🔬 SCIENCE COMPLETE MASTERY GUIDE 🧪

Physics | Chemistry | Biology | Class 9-12

Science is the systematic study of the natural world through observation, experimentation, and evidence-based reasoning. This comprehensive mastery guide covers the complete science curriculum from Class 9 to Class 12, including Physics (mechanics, electricity, optics, modern physics), Chemistry (organic, inorganic, physical chemistry), and Biology (botany, zoology, human physiology). Master all fundamental laws, chemical reactions, biological processes, 50+ solved numerical problems with step-by-step solutions, important diagrams with proper labels, practical experiments explained thoroughly, common viva questions with model answers, formula derivations, memory tricks for complex concepts, and exam strategies to score 95%+ in boards. Whether you're preparing for CBSE, ICSE, or state boards, this guide provides crystal-clear explanations of every concept from basic to advanced level. Perfect for students who want to build strong conceptual foundation, ace their board exams, and prepare for competitive exams like NEET, JEE, AIIMS simultaneously!

⚡ PHYSICS - CLASS 9-10 FOUNDATION

Motion, Force, Energy, Electricity, Light & Sound fundamentals

🎯 Motion & Force (Mechanics)

1. Motion in Straight Line

Key Definitions: Distance: Total path length covered (scalar)
Displacement: Shortest distance between initial and final position (vector)
Speed: Distance/Time (scalar)
Velocity: Displacement/Time (vector)
Acceleration: Change in velocity/Time

Equations of Motion (Uniform Acceleration):
v = u + at
s = ut + (1/2)at²
v² = u² + 2as

Where: u = initial velocity, v = final velocity,
a = acceleration, t = time, s = displacement

🔍 Numerical 1: A car accelerates from 10 m/s to 30 m/s in 5 seconds. Find acceleration and distance covered.

Given: u = 10 m/s, v = 30 m/s, t = 5 s

Finding acceleration:
v = u + at
30 = 10 + a(5)
20 = 5a
a = 4 m/s²

Finding distance:
s = ut + (1/2)at²
s = 10(5) + (1/2)(4)(5)²
s = 50 + (1/2)(4)(25)
s = 50 + 50 = 100 m

Answer: Acceleration = 4 m/s², Distance = 100 m

Advertisement

2. Newton's Laws of Motion

• First Law (Law of Inertia): An object remains at rest or in uniform motion unless acted upon by external force
• Second Law: F = ma (Force = mass × acceleration)
• Third Law: For every action, there is equal and opposite reaction

Important Force Formulas:
Weight: W = mg (where g = 9.8 m/s²)
Friction: f = μN (μ = coefficient of friction, N = normal force)
Momentum: p = mv
Impulse: J = F×t = Change in momentum = Δp

Conservation of Momentum:
Total momentum before collision = Total momentum after collision
m&sub1;u&sub1; + m&sub2;u&sub2; = m&sub1;v&sub1; + m&sub2;v&sub2;

🔍 Numerical 2: A force of 20 N acts on a body of mass 5 kg. Find acceleration.

Using F = ma
20 = 5 × a
a = 20/5 = 4 m/s²

Answer: Acceleration = 4 m/s²

3. Gravitation

Universal Law of Gravitation:
F = G(m&sub1;m&sub2;)/r²
Where G = 6.67 × 10^-11 Nm²/kg² (Universal gravitational constant)

Acceleration due to gravity:
g = GM/R² (on Earth's surface)
M = Mass of Earth = 6 × 10²⁴ kg
R = Radius of Earth = 6.4 × 10⁶ m
g = 9.8 m/s²

Weight and Mass:
Weight = mg (changes with location)
Mass = constant everywhere

💡 Memory Trick - Equations of Motion:

Remember "VUT-SAT-VUAS": v=u+at, s=ut+(1/2)at², v²=u²+2as. First letters match!

💡 Electricity & Magnetism

1. Electric Current & Circuits

Basic Electrical Quantities:
Current (I): Rate of flow of charge, I = Q/t
Unit: Ampere (A), 1 A = 1 Coulomb/second

Voltage (V): Potential difference, Work done per unit charge
Unit: Volt (V), 1 V = 1 Joule/Coulomb

Resistance (R): Opposition to current flow
Unit: Ohm (Ω)

Ohm's Law (Most Important!):
V = IR

Power:
P = VI = I²R = V²/R
Unit: Watt (W)

Energy Consumed:
E = Pt = VIt
Unit: Joule (J) or kilowatt-hour (kWh)
1 kWh = 3.6 × 10⁶ J = 1 Unit (electricity bill)

🔍 Numerical 3: A 100W bulb is used for 5 hours daily for 30 days. Find units consumed and cost at ₹6 per unit.

Power = 100 W = 0.1 kW
Time = 5 hours/day × 30 days = 150 hours

Energy = Power × Time
E = 0.1 × 150 = 15 kWh = 15 Units

Cost = 15 × ₹6 = ₹90

Answer: 15 Units consumed, Cost = ₹90

2. Series and Parallel Circuits

Series Connection:
Current same: I = I&sub1; = I&sub2; = I&sub3;
Voltage adds: V = V&sub1; + V&sub2; + V&sub3;
Resistance adds: R = R&sub1; + R&sub2; + R&sub3;

Parallel Connection:
Voltage same: V = V&sub1; = V&sub2; = V&sub3;
Current adds: I = I&sub1; + I&sub2; + I&sub3;
Resistance: 1/R = 1/R&sub1; + 1/R&sub2; + 1/R&sub3;

For 2 resistors in parallel:
R = (R&sub1;R&sub2;)/(R&sub1; + R&sub2;)

🔍 Numerical 4: Three resistors 2Ω, 3Ω, 6Ω are connected in parallel. Find equivalent resistance.

Using 1/R = 1/R&sub1; + 1/R&sub2; + 1/R&sub3;
1/R = 1/2 + 1/3 + 1/6
1/R = 3/6 + 2/6 + 1/6
1/R = 6/6 = 1
R = 1 Ω

Answer: Equivalent resistance = 1 Ω

3. Magnetic Effects of Current

• Magnetic Field: Region around magnet where magnetic force is experienced
• Right Hand Thumb Rule: Thumb = current direction, Fingers = magnetic field direction
• Fleming's Left Hand Rule: First finger = Field, seCond finger = Current, thuMb = Motion (Force)
• Electromagnetic Induction: Current induced when magnetic field changes through coil
• Fleming's Right Hand Rule: For generator - thuMb = Motion, First finger = Field, seCond finger = Current

Force on Current-Carrying Conductor:
F = BIL sin θ
Where: B = magnetic field, I = current,
L = length of conductor, θ = angle

For θ = 90° (perpendicular): F = BIL (maximum)

⚠️ Common Mistake:

Students confuse Fleming's Left Hand Rule (motor) with Right Hand Rule (generator). Remember: Left for motor (electrical → mechanical), Right for generator (mechanical → electrical)!

🌊 Light & Sound

1. Reflection of Light

Laws of Reflection:
1. Angle of incidence = Angle of reflection (i = r)
2. Incident ray, reflected ray, and normal lie in same plane

Mirror Formula:
1/f = 1/v + 1/u

Magnification:
m = -v/u = h'/h

Where: f = focal length, u = object distance,
v = image distance, h = object height, h' = image height

Sign Convention:
• Distances measured from pole
• Left side = negative, Right side = positive
• Above principal axis = positive, Below = negative

🔍 Numerical 5: Object at 30 cm from concave mirror of focal length 20 cm. Find image position and magnification.

Given: u = -30 cm (object on left), f = -20 cm (concave mirror)

Using 1/f = 1/v + 1/u
1/(-20) = 1/v + 1/(-30)
1/v = 1/(-20) + 1/30
1/v = -3/60 + 2/60 = -1/60
v = -60 cm

Magnification: m = -v/u = -(-60)/(-30) = -2

Answer: Image at 60 cm (same side as object), magnified 2 times, inverted (m negative)

2. Refraction of Light

Snell's Law:
n&sub1; sin i = n&sub2; sin r

Refractive Index:
n = c/v = (Speed of light in vacuum)/(Speed in medium)
n = sin i/sin r (relative refractive index)

Lens Formula:
1/f = 1/v - 1/u

Power of Lens:
P = 1/f (in meters)
Unit: Dioptre (D), 1 D = 1 m^-1

For combination of lenses:
P = P&sub1; + P&sub2; + P&sub3;

3. Sound Waves

Wave Properties:
Speed of sound: v = νλ
Where: v = velocity, ν = frequency, λ = wavelength

Speed in air = 343 m/s (at 20°C)
Speed increases with temperature

Range of Hearing:
Human: 20 Hz to 20,000 Hz
Infrasound: Below 20 Hz
Ultrasound: Above 20,000 Hz

Echo Condition:
Minimum distance = vt/2
For echo to be heard: t ≥ 0.1 s
Minimum distance = (343 × 0.1)/2 = 17.15 m

💡 Memory Trick for Lens:

Convex lens = Converging = Positive focal length. Concave lens = Diverging = Negative focal length. "Con-VEX = con-VERGING" - VEX sounds like VERGE!

Advertisement

🧲 PHYSICS - CLASS 11-12 ADVANCED

Mechanics, Thermodynamics, Waves, Electromagnetism, Modern Physics

🚀 Mechanics & Energy

1. Work, Energy & Power

Work Done:
W = F·s cos θ (scalar product)
For θ = 0°: W = Fs (maximum)
For θ = 90°: W = 0
For θ = 180°: W = -Fs
Unit: Joule (J), 1 J = 1 Nm

Kinetic Energy:
KE = (1/2)mv²

Potential Energy:
Gravitational: PE = mgh
Elastic: PE = (1/2)kx² (k = spring constant)

Work-Energy Theorem:
Work done = Change in kinetic energy
W = KE(final) - KE(initial)

Conservation of Energy:
Total Energy = KE + PE = constant

Power:
P = W/t = F·v
Unit: Watt (W), 1 W = 1 J/s

🔍 Numerical 6: A body of mass 2 kg falls from height 20 m. Find velocity just before hitting ground.

Using conservation of energy:
PE at top = KE at bottom
mgh = (1/2)mv²
gh = (1/2)v²
v² = 2gh
v² = 2 × 10 × 20 = 400
v = 20 m/s

Answer: Velocity = 20 m/s

2. Rotational Motion

Angular Quantities:
Angular displacement: θ (radian)
Angular velocity: ω = dθ/dt = v/r
Angular acceleration: α = dω/dt = a/r

Relation with linear motion:
v = rω
a = rα

Moment of Inertia (I):
I = Σmr² (analogous to mass in linear motion)

Ring: I = MR²
Disc: I = (1/2)MR²
Sphere (solid): I = (2/5)MR²
Rod (about center): I = (1/12)ML²

Torque:
τ = r × F = rF sin θ
τ = Iα (analogous to F = ma)

Angular Momentum:
L = Iω
Conservation: L = constant (no external torque)

3. Gravitation (Advanced)

Gravitational Potential Energy:
U = -GMm/r
(negative because force is attractive)

Escape Velocity:
v(e) = √(2GM/R) = √(2gR)
For Earth: v(e) = 11.2 km/s

Orbital Velocity:
v(o) = √(GM/r) = √(gR)

Satellite Period:
T = 2π√(r³/GM)

Kepler's Laws:
1. Planets move in elliptical orbits
2. Areal velocity constant (dA/dt = constant)
3. T² ∝ r³

🔥 High Weightage Alert!

Work-Energy theorem and Conservation laws are favorite board exam topics! Practice 10+ numericals on energy conservation. Easy 5-6 marks!

🌡️ Thermodynamics & Heat

1. Heat Transfer

Heat Capacity:
Q = mcΔT
Where: Q = heat, m = mass, c = specific heat, ΔT = temperature change

Latent Heat:
Q = mL
L(fusion) for ice = 334 kJ/kg
L(vaporization) for water = 2260 kJ/kg

Thermal Expansion:
Linear: ΔL = αLΔT
Area: ΔA = 2αAΔT
Volume: ΔV = γVΔT (γ = 3α)

Heat Conduction:
Q/t = kA(T₁ - T₂)/d
Where k = thermal conductivity

2. Laws of Thermodynamics

First Law (Energy Conservation):
ΔQ = ΔU + ΔW
Heat supplied = Increase in internal energy + Work done

For different processes:
• Isothermal (T = constant): ΔU = 0, ΔQ = ΔW
• Adiabatic (Q = 0): ΔU = -ΔW
• Isochoric (V = constant): ΔW = 0, ΔQ = ΔU
• Isobaric (P = constant): ΔQ = nC(p)ΔT

Work Done by Gas:
W = PΔV (for isobaric)
W = nRT ln(V₂/V₁) (for isothermal)

Second Law:
Heat cannot spontaneously flow from cold to hot
Entropy of universe always increases

3. Kinetic Theory of Gases

Ideal Gas Equation:
PV = nRT
Where: R = 8.314 J/(mol·K)

Kinetic Energy of Gas:
Average KE per molecule = (3/2)kT
Where k = Boltzmann constant = 1.38 × 10^-23 J/K

RMS Speed:
v(rms) = √(3RT/M) = √(3P/ρ)

Degrees of Freedom:
Monatomic: f = 3
Diatomic: f = 5
Polyatomic: f = 6

Molar Heat Capacities:
C(v) = (f/2)R
C(p) = C(v) + R
γ = C(p)/C(v)

🔍 Numerical 7: 2 moles of ideal gas at 300K. Find total internal energy.

For diatomic gas (like O₂, N₂): f = 5
Internal energy: U = (f/2)nRT
U = (5/2) × 2 × 8.314 × 300
U = 2.5 × 2 × 8.314 × 300
U = 12,471 J ≈ 12.5 kJ

Answer: Internal energy = 12.5 kJ

💡 Memory Trick - Thermodynamic Processes:

"I-A-I-I" = Isothermal (T constant), Adiabatic (Q=0), Isochoric (V constant), Isobaric (P constant). Remember sequence!

⚡ Electrostatics & Capacitance

1. Electric Field & Potential

Coulomb's Law:
F = kq₁q₂/r²
Where k = 9 × 10⁹ Nm²/C² (in vacuum)
k = 1/(4πε₀), ε₀ = 8.85 × 10^-12 C²/Nm²

Electric Field:
E = F/q = kQ/r²
Direction: Away from +ve, towards -ve charge
Unit: N/C or V/m

Electric Potential:
V = W/q = kQ/r
Unit: Volt (V), 1 V = 1 J/C

Relation:
E = -dV/dr
V = -∫E·dr

Potential Energy:
U = qV = kq₁q₂/r

2. Gauss's Law

Statement:
Electric flux through closed surface = Charge enclosed/ε₀
Φ = ∮E·dA = q/ε₀

Applications:
• Infinite line charge: E = λ/(2πε₀r)
• Infinite sheet: E = σ/(2ε₀)
• Spherical shell (outside): E = kQ/r²
• Spherical shell (inside): E = 0
• Solid sphere (outside): E = kQ/r²
• Solid sphere (inside): E = kQr/R³

3. Capacitance

Definition:
C = Q/V
Unit: Farad (F), 1 F = 1 C/V

Parallel Plate Capacitor:
C = ε₀A/d (without dielectric)
C = Kε₀A/d (with dielectric, K = dielectric constant)

Energy Stored:
U = (1/2)QV = (1/2)CV² = Q²/(2C)

Series Combination:
1/C = 1/C₁ + 1/C₂ + 1/C₃

Parallel Combination:
C = C₁ + C₂ + C₃

🔍 Numerical 8: Two charges +2μC and -3μC are 10 cm apart. Find force between them.

Given: q₁ = 2 × 10^-6 C, q₂ = -3 × 10^-6 C, r = 0.1 m

Using F = kq₁q₂/r²
F = (9 × 10⁹) × (2 × 10^-6) × (3 × 10^-6) / (0.1)²
F = (9 × 10⁹) × (6 × 10^-12) / 0.01
F = 54 × 10^-3 / 0.01
F = 5.4 N (attractive force)

Answer: Force = 5.4 N (attraction)

⚠️ Common Mistake:

Students forget to convert units! μC to C, cm to m before substituting. Also, negative charges attract, positive repel - don't confuse directions!

🧪 CHEMISTRY - COMPLETE COVERAGE

Organic, Inorganic, Physical Chemistry with reactions and mechanisms

⚛️ Atomic Structure & Periodic Table

1. Atomic Models

• Dalton's Model: Atom is indivisible particle
• Thomson's Model: Plum pudding model - electrons in positive sphere
• Rutherford's Model: Nucleus at center, electrons revolve around
• Bohr's Model: Electrons in fixed orbits with quantized energy

Bohr's Theory:
Energy of nth orbit: E(n) = -13.6/n² eV
Radius of nth orbit: r(n) = 0.529n² Å

Energy of photon emitted:
ΔE = 13.6(1/n₁² - 1/n₂²) eV
E = hν = hc/λ

Where: h = Planck's constant = 6.626 × 10^-34 Js
c = speed of light = 3 × 10⁸ m/s

2. Electronic Configuration

Quantum Numbers:
• Principal (n): Shell number (1, 2, 3...)
• Azimuthal (l): Subshell (0=s, 1=p, 2=d, 3=f)
• Magnetic (m): Orbital orientation (-l to +l)
• Spin (s): +1/2 or -1/2

Aufbau Principle: Fill lower energy orbitals first
Order: 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p...

Pauli Exclusion: No two electrons with same 4 quantum numbers

Hund's Rule: Maximum unpaired electrons in degenerate orbitals

3. Periodic Properties

Periodic Trends:

Atomic Radius:
• Decreases → across period (left to right)
• Increases ↓ down group

Ionization Energy:
• Increases → across period
• Decreases ↓ down group

Electron Affinity:
• Generally increases → across period
• Decreases ↓ down group

Electronegativity:
• Increases → across period
• Decreases ↓ down group
Most electronegative: F (4.0)
Least electronegative: Cs (0.7)

💡 Memory Trick - Electronic Config:

"Silly People Drink Fizzy drinks" = s, p, d, f subshells. Maximum electrons: s=2, p=6, d=10, f=14. Remember 2-6-10-14!

🔗 Chemical Bonding

1. Types of Bonds

• Ionic Bond: Transfer of electrons (metal + non-metal). Example: NaCl, MgO
• Covalent Bond: Sharing of electrons (non-metal + non-metal). Example: H₂, O₂, CH₄
• Coordinate Bond: Both electrons from same atom. Example: NH₃→BF₃
• Metallic Bond: Sea of electrons. Example: Fe, Cu, Al
• Hydrogen Bond: Between H and F/O/N. Example: H₂O, HF

2. VSEPR Theory

Electron Pairs	Shape	Bond Angle	Example
2 BP	Linear	180°	BeCl₂, CO₂
3 BP	Trigonal planar	120°	BF₃
2 BP + 1 LP	Bent	<120°	SO₂
4 BP	Tetrahedral	109.5°	CH₄, CCl₄
3 BP + 1 LP	Pyramidal	107°	NH₃
2 BP + 2 LP	Bent	104.5°	H₂O
5 BP	Trigonal bipyramidal	90°, 120°	PCl₅
6 BP	Octahedral	90°	SF₆

BP = Bond Pair, LP = Lone Pair

3. Hybridization

Types:
• sp: Linear (180°) - BeCl₂
• sp²: Trigonal planar (120°) - BF₃, C₂H₄
• sp³: Tetrahedral (109.5°) - CH₄, NH₃, H₂O
• sp³d: Trigonal bipyramidal (90°, 120°) - PCl₅
• sp³d²: Octahedral (90°) - SF₆

Determining Hybridization:
Number of hybrid orbitals = Bond pairs + Lone pairs

Example: NH₃
3 bond pairs + 1 lone pair = 4 orbitals = sp³

⚠️ Common Mistake:

Students confuse shape with geometry! CH₄ is tetrahedral, NH₃ is pyramidal, H₂O is bent - all have sp³ hybridization but different shapes due to lone pairs!

⚗️ Chemical Reactions & Equations

1. Types of Reactions

• Combination: A + B → AB (Example: 2H₂ + O₂ → 2H₂O)
• Decomposition: AB → A + B (Example: 2H₂O → 2H₂ + O₂)
• Displacement: A + BC → AC + B (Example: Zn + CuSO₄ → ZnSO₄ + Cu)
• Double Displacement: AB + CD → AD + CB (Example: NaCl + AgNO₃ → AgCl + NaNO₃)
• Redox: Oxidation + Reduction (Example: CuO + H₂ → Cu + H₂O)

2. Balancing Equations

🔍 Example: Balance Fe + H₂O → Fe₃O₄ + H₂

Step 1: Count atoms on both sides
Left: Fe=1, H=2, O=1
Right: Fe=3, O=4, H=2

Step 2: Balance Fe (multiply Fe by 3)
3Fe + H₂O → Fe₃O₄ + H₂

Step 3: Balance O (multiply H₂O by 4)
3Fe + 4H₂O → Fe₃O₄ + H₂

Step 4: Balance H (multiply H₂ by 4)
3Fe + 4H₂O → Fe₃O₄ + 4H₂ ✓

Balanced Equation: 3Fe + 4H₂O → Fe₃O₄ + 4H₂

3. Mole Concept

Key Definitions:
1 mole = 6.022 × 10²³ particles (Avogadro's number)
1 mole gas = 22.4 L at STP

Formulas:
Number of moles (n) = Mass/Molar mass = m/M
n = Volume/22.4 (at STP)
n = Number of particles/Avogadro's number

Molarity:
M = Moles of solute/Volume of solution (L)

Percentage Composition:
% of element = (Mass of element/Molecular mass) × 100

🔍 Numerical 9: Find moles in 18 g water (H₂O).

Molar mass of H₂O = 2(1) + 16 = 18 g/mol

Number of moles = Mass/Molar mass
n = 18/18 = 1 mole

Number of molecules = n × N(A)
= 1 × 6.022 × 10²³
= 6.022 × 10²³ molecules

Answer: 1 mole = 6.022 × 10²³ molecules

🔥 Balancing Equations - Most Important!

Practice 50+ equations! Boards always have 3-4 marks on balancing. Master redox equations especially. Easy marks if you practice!

🌊 Acids, Bases & Salts

1. Acid-Base Theories

• Arrhenius Theory:
  Acid: Gives H⁺ in water (HCl → H⁺ + Cl⁻)
  Base: Gives OH⁻ in water (NaOH → Na⁺ + OH⁻)
• Bronsted-Lowry Theory:
  Acid: Proton (H⁺) donor
  Base: Proton (H⁺) acceptor
• Lewis Theory:
  Acid: Electron pair acceptor
  Base: Electron pair donor

2. pH Scale

pH Definition:
pH = -log[H⁺]
pOH = -log[OH⁻]
pH + pOH = 14 (at 25°C)

pH Scale:
pH < 7 = Acidic
pH = 7 = Neutral
pH > 7 = Basic/Alkaline

Relation:
[H⁺][OH⁻] = 10^-14 (K(w) = ionic product of water)

Buffer Solutions:
Resist pH change on adding acid/base
Example: CH₃COOH + CH₃COONa (acidic buffer)
NH₄OH + NH₄Cl (basic buffer)

3. Important Reactions

Neutralization:
Acid + Base → Salt + Water
HCl + NaOH → NaCl + H₂O

Acid + Metal:
2HCl + Zn → ZnCl₂ + H₂↑

Acid + Metal Carbonate:
2HCl + Na₂CO₃ → 2NaCl + H₂O + CO₂↑

Base + Ammonium Salt:
NaOH + NH₄Cl → NaCl + NH₃↑ + H₂O

💡 Memory Trick - pH:

"pH" = "Power of Hydrogen". Lower pH = More H⁺ = More acidic. Remember: Lemon (pH 2) < Vinegar (pH 3) < Coffee (pH 5) < Pure water (pH 7) < Baking soda (pH 9) < Soap (pH 10)

🧬 BIOLOGY - COMPLETE COVERAGE

Cell structure, genetics, human body systems, ecology, evolution

🔬 Cell Biology

1. Cell Structure

• Cell Membrane: Selectively permeable, made of lipid bilayer with proteins
• Cytoplasm: Jelly-like substance, site of cellular activities
• Nucleus: Control center, contains DNA, surrounded by nuclear membrane
• Mitochondria: Powerhouse of cell, ATP production (cellular respiration)
• Ribosomes: Protein synthesis (found on ER or free in cytoplasm)
• Endoplasmic Reticulum (ER):
  • Rough ER: Has ribosomes, protein synthesis
  • Smooth ER: No ribosomes, lipid synthesis
• Golgi Apparatus: Packaging and dispatch of materials
• Lysosomes: Digestive bags, waste disposal
• Chloroplasts: Photosynthesis (only in plant cells)
• Vacuoles: Storage (large in plant cells, small in animal cells)
• Cell Wall: Rigid outer layer (only in plant cells, made of cellulose)

2. Cell Division

Mitosis (Somatic cells):
Purpose: Growth, repair, asexual reproduction
Phases: Prophase → Metaphase → Anaphase → Telophase
Result: 2 daughter cells with same chromosome number (diploid 2n)

Meiosis (Gamete formation):
Purpose: Sexual reproduction
Two divisions: Meiosis I and Meiosis II
Result: 4 daughter cells with half chromosome number (haploid n)

Key Differences:
Mitosis: 2n → 2n (diploid remains)
Meiosis: 2n → n (diploid to haploid)

3. Cell Processes

Diffusion: Movement from high to low concentration

Osmosis: Movement of water through semipermeable membrane
• Hypotonic solution: Cell swells (water enters)
• Hypertonic solution: Cell shrinks (water leaves)
• Isotonic solution: No net movement

Active Transport: Movement against concentration gradient (requires energy/ATP)

💡 Memory Trick - Mitosis Phases:

"PMAT" = Prophase, Metaphase, Anaphase, Telophase. Or remember: "Please Make Another Test" for sequence!

🧬 Genetics & Heredity

1. Mendelian Genetics

Key Terms:
• Gene: Unit of heredity
• Allele: Alternative forms of gene
• Dominant: Expressed in heterozygous (represented by capital letter T)
• Recessive: Expressed only in homozygous (small letter t)
• Genotype: Genetic makeup (TT, Tt, tt)
• Phenotype: Physical appearance (Tall, Short)
• Homozygous: Same alleles (TT or tt)
• Heterozygous: Different alleles (Tt)

Mendel's Laws:
1. Law of Dominance: Dominant trait expressed in F₁
2. Law of Segregation: Alleles separate during gamete formation
3. Law of Independent Assortment: Genes for different traits assort independently

2. Monohybrid Cross

🔍 Example: Cross between Tall (TT) and Short (tt) pea plants

P generation: TT (Tall) × tt (Short)
Gametes: T and t
F₁ generation: All Tt (Tall) - 100% Tall

F₁ × F₁: Tt × Tt
Gametes: T, t from each parent

F₂ generation:
TT : Tt : Tt : tt
1 : 2 : 1 (Genotypic ratio)

Tall : Short = 3 : 1 (Phenotypic ratio)

Result: 75% Tall, 25% Short

3. DNA & RNA

DNA (Deoxyribonucleic Acid):
Structure: Double helix (Watson & Crick model)
Components: Deoxyribose sugar + Phosphate + Nitrogenous bases
Bases: Adenine (A), Thymine (T), Guanine (G), Cytosine (C)
Base pairing: A=T (2 bonds), G≡C (3 bonds)
Location: Nucleus
Function: Genetic information storage

RNA (Ribonucleic Acid):
Structure: Single strand
Components: Ribose sugar + Phosphate + Bases
Bases: Adenine, Uracil (U), Guanine, Cytosine
Types: mRNA, tRNA, rRNA
Function: Protein synthesis

4. Protein Synthesis

• Transcription: DNA → mRNA (in nucleus)
• Translation: mRNA → Protein (at ribosomes)
• Genetic Code: Triplet codon (3 bases) codes for 1 amino acid
• Mutations: Changes in DNA sequence

🔥 Genetics = 10-12 marks in boards!

Practice Punnett squares thoroughly! Monohybrid and dihybrid crosses are favorite questions. Draw clear diagrams. Easy full marks if you practice!

❤️ Human Body Systems

1. Digestive System

• Mouth: Salivary amylase breaks starch → maltose
• Esophagus: Peristalsis moves food to stomach
• Stomach: HCl + Pepsin digests proteins. Gastric juice secreted
• Small Intestine:
  • Duodenum: Pancreatic juice (trypsin, lipase, amylase)
  • Bile from liver emulsifies fats
  • Intestinal juice completes digestion
  • Villi absorb nutrients
• Large Intestine: Water absorption, undigested food stored
• Anus: Egestion of feces

2. Respiratory System

Pathway:
Nostrils → Nasal cavity → Pharynx → Larynx → Trachea → Bronchi → Bronchioles → Alveoli

Gas Exchange (at alveoli):
O₂ diffuses from alveoli → blood capillaries
CO₂ diffuses from blood → alveoli

Breathing Mechanism:
Inhalation: Diaphragm contracts, moves down, lungs expand
Exhalation: Diaphragm relaxes, moves up, lungs contract

Respiration Equation:
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy (ATP)

3. Circulatory System

• Heart: 4 chambers (2 atria + 2 ventricles), pumps blood
• Blood Vessels:
  • Arteries: Carry oxygenated blood away from heart (except pulmonary artery)
  • Veins: Carry deoxygenated blood to heart (except pulmonary vein)
  • Capillaries: Exchange of materials
• Blood Components:
  • Plasma: Liquid part (90% water)
  • RBC: Carry oxygen (hemoglobin)
  • WBC: Fight infection (immunity)
  • Platelets: Blood clotting

4. Excretory System

• Kidneys: Filter blood, form urine (nephron = functional unit)
• Ureters: Carry urine from kidneys to bladder
• Urinary Bladder: Stores urine
• Urethra: Urine expelled

Nephron Functions:
1. Filtration: Blood filtered in glomerulus
2. Reabsorption: Useful substances reabsorbed in tubules
3. Secretion: Waste substances secreted into urine

Urine Composition: 95% water, 2.5% urea, 2.5% other wastes

5. Nervous System

• Central Nervous System (CNS): Brain + Spinal cord
• Peripheral Nervous System (PNS): All nerves outside CNS
• Neuron: Functional unit (Dendrite → Cell body → Axon)
• Synapse: Gap between two neurons
• Reflex Arc: Receptor → Sensory neuron → Spinal cord → Motor neuron → Effector (quick automatic response)

⚠️ Diagram Alert!

Human heart, nephron, neuron, digestive system diagrams are must-practice! Label all parts clearly. 3-5 marks guaranteed in every exam!

🌱 Plant Biology

1. Photosynthesis

Equation:
6CO₂ + 6H₂O + Light energy → C₆H₁₂O₆ + 6O₂
(Chlorophyll)

Site: Chloroplasts (in mesophyll cells of leaves)

Process:
Light Reaction: Light absorbed, water split, O₂ released, ATP & NADPH formed
Dark Reaction (Calvin Cycle): CO₂ fixed, glucose formed using ATP & NADPH

Factors Affecting:
• Light intensity
• CO₂ concentration
• Temperature
• Water availability
• Chlorophyll content

2. Plant Transport

• Xylem: Transport water & minerals (roots → leaves)
  Mechanism: Transpiration pull, root pressure, capillary action
• Phloem: Transport food (leaves → all parts)
  Mechanism: Translocation (pressure flow)
• Stomata: Pores on leaf for gas exchange
  Guard cells control opening/closing

3. Plant Hormones

• Auxins: Cell elongation, phototropism, apical dominance
• Gibberellins: Stem growth, seed germination
• Cytokinins: Cell division, delay aging
• Abscisic Acid: Stomatal closure, seed dormancy (stress hormone)
• Ethylene: Fruit ripening

4. Plant Reproduction

• Asexual: Vegetative propagation (cutting, layering, grafting, budding)
• Sexual: Flowers (male = stamen, female = pistil)
  Process: Pollination → Fertilization → Seed formation → Germination

💡 Memory Trick - Photosynthesis:

"6-6-1-6" equation! 6 CO₂ + 6 H₂O → 1 C₆H₁₂O₆ + 6 O₂. Remember this number pattern!

📋 PRACTICALS & VIVA QUESTIONS

Important experiments, diagrams, and common viva questions with answers

🔬 Physics Practicals

1. Ohm's Law Verification

Aim: To verify Ohm's law (V = IR)

Apparatus: Battery, ammeter, voltmeter, resistor, rheostat, key, connecting wires

Procedure:

• Connect circuit: Battery → Key → Rheostat → Resistor → Ammeter → Battery
• Connect voltmeter parallel to resistor
• Close key, adjust rheostat, note V and I
• Repeat for different values, calculate V/I

Observation: V/I = constant = R (Ohm's law verified)

2. Focal Length of Concave Mirror

Aim: Find focal length using u-v method

Formula: 1/f = 1/v + 1/u

Procedure: Place object at different distances, measure image distance, calculate f

Common Viva Questions - Physics

• Q: Why is ammeter connected in series?
  A: To measure total current flowing through circuit. In series, same current flows.
• Q: Why is voltmeter connected in parallel?
  A: To measure potential difference across component. Same voltage in parallel.
• Q: What is least count?
  A: Smallest measurement possible with instrument. For scale: 1 mm, vernier: 0.1 mm
• Q: Why do we use thick copper wire in circuits?
  A: Low resistance, good conductor, prevents heating.
• Q: Real vs Virtual image?
  A: Real = can be obtained on screen (inverted). Virtual = cannot be on screen (erect).

⚗️ Chemistry Practicals

1. pH Determination

Aim: Find pH using indicators or pH paper

Indicators:

• Litmus: Red in acid, Blue in base
• Phenolphthalein: Colorless in acid, Pink in base
• Methyl orange: Red in acid, Yellow in base

2. Salt Analysis

Tests for Cations:

• Pb²⁺: White ppt with dilute HCl
• Cu²⁺: Blue color in solution, blue ppt with NH₄OH
• Fe²⁺: Dirty green ppt with NH₄OH
• Fe³⁺: Reddish brown ppt with NH₄OH
• Zn²⁺: White ppt with NH₄OH, soluble in excess

Tests for Anions:

• Cl⁻: White ppt with AgNO₃
• SO₄²⁻: White ppt with BaCl₂
• CO₃²⁻: Effervescence with dilute acid, CO₂ turns lime water milky
• NO₃⁻: Brown ring test with FeSO₄ + H₂SO₄

Common Viva Questions - Chemistry

• Q: Why do we add dilute HCl before group analysis?
  A: To precipitate Group 1 cations (Pb²⁺, Ag⁺, Hg₂²⁺) as chlorides.
• Q: What is brown ring test?
  A: Test for NO₃⁻. Brown ring forms at junction of FeSO₄ and H₂SO₄ layers.
• Q: Why is conc. H₂SO₄ not used for preparing HCl gas?
  A: It is non-volatile and will contaminate HCl gas.
• Q: Difference between precipitate and residue?
  A: Precipitate = solid formed in solution. Residue = solid left after filtration.
• Q: What is universal indicator?
  A: Mixture of indicators showing different colors at different pH (1-14 scale).

🔬 Biology Practicals

1. Starch Test in Leaves

Aim: Test for presence of starch (photosynthesis)

Procedure:

• Boil leaf in water (kill cells, soften)
• Boil in alcohol (remove chlorophyll)
• Wash and add iodine solution
• Blue-black color = starch present

2. Temporary Mount Slides

Onion Peel: Shows cell wall, nucleus, cytoplasm clearly

Human Cheek Cells: Shows cell membrane, nucleus, cytoplasm (no cell wall)

Stomata: Observe guard cells, stomatal pore in leaf epidermis

3. Seed Germination Experiment

Variables tested: Water, air, temperature, light

Conclusion: Water, air, suitable temperature needed. Light not essential for germination.

Common Viva Questions - Biology

• Q: Why boil leaf in alcohol?
  A: To remove chlorophyll so iodine color is clearly visible.
• Q: Why do we use safranin/methylene blue stain?
  A: To make cell parts visible under microscope by coloring them.
• Q: Difference between plant and animal cell?
  A: Plant has cell wall, large vacuole, chloroplasts. Animal has centrioles, small vacuoles.
• Q: What is the function of glycerine in mounting?
  A: Prevents drying of specimen, maintains for longer observation.
• Q: Why is iodine used for starch test?
  A: Iodine forms blue-black complex with starch specifically.
• Q: What is plasmolysis?
  A: Shrinking of cytoplasm from cell wall when placed in hypertonic solution.

🔥 Practical Exam Strategy!

Draw neat labeled diagrams! Clean observations! Write precautions. Know all apparatus names. Practice viva answers loudly. Confidence matters! Practicals = 30 marks, don't ignore!

🔗 More Science Resources

Explore additional resources for deeper understanding of science concepts

About Us 📊 Question Bank Info Library Science Blogs

Advertisement