| name | biology |
| description | CBSE Grade 10 Biology — Life Processes, Control & Coordination, Reproduction, Heredity, Environment. Activate for biology concepts, diagrams, processes, and board exam preparation. |
Biology — CBSE Grade 10 Science
Syllabus Coverage (2026–27)
| Unit | Chapters | Marks |
|---|
| II. World of Living | Ch 5: Life Processes | 25 |
| Ch 6: Control and Coordination | (combined) |
| Ch 7: How do Organisms Reproduce? | |
| Ch 8: Heredity | |
| V. Natural Resources | Ch 13: Our Environment | 5 |
| Biology Total | 5 Chapters | ~30 |
Chapter 5: Life Processes
Key Concepts
Nutrition:
- Autotrophic nutrition (Photosynthesis):
- 6CO₂ + 6H₂O →sunlight, chlorophyll→ C₆H₁₂O₆ + 6O₂
- Steps: Light reaction → Dark reaction (Calvin cycle)
- Raw materials: CO₂ (from stomata), H₂O (from roots), Sunlight, Chlorophyll
- Heterotrophic nutrition: Holozoic, Saprophytic, Parasitic
- Human Digestive System (DIAGRAM MUST):
- Mouth → Oesophagus → Stomach → Small intestine → Large intestine → Anus
- Salivary amylase (starch → maltose, pH ~6.8)
- Pepsin (proteins → peptones, pH ~2, HCl in stomach)
- Bile (emulsification of fats, from liver)
- Pancreatic enzymes: trypsin (proteins), lipase (fats), amylase (starch)
- Villi in small intestine → absorption (large surface area)
Respiration:
- Aerobic: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + 38 ATP (mitochondria)
- Anaerobic (yeast): C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂ + 2 ATP
- Anaerobic (muscles): C₆H₁₂O₆ → 2C₃H₆O₃ (lactic acid) + 2 ATP
- Human Respiratory System (DIAGRAM MUST):
- Nostrils → Nasal cavity → Pharynx → Larynx → Trachea → Bronchi → Bronchioles → Alveoli
- Alveoli: thin walls, rich blood supply, large surface area → gas exchange
Transportation:
- Human Heart (DIAGRAM MUST — 4 chambers):
- Right atrium → Right ventricle → Pulmonary artery → Lungs
- Lungs → Pulmonary vein → Left atrium → Left ventricle → Aorta → Body
- Double circulation: pulmonary + systemic
- Valves prevent backward flow
- Blood: RBCs (carry O₂), WBCs (fight infection), Platelets (clotting), Plasma (liquid)
- Blood vessels: Arteries (thick walls, high pressure), Veins (valves, low pressure), Capillaries (thin walls, exchange)
- Transportation in plants:
- Xylem: water + minerals (upward) — transpiration pull, root pressure
- Phloem: food (sugars) — translocation (bidirectional, uses ATP)
Excretion:
- Human Excretory System (DIAGRAM MUST):
- Kidneys → Ureters → Urinary bladder → Urethra
- Nephron (functional unit, DIAGRAM MUST):
- Bowman's capsule → Proximal tubule → Loop of Henle → Distal tubule → Collecting duct
- Filtration → Reabsorption → Secretion → Urine
- Urine composition: water, urea, uric acid, salts
- Excretion in plants: O₂ (day), CO₂ (night), excess water (transpiration), resins/gums stored in old xylem
Diagram Checklist (Board Exam)
Chapter 6: Control and Coordination
Key Concepts
Nervous System:
- Neuron (DIAGRAM MUST): Cell body → Dendrite → Axon → Axon terminal → Synapse
- Reflex arc: Receptor → Sensory nerve → Spinal cord → Motor nerve → Effector
- Types: Voluntary (cerebrum), Involuntary (medulla), Reflex (spinal cord)
- Human Brain (DIAGRAM MUST):
- Cerebrum: thinking, memory, sensation
- Cerebellum: balance, posture
- Medulla oblongata: breathing, heartbeat, blood pressure
- Pons: relay between cerebrum and cerebellum
Hormonal System (Endocrine Glands):
| Gland | Hormone | Function |
|---|
| Pituitary | Growth hormone | Growth of bones and muscles |
| Thyroid | Thyroxine | Metabolism (needs iodine) |
| Pancreas | Insulin | Lowers blood sugar (diabetes if deficient) |
| Pancreas | Glucagon | Raises blood sugar |
| Adrenal | Adrenaline | Fight-or-flight response |
| Testes | Testosterone | Male secondary sexual characters |
| Ovaries | Estrogen | Female secondary sexual characters |
Plant Hormones:
| Hormone | Function |
|---|
| Auxin | Cell elongation, phototropism, gravitropism |
| Gibberellin | Stem elongation, seed germination |
| Cytokinin | Cell division, delays aging |
| Abscisic acid | Growth inhibitor, wilting, dormancy |
| Ethylene | Fruit ripening |
Tropic Movements in Plants:
- Phototropism: response to light (shoots +ve, roots -ve)
- Geotropism: response to gravity (roots +ve, shoots -ve)
- Hydrotropism: response to water (roots +ve)
- Chemotropism: response to chemicals (pollen tube towards ovule)
- Thigmotropism: response to touch (tendrils)
Chapter 7: How do Organisms Reproduce?
Key Concepts
Asexual Reproduction:
- Fission: Binary (Amoeba), Multiple (Plasmodium)
- Budding: Hydra, Yeast
- Spore formation: Rhizopus
- Fragmentation: Spirogyra
- Regeneration: Planaria
- Vegetative propagation: runners (grass), tubers (potato), bulbs (onion), grafting, layering, cutting
Sexual Reproduction in Flowering Plants:
- Flower structure (DIAGRAM MUST):
- Sepals (calyx) → Petals (corolla) → Stamens (androecium: anther + filament) → Pistil (gynoecium: stigma + style + ovary)
- Pollination: Self-pollination vs Cross-pollination
- Fertilization: Pollen grain → Pollen tube → Ovule → Fusion of gametes
- Post-fertilization: Ovule → Seed, Ovary → Fruit
Sexual Reproduction in Humans:
- Male reproductive system (DIAGRAM): Testes → Vas deferens → Seminal vesicles → Prostate → Urethra → Penis
- Female reproductive system (DIAGRAM): Ovaries → Fallopian tubes → Uterus → Vagina
- Fertilization occurs in fallopian tube
- Implantation in uterus wall
- Placenta: provides nutrition, O₂ to embryo; removes wastes
- Menstruation: 28-day cycle; uterine lining sheds if no fertilization
Contraception Methods:
- Barrier: Condom, diaphragm
- Chemical: Oral pills (hormonal)
- Intrauterine device: Copper-T
- Surgical: Vasectomy (male), Tubectomy (female)
Chapter 8: Heredity
Key Concepts
- Genetics: study of inheritance
- Gene: unit of inheritance, part of DNA on chromosome
- Alleles: different forms of a gene (dominant T, recessive t)
- Mendel's Laws:
- Law of Dominance: dominant allele expresses in F₁
- Law of Segregation: alleles separate during gamete formation
- Law of Independent Assortment: genes on different chromosomes sort independently
Mendel's Cross (MUST know)
MONOHYBRID CROSS (one trait):
Parents: TT (tall) × tt (short)
F₁: Tt (all tall) — dominant trait expressed
F₁ × F₁: Tt × Tt
F₂: TT : Tt : Tt : tt = 3 Tall : 1 Short
Genotypic ratio: 1:2:1
Phenotypic ratio: 3:1
DIHYBRID CROSS (two traits):
Parents: RRYY × rryy
F₁: RrYy (all round yellow)
F₁ × F₁: RrYy × RrYy
F₂ Phenotypic ratio: 9:3:3:1
9 Round Yellow : 3 Round Green : 3 Wrinkled Yellow : 1 Wrinkled Green
Sex Determination
Humans: XX-XY system
Female: XX (homogametic)
Male: XY (heterogametic)
Father determines sex of child:
X sperm + X egg → XX (girl)
Y sperm + X egg → XY (boy)
Probability: 50% boy, 50% girl
Evolution Concepts
- Acquired characters are NOT inherited (Lamarck was wrong)
- Natural selection: organisms best adapted survive (Darwin)
- Homologous organs: same structure, different function (human hand, whale flipper, bat wing)
- Analogous organs: different structure, same function (bird wing, insect wing)
- Fossils: preserved remains, evidence of evolution
- Speciation: geographical isolation → genetic drift → new species
Chapter 13: Our Environment
Key Concepts
- Ecosystem: biotic + abiotic components interacting
- Food chain: Grass → Grasshopper → Frog → Snake → Hawk
- Food web: interconnected food chains
- Trophic levels: Producers (T1) → Primary consumers (T2) → Secondary consumers (T3) → Tertiary consumers (T4)
- 10% Law: Only 10% energy transfers to next trophic level
- Biological magnification: concentration of toxins increases at higher trophic levels
- Ozone layer: O₃ in stratosphere, protects from UV; depleted by CFCs
- Biodegradable waste: broken down by microorganisms (paper, food waste)
- Non-biodegradable waste: NOT broken down (plastic, glass, metal)
Key Formulas
10% LAW:
If producers have 10,000 J energy:
T1 (Producers): 10,000 J
T2 (Herbivores): 1,000 J
T3 (Carnivores): 100 J
T4 (Top carnivores): 10 J
OZONE FORMATION:
O₂ →UV→ O + O (dissociation)
O + O₂ → O₃ (ozone formation)
OZONE DEPLETION:
CFCs →UV→ Cl + other fragments
Cl + O₃ → ClO + O₂
ClO + O₃ → Cl + 2O₂ (Cl acts as catalyst)
High-Yield Topics (495+ Strategy)
- Life Processes (Digestion, Heart, Nephron) — 5M diagram-based LA guaranteed
- Heredity (Mendel's crosses) — 3-5M cross problems
- Reproduction — 3-5M flower structure / human reproductive system
- Control and Coordination — 3M hormones table, reflex arc
- Environment — 2-3M food chain / 10% law
Common Mistakes to Avoid
- Not drawing diagrams neatly with ALL labels
- Confusing xylem (water, dead cells, upward) with phloem (food, living cells, bidirectional)
- Mixing up arteries (away from heart) and veins (towards heart)
- Wrong genotypic vs phenotypic ratios
- Forgetting that father determines sex (not mother)
- Not mentioning "10% law" by name in energy flow questions
Answer Writing Framework for Biology
- Diagrams = marks: Draw first, then explain. Label every part.
- Use biological terms: "peristalsis" not "pushing food", "transpiration" not "water loss"
- For process questions: Write steps in numbered sequence
- For comparison: Use a table format (Arteries vs Veins, Xylem vs Phloem)
- Mendel crosses: Always draw the cross diagram with Punnett square
- Define, then explain: Start with definition, then elaborate
Internal Assessment Notes
| Component | Details |
|---|
| Practical Exam | Experiments: stomata observation, CO₂ in exhaled air, germination, plant & animal specimens |
| Practical viva | Focus on Life Processes and Reproduction experiments |
| Projects | Biodiversity, pollution, genetics project — present neatly with diagrams |
