hb)
• ~7% dissolved in plasma

Chloride Shift (Hamburger phenomenon): When CO₂ enters RBC → forms HCO₃⁻ → moves to plasma; Cl⁻ enters RBC to maintain electrical neutrality

Regulation of Breathing

• Respiratory Rhythm Centre: medulla oblongata (primary center)
• Pneumotaxic Centre: pons - moderates respiratory rhythm
• Chemoreceptors: in aortic arch, carotid body (peripheral) and medulla (central)
  • Sensitive to CO₂, H⁺, and O₂ levels
  • Increased CO₂ / decreased pH → increased breathing rate

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📌 Quick Revision Mnemonics

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✅ High-Yield NEET Points to Remember

1. Dimensionless quantities: angle, relative density, strain, refractive index
2. 1 mole = 6.022 × 10²³ particles = molar mass in grams = 22.4 L at STP (gas)
3. Ribosomes: 70S in prokaryotes/mitochondria/chloroplasts; 80S in eukaryotic cytoplasm
4. Metaphase: best stage to count chromosomes (most condensed)
5. Centromere splits in Anaphase (not in meiosis I, but in meiosis II and mitosis)
6. Alveoli: ~300 million; actual site of gas exchange
7. Residual Volume: cannot be expelled even after max expiration - dead air
8. Bohr effect: CO₂ increases → pH falls → Hb releases O₂ (right shift of dissociation curve)
9. Medulla oblongata controls respiratory rhythm
10. Plant cytokinesis = cell plate; Animal cytokinesis = cleavage furrow

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🔬 Diagram 1 - Eukaryotic Animal Cell Organelles

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🧬 Diagram 2 - Phases of Mitosis

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📝 Key things to notice in these diagrams for NEET:

• RER has ribosomes on its surface; SER does not
• Mitochondria has double membrane - outer smooth + inner folded (cristae)
• Golgi apparatus has a distinct cis face (receiving) and trans face (secreting)
• Centrosome with centrioles is present in animal cells, absent in higher plants

• Prophase - chromatin condenses, nuclear envelope breaks down
• Metaphase - chromosomes at equatorial plate (best stage to count chromosomes!)
• Anaphase - centromere splits, chromatids pulled to poles
• Telophase - nuclear envelope reforms, chromosomes decondense
• Cytokinesis - cell plate in plants / cleavage furrow in animals