NCERT Class 10 Life Processes: Complete Chapter Notes
Life Processes is Chapter 6 in NCERT Class 10 Science and one of the highest-weightage chapters in the CBSE Board Exam. It covers the fundamental biological processes essential for sustaining life — Nutrition, Respiration, Transportation, and Excretion — in plants, animals, and microorganisms.
This guide provides complete NCERT Class 10 Life Processes notes with definitions, diagrams description, process explanations, comparison tables, and a practice MCQ quiz for CBSE Board 2026.
What are Life Processes?
Life processes are those processes which are necessary for the maintenance of life in living organisms. The main life processes include:
| Life Process | Definition | Organ/Structure |
|---|---|---|
| Nutrition | Obtaining and using food for energy and growth | Digestive system, chloroplasts |
| Respiration | Breakdown of food to release energy | Mitochondria, lungs |
| Transportation | Circulation of nutrients, gases, and waste | Blood, xylem, phloem |
| Excretion | Removal of metabolic waste products | Kidneys, stomata, skin |
Nutrition in Plants: Photosynthesis
Photosynthesis equation:
6CO₂ + 6H₂O + Sunlight → C₆H₁₂O₆ (Glucose) + 6O₂
| Condition Required | Role |
|---|---|
| Chlorophyll (green pigment) | Absorbs sunlight; light energy trapped here |
| Sunlight | Energy source for splitting water molecules |
| Carbon Dioxide (CO₂) | Raw material; enters through stomata |
| Water (H₂O) | Raw material; absorbed by roots, transported by xylem |
Nutrition in Animals: Human Digestive System
| Organ | Function | Enzyme/Juice Secreted |
|---|---|---|
| Mouth | Mechanical digestion + starch digestion | Salivary amylase (breaks starch) |
| Oesophagus | Passes food to stomach (peristalsis) | None |
| Stomach | Protein digestion; kills bacteria | Pepsin + HCl (gastric juice) |
| Small Intestine | Complete digestion + absorption of nutrients | Pancreatic juice, bile, intestinal juice |
| Large Intestine | Water absorption; forms faeces | None |
| Liver | Produces bile (emulsifies fats) | Bile |
| Pancreas | Produces enzymes for all food types | Amylase, lipase, trypsin |
Respiration: Types Comparison
| Feature | Aerobic Respiration | Anaerobic Respiration |
|---|---|---|
| Oxygen required? | Yes | No |
| Products | CO₂ + H₂O + Energy | Lactic acid (muscles) OR CO₂ + Alcohol (yeast) |
| Energy released | High (38 ATP) | Low (2 ATP) |
| Location | Mitochondria | Cytoplasm |
| Organisms | Most plants and animals | Yeast, bacteria, muscle cells (during exercise) |
Transportation in Humans: Blood Circulatory System
| Component | Function |
|---|---|
| Heart | Pumps blood; 4 chambers (2 atria + 2 ventricles); double circulation |
| Arteries | Carry blood from heart; thick walls; high pressure; usually oxygenated |
| Veins | Carry blood to heart; thin walls; low pressure; valves to prevent backflow |
| Capillaries | Thin-walled; site of exchange of nutrients, gases, waste |
| Red Blood Cells | Contain haemoglobin; carry oxygen |
| White Blood Cells | Immunity; fight pathogens |
| Platelets | Blood clotting |
| Plasma | Liquid; transports dissolved food, CO₂, hormones, waste |
Transportation in Plants: Xylem and Phloem
| Feature | Xylem | Phloem |
|---|---|---|
| What it transports | Water and minerals | Food (sucrose, amino acids) |
| Direction | Unidirectional (roots → leaves) | Bidirectional (leaves → all parts) |
| Force | Transpiration pull + root pressure | Active transport (energy needed) |
| Cells | Tracheids + Vessels (dead cells) | Sieve tubes + companion cells (living) |
Excretion in Humans: Nephron and Kidney Function
The nephron is the functional unit of the kidney. Each kidney has approximately 1 million nephrons.
Steps of urine formation:
- Ultrafiltration: Blood filtered in Bowman’s capsule — glucose, urea, water, salts enter the tubule
- Selective Reabsorption: Glucose, amino acids, useful salts, most water reabsorbed back into blood
- Tubular Secretion: Additional waste (H⁺ ions, K⁺) secreted into the filtrate
- Urine formed: Contains urea, excess salts, water — passed to ureter → bladder → urethra
Excretion in Plants
| Waste Product | Elimination Method |
|---|---|
| CO₂ (respiration) | Released through stomata/lenticels |
| O₂ (photosynthesis) | Released through stomata |
| Excess water | Transpiration through stomata |
| Resinous waste | Stored in bark or heartwood |
| Tannins, latex, gums | Stored in vacuoles or bark cells |
Practice Quiz: NCERT Class 10 Life Processes
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Frequently Asked Questions: Class 10 Life Processes
What are the main life processes in Class 10 NCERT?
The main life processes covered in NCERT Class 10 Chapter 6 are: Nutrition (obtaining food — autotrophic like photosynthesis and heterotrophic like digestion), Respiration (aerobic and anaerobic — releasing energy from food), Transportation (circulatory system in animals; xylem and phloem in plants), and Excretion (removal of metabolic waste — kidneys in humans, stomata in plants).
What is the difference between aerobic and anaerobic respiration?
Aerobic respiration uses oxygen to completely break down glucose into CO₂ and water, releasing 38 ATP of energy. It occurs in mitochondria. Anaerobic respiration occurs without oxygen — in muscles it produces lactic acid (causing cramps), and in yeast it produces CO₂ and ethanol (alcohol). Anaerobic respiration produces only 2 ATP — much less energy than aerobic.
How many marks does Life Processes carry in CBSE Class 10 Board Exam?
Life Processes (Chapter 6) is one of the highest-scoring chapters in CBSE Class 10 Science. It typically carries 7–10 marks in the board exam (out of 80 marks for theory). Questions come from all four topics: Nutrition, Respiration, Transportation, and Excretion. Diagram-based questions (nephron, heart, digestive system, leaf cross-section) are frequently asked for 3–5 marks each.
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