🌿 Class 10 Biology — Life Processes Complete MASTER NOTES
CBSE Board 2026 | Full Detailed Notes + NCERT Line + PYQ + Tricks + Important Diagrams + Board Answers
📖 CHAPTER INTRODUCTION
All living organisms perform certain basic activities to stay alive. These activities are called Life Processes.
🌟 Main Life Processes
| Life Process | Function |
|---|---|
| Nutrition | Obtaining food |
| Respiration | Releasing energy |
| Transportation | Transporting materials |
| Excretion | Removing wastes |
WHY ARE LIFE PROCESSES NECESSARY? ⭐
Life processes are necessary for:
- Growth
- Repair
- Energy production
- Survival
- Maintenance of body
🌱 1. NUTRITION
Definition
The process by which organisms obtain food and utilize it is called nutrition.
TYPES OF NUTRITION
| Type | Meaning | Example |
|---|---|---|
| Autotrophic | Makes own food | Green plants |
| Heterotrophic | Depends on others | Humans |
🌞 AUTOTROPHIC NUTRITION
Green plants prepare food by photosynthesis.
🌿 PHOTOSYNTHESIS
Definition
The process by which green plants synthesize food from carbon dioxide and water in the presence of sunlight and chlorophyll.
📌 Photosynthesis Equation
🌟 CONDITIONS NECESSARY FOR PHOTOSYNTHESIS
- Sunlight
- Chlorophyll
- Carbon dioxide
- Water
🌟 RAW MATERIALS
| Substance | Source |
|---|---|
| Water | Soil |
| Carbon dioxide | Atmosphere |
| Sunlight | Sun |
| Chlorophyll | Green leaves |
🌟 EVENTS OF PHOTOSYNTHESIS
- Absorption of light energy
- Conversion into chemical energy
- Splitting of water molecules
- Reduction of CO₂ into carbohydrates
🌿 STOMATA
Definition
Tiny pores present on the surface of leaves.
🌟 FUNCTIONS OF STOMATA
- Exchange of gases
- Transpiration
- Helps in photosynthesis
🌿 Stomata Diagram
🌟 GUARD CELLS
Guard cells control opening and closing of stomata.
🌟 IMPORTANT NCERT LINES
- Chlorophyll is essential for photosynthesis.
- Oxygen is released during photosynthesis.
- Starch is stored in leaves.
🌟 TEST FOR STARCH
Iodine Test:
Blue-black colour confirms presence of starch.
🌟 IMPORTANT BOARD QUESTION
Q. Why do desert plants open stomata at night?
Answer:
To reduce water loss during daytime.
🍔 HETEROTROPHIC NUTRITION
Organisms obtain food from others.
TYPES OF HETEROTROPHIC NUTRITION
| Type | Example |
|---|---|
| Holozoic | Human |
| Saprophytic | Fungi |
| Parasitic | Cuscuta |
🍕 HUMAN DIGESTIVE SYSTEM
🌟 HUMAN DIGESTIVE SYSTEM DIAGRAM
🌟 ALIMENTARY CANAL
Mouth → Oesophagus → Stomach → Small intestine → Large intestine → Rectum → Anus
🌟 STEPS OF NUTRITION
- Ingestion
- Digestion
- Absorption
- Assimilation
- Egestion
👄 1. MOUTH
Functions:
- Intake of food
- Chewing
- Mixing with saliva
🌟 SALIVA
Contains enzyme salivary amylase.
🌟 FUNCTION OF SALIVARY AMYLASE
Converts starch into simple sugar.
🌟 TONGUE FUNCTIONS
- Mixing food
- Taste sensation
- Swallowing
🌟 PERISTALTIC MOVEMENT
Wave-like movement of alimentary canal that pushes food forward.
🍲 2. STOMACH
🌟 GASTRIC GLANDS SECRETE
| Substance | Function |
|---|---|
| Hydrochloric acid | Makes acidic medium |
| Pepsin | Digests proteins |
| Mucus | Protects stomach wall |
🌟 ROLE OF HCl
- Kills germs
- Activates pepsin
- Creates acidic medium
🌟 WHY STOMACH DOES NOT DIGEST ITSELF?
Because mucus protects inner lining.
🌟 PEPSIN
Converts proteins into peptones.
🌟 IMPORTANT PYQ
Q. Why is HCl necessary in stomach?
Answer:
It creates acidic medium and activates pepsin enzyme.
🌟 3. SMALL INTESTINE ⭐ MOST IMPORTANT
Longest part of alimentary canal.
RECEIVES:
- Bile juice from liver
- Pancreatic juice from pancreas
🌟 LIVER
Largest gland in body.
🌟 BILE JUICE FUNCTIONS
- Neutralizes acidic food
- Breaks fats into smaller globules
🌟 PANCREATIC JUICE
Contains:
- Trypsin
- Lipase
- Amylase
🌟 FUNCTIONS
| Enzyme | Function |
|---|---|
| Trypsin | Protein digestion |
| Lipase | Fat digestion |
| Amylase | Starch digestion |
🌟 INTESTINAL JUICE
Completes digestion.
🌟 VILLI
Finger-like projections in small intestine.
🌟 FUNCTIONS OF VILLI
- Increase surface area
- Absorb digested food
🌟 Villi Diagram
🌟 LARGE INTESTINE
Functions:
- Water absorption
- Storage of undigested food
🌬️ 2. RESPIRATION
Definition
The process of breaking down food to release energy.
🌟 TYPES OF RESPIRATION
| Type | Oxygen Required |
|---|---|
| Aerobic | Yes |
| Anaerobic | No |
🌟 AEROBIC RESPIRATION
Occurs in presence of oxygen.
Equation
🌟 ANAEROBIC RESPIRATION
Occurs in absence of oxygen.
In Yeast
🌟 HUMAN RESPIRATORY SYSTEM
🌟 PATH OF AIR
Nostrils → Nasal cavity → Pharynx → Larynx → Trachea → Bronchi → Bronchioles → Alveoli
🌟 TRACHEA
Windpipe supported by cartilage rings.
🌟 ALVEOLI ⭐ VERY IMPORTANT
Tiny air sacs in lungs.
FEATURES OF ALVEOLI
- Thin walls
- Moist surface
- Rich blood supply
- Large surface area
🌟 FUNCTIONS OF ALVEOLI
Exchange of gases.
🌟 GAS EXCHANGE
| Gas | Movement |
|---|---|
| Oxygen | Alveoli → Blood |
| Carbon dioxide | Blood → Alveoli |
🌟 IMPORTANT BOARD QUESTION
Q. Why are alveoli suitable for gas exchange?
Answer:
Because they provide large surface area, thin walls and rich blood supply.
❤️ 3. TRANSPORTATION
🌟 TRANSPORTATION IN HUMAN BEINGS
Transport system = Circulatory system
❤️ BLOOD
Fluid connective tissue.
🌟 COMPONENTS OF BLOOD
| Component | Function |
|---|---|
| RBC | Transport oxygen |
| WBC | Fight infection |
| Platelets | Blood clotting |
| Plasma | Transport materials |
🌟 RBC
Contains haemoglobin.
🌟 HAEMOGLOBIN
Red pigment that carries oxygen.
❤️ HUMAN HEART
🌟 HEART DIAGRAM
🌟 CHAMBERS OF HEART
- Right atrium
- Right ventricle
- Left atrium
- Left ventricle
🌟 DOUBLE CIRCULATION
Blood passes through heart twice in one complete cycle.
🌟 ADVANTAGES
- Efficient oxygen supply
- No mixing of blood
- More energy production
🌟 BLOOD VESSELS
| Vessel | Feature |
|---|---|
| Arteries | Thick walls |
| Veins | Thin walls |
| Capillaries | Very thin walls |
🌟 ARTERIES
Carry blood away from heart.
🌟 VEINS
Carry blood toward heart.
🌟 VALVES IN VEINS
Prevent backward flow of blood.
🌟 BLOOD PRESSURE
Pressure exerted by blood on artery walls.
🌟 LYMPH
Fluid tissue helping in transportation and immunity.
🌱 TRANSPORTATION IN PLANTS
🌟 XYLEM
Transports water and minerals.
🌟 PHLOEM
Transports food.
🌟 Plant Transportation Diagram
🌟 TRANSPIRATION
Loss of water through stomata.
🌟 IMPORTANCE OF TRANSPIRATION
- Cooling effect
- Helps ascent of sap
- Maintains water cycle
🚽 4. EXCRETION
🌟 Definition
Removal of metabolic wastes from body.
🌟 HUMAN EXCRETORY SYSTEM
🌟 PARTS OF EXCRETORY SYSTEM
| Organ | Function |
|---|---|
| Kidney | Filters blood |
| Ureter | Carries urine |
| Urinary bladder | Stores urine |
| Urethra | Expels urine |
🌟 NEPHRON ⭐ MOST IMPORTANT
Functional unit of kidney.
🌟 FUNCTIONS OF NEPHRON
- Ultrafiltration
- Reabsorption
- Urine formation
🌟 DIALYSIS
Artificial purification of blood.
🌟 ARTIFICIAL KIDNEY
Machine used for dialysis.
🔥 MOST IMPORTANT PYQs
Q1. Explain double circulation.
Q2. Why are alveoli suitable for gas exchange?
Q3. State functions of xylem and phloem.
Q4. Explain role of HCl in stomach.
Q5. Why are valves present in veins?
Q6. Draw and explain nephron.
Q7. Differentiate between aerobic and anaerobic respiration.
📌 DIFFERENCES IMPORTANT FOR BOARDS
Aerobic vs Anaerobic Respiration
| Aerobic | Anaerobic |
|---|---|
| Oxygen needed | Oxygen absent |
| More energy | Less energy |
| Complete breakdown | Incomplete breakdown |
Artery vs Vein
| Artery | Vein |
|---|---|
| Thick walls | Thin walls |
| No valves | Valves present |
| Blood away from heart | Blood toward heart |
Xylem vs Phloem
| Xylem | Phloem |
|---|---|
| Water transport | Food transport |
| Upward movement | Both directions |
🧠 SUPER TRICKS
Heart Chambers:
“RAM-LAK”
Blood Components:
“RWP-P”
Digestive Sequence:
“MOSSLRA”
Functions of Blood:
“CFT”
- Carry
- Fight
- Transport
✍️ MOST IMPORTANT DIAGRAMS FOR CBSE
- Human Digestive System
- Stomata
- Villi
- Respiratory System
- Human Heart
- Double Circulation
- Xylem & Phloem
- Nephron
🎯 BOARD EXAM TIPS
✅ Learn all diagrams with labels
✅ Practice NCERT back questions
✅ Revise differences daily
✅ Learn all functions word-to-word
✅ Practice PYQs regularly
✅ Write keywords in answers
🔥 EXPECTED QUESTIONS 2026
- Explain photosynthesis with diagram.
- Explain digestion in humans.
- Explain double circulation.
- Explain transportation in plants.
- Draw nephron and explain urine formation.
- Difference between artery and vein.
- Why is small intestine long in herbivores?
- Explain role of alveoli.
