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By rohit.pandey1
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Updated on 29 Jun 2026, 15:02 IST
Life Processes is Chapter 5 of NCERT Class 10 Science and one of the most important Biology chapters for CBSE board exam preparation. This chapter explains the basic processes that keep living organisms alive, such as nutrition, respiration, transportation, and excretion.
These Life Processes Class 10 Notes are prepared in a simple and exam-focused format to help students revise the complete chapter quickly. The notes cover autotrophic nutrition, heterotrophic nutrition, photosynthesis, nutrition in Amoeba, human digestive system, respiration in plants and animals, aerobic and anaerobic respiration, transportation in humans, double circulation, transportation in plants, xylem and phloem, excretion in humans, nephron structure and function, haemodialysis, and excretion in plants.
Students can use these notes for school exams, pre-board exams, CBSE Board Class 10 Sciece Revision Notes, MCQs, assertion-reason questions, case-based questions, previous year questions, and quick last-minute revision.
Life processes are the basic activities that living organisms perform to maintain life. In Class 10 Science, this chapter mainly focuses on four important life processes: nutrition, respiration, transportation, and excretion.
A simple way to remember them is the RENT mnemonic:
R – Respiration
E – Excretion
N – Nutrition
T – Transportation
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| Life Process | Meaning | Why It is Important |
| Nutrition | Taking in and using food | Provides energy and raw materials |
| Respiration | Breaking down food to release energy | Produces ATP for body activities |
| Transportation | Movement of substances inside the body | Carries food, oxygen, water, hormones, and wastes |
| Excretion | Removal of metabolic wastes | Prevents toxic substances from accumulating |
Students can download the Life Processes Class 10 Notes PDF for offline revision. The PDF includes chapter summary, diagrams, flowcharts, comparison tables, important definitions, MCQs, assertion-reason questions, case-based questions, and previous year question patterns.
Life processes are the essential biological processes that living organisms need to survive. These processes continue even when an organism is resting or not doing any visible activity.
Living organisms need energy for growth, repair, movement, reproduction, transport of materials, and removal of wastes. Life processes help organisms obtain energy, use nutrients, exchange gases, transport substances, and remove harmful waste products.
Nutrition is the process by which an organism takes in food and uses it for energy, growth, repair, and maintenance. All living organisms need nutrition because food provides energy and raw materials required for life processes.
There are two main modes of nutrition:
Autotrophic nutrition is a mode of nutrition in which organisms prepare their own food from simple inorganic substances such as carbon dioxide and water. Green plants show autotrophic nutrition through photosynthesis.
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Autotrophs are also called producers because they produce food for themselves and indirectly for other organisms.
Heterotrophic nutrition is a mode of nutrition in which organisms depend on other organisms for food. Animals, fungi, and many microorganisms show heterotrophic nutrition.
| Type | Meaning | Example |
| Holozoic nutrition | Food is ingested, digested, absorbed, and assimilated | Humans, Amoeba |
| Saprophytic nutrition | Organism feeds on dead and decaying matter | Fungi, bacteria |
| Parasitic nutrition | Organism obtains food from a living host | Cuscuta, tapeworm |
| Basis | Autotrophic Nutrition | Heterotrophic Nutrition |
| Food source | Organism prepares its own food | Organism depends on others |
| Raw materials | CO₂, H₂O, sunlight | Plants or animals |
| Chlorophyll | Usually present | Absent |
| Example | Green plants | Humans, animals, fungi |
| Role in ecosystem | Producers | Consumers or decomposers |
Photosynthesis is the process by which green plants prepare food using carbon dioxide, water, sunlight, and chlorophyll. During photosynthesis, glucose is formed and oxygen is released as a by-product.
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
In words:
Carbon dioxide + Water → Glucose + Oxygen
Conditions required:
Sunlight and chlorophyll
| Requirement | Source |
| Carbon dioxide | Enters leaves through stomata |
| Water | Absorbed by roots from soil |
| Sunlight | Trapped by chlorophyll |
| Chlorophyll | Present in chloroplasts of green leaves |
Photosynthesis takes place mainly in the chloroplasts of leaf cells.
Oxygen is not a raw material for photosynthesis. Oxygen is released as a by-product during the splitting of water.
Stomata are tiny pores present on the surface of leaves. They help in the exchange of gases during photosynthesis and respiration.
Guard cells control the opening and closing of stomata. When guard cells become swollen, the stomatal pore opens. When guard cells lose water and become flaccid, the stomatal pore closes.
| Structure | Function |
| Stomata | Exchange of CO₂, O₂, and water vapour |
| Guard cells | Control opening and closing of stomata |
| Chloroplast | Site of photosynthesis |
| Chlorophyll | Traps sunlight |
Yes, plants respire during day and night. Respiration occurs 24 hours a day because plant cells continuously need energy. Photosynthesis occurs only during the day in the presence of sunlight.
During the day, the rate of photosynthesis is usually higher than the rate of respiration, so plants release oxygen as the net effect. At night, photosynthesis stops and only respiration occurs, so plants release carbon dioxide.
| Time | Photosynthesis | Respiration | Net Gas Released |
| Day | Occurs | Occurs | Mostly O₂ |
| Night | Does not occur | Occurs | CO₂ |
| Early morning / evening | Low rate | Occurs | Depends on light intensity |
Common Mistake:
Plants do not respire only at night. They respire all the time.
Amoeba shows holozoic nutrition. It takes in food using temporary finger-like projections called pseudopodia. The food is enclosed in a food vacuole, digested, absorbed, and the undigested material is removed from the body.
| Step | Explanation |
| Ingestion | Amoeba surrounds food using pseudopodia |
| Digestion | Food is digested inside food vacuole |
| Absorption | Digested food passes into cytoplasm |
| Assimilation | Absorbed food is used for energy and growth |
| Egestion | Undigested food is thrown out |
| Basis | Amoeba | Paramoecium |
| Movement of food | Food can be taken from any body surface | Food enters through a fixed oral groove |
| Feeding structure | Pseudopodia | Cilia |
| Food vacuole | Formed around food | Food moves into food vacuole through oral groove |
| Type of nutrition | Holozoic | Holozoic |
The human digestive system breaks complex food into simpler substances that can be absorbed and used by the body. It includes the alimentary canal and associated glands.
The main organs of the alimentary canal are mouth, oesophagus, stomach, small intestine, large intestine, rectum, and anus. The main digestive glands are salivary glands, liver, pancreas, and intestinal glands.
Food passes through the digestive system in this order:
Mouth → Oesophagus → Stomach → Small intestine → Large intestine → Rectum → Anus
My Old Stomach Stores Large Round Apples
Mouth → Oesophagus → Stomach → Small intestine → Large intestine → Rectum → Anus
Food is chewed by teeth and mixed with saliva. Saliva contains the enzyme salivary amylase, which begins the digestion of starch.
Starch → Simple sugars
The tongue helps in mixing food with saliva and swallowing.
The oesophagus carries food from mouth to stomach. Food moves through the oesophagus by wave-like muscular movements called peristalsis.
The stomach is a muscular bag where food is mixed with gastric juice. Gastric juice contains hydrochloric acid, pepsin, and mucus.
| Component | Function |
| HCl | Makes the medium acidic and kills harmful microbes |
| Pepsin | Digests proteins |
| Mucus | Protects stomach lining from acid |
Hydrochloric acid makes the stomach medium acidic so that pepsin can work properly. It also kills harmful bacteria that enter with food.
The small intestine is the main site of complete digestion and absorption. It receives bile from the liver and pancreatic juice from the pancreas.
Bile does not chemically digest fats. It emulsifies fats, which means it breaks large fat globules into smaller droplets. This helps lipase act more efficiently.
| Function | Explanation |
| Emulsifies fat | Breaks large fat globules into smaller droplets |
| Makes medium alkaline | Helps pancreatic enzymes work |
| Helps fat digestion indirectly | Provides more surface area for lipase |
The small intestine has finger-like projections called villi. Villi increase the surface area for absorption of digested food.
Each villus has blood capillaries and lymph vessels that help transport absorbed nutrients.
Villi increase the surface area of the small intestine, making absorption of digested food faster and more efficient.
The large intestine mainly absorbs water and salts from undigested food. The remaining waste is stored in the rectum and removed through the anus.
| Organ / Gland | Juice / Enzyme | Acts On | Product |
| Salivary glands | Salivary amylase | Starch | Simple sugars |
| Stomach | Pepsin | Proteins | Smaller protein fragments |
| Liver | Bile | Fats | Emulsifies fats |
| Pancreas | Trypsin | Proteins | Smaller peptides |
| Pancreas | Lipase | Fats | Fatty acids and glycerol |
| Pancreas | Amylase | Carbohydrates | Simple sugars |
| Small intestine | Intestinal enzymes | Carbohydrates, proteins, fats | Final digestion products |
Respiration is the process by which food is broken down inside cells to release energy. The energy released is stored in the form of ATP, which is used for various life processes.
Respiration is different from breathing. Breathing is only the physical process of inhaling oxygen and exhaling carbon dioxide, while respiration is a chemical process that releases energy from food.
| Basis | Breathing | Respiration |
| Type of process | Physical process | Chemical process |
| Site | Lungs | Cells |
| Energy release | No energy is released | Energy is released |
| Enzymes | Not involved | Enzymes are involved |
| Meaning | Taking in O₂ and giving out CO₂ | Breakdown of glucose to release ATP |
The first step of respiration is the breakdown of glucose into pyruvate. This takes place in the cytoplasm.
Glucose → Pyruvate + Energy
After pyruvate is formed, different pathways may occur depending on the presence or absence of oxygen.
Aerobic respiration occurs in the presence of oxygen. Glucose is completely broken down into carbon dioxide and water, releasing a large amount of energy.
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy
Anaerobic respiration occurs in the absence of oxygen. Glucose is incompletely broken down and less energy is released.
Glucose → Ethanol + CO₂ + Energy
This process is called fermentation. It is used in bread making and alcohol production.
During heavy exercise, our muscles may not get enough oxygen. Pyruvate is converted into lactic acid, which may cause muscle cramps.
Glucose → Lactic acid + Energy
| Basis | Aerobic Respiration | Anaerobic Respiration |
| Oxygen | Required | Not required |
| Breakdown of glucose | Complete | Incomplete |
| Energy released | More | Less |
| End products | CO₂ and H₂O | Ethanol + CO₂ or lactic acid |
| Site | Mitochondria after first step | Cytoplasm |
| Example | Humans during normal activity | Yeast, muscles during heavy exercise |
During exercise, muscles need more energy. To release more energy, cells need more oxygen for aerobic respiration. Therefore, breathing rate increases to supply more oxygen and remove extra carbon dioxide.
The human respiratory system helps in the exchange of gases. Oxygen is taken into the body and carbon dioxide is removed.
Nostrils → Nasal cavity → Pharynx → Larynx → Trachea → Bronchi → Bronchioles → Alveoli
Alveoli are tiny balloon-like structures in the lungs. They provide a large surface area for the exchange of gases.
| Feature of Alveoli | Importance |
| Thin walls | Faster diffusion of gases |
| Large surface area | More gas exchange |
| Rich blood supply | Oxygen enters blood and CO₂ leaves blood |
| Moist surface | Helps gases dissolve and diffuse |
Transportation is the movement of materials such as oxygen, carbon dioxide, food, hormones, and wastes inside the body. In humans, transportation occurs through blood, blood vessels, and the heart.
Blood is a fluid connective tissue because it connects different parts of the body by transporting substances.
| Component | Function |
| Plasma | Transports food, hormones, CO₂, and wastes |
| Red blood cells | Carry oxygen using haemoglobin |
| White blood cells | Fight infections |
| Platelets | Help in blood clotting |
| Blood Vessel | Function | Wall | Direction of Blood Flow |
| Arteries | Carry blood away from heart | Thick and elastic | Heart to body parts |
| Veins | Carry blood towards heart | Thin walls, valves present | Body parts to heart |
| Capillaries | Exchange materials with tissues | Very thin, one-cell thick | Connect arteries and veins |
Arteries do not always carry oxygenated blood. The pulmonary artery carries deoxygenated blood from the heart to the lungs. The pulmonary vein carries oxygenated blood from the lungs to the heart.
The human heart is a muscular organ that pumps blood throughout the body. It has four chambers: right atrium, right ventricle, left atrium, and left ventricle.
| Chamber | Receives / Pumps Blood |
| Right atrium | Receives deoxygenated blood from body |
| Right ventricle | Pumps deoxygenated blood to lungs |
| Left atrium | Receives oxygenated blood from lungs |
| Left ventricle | Pumps oxygenated blood to the body |
The left ventricle has thicker muscular walls because it pumps oxygenated blood to the entire body. The right ventricle pumps blood only to the lungs, so it has comparatively thinner walls.
Double circulation means blood passes through the heart twice during one complete cycle. It includes pulmonary circulation and systemic circulation.
Double circulation is necessary in humans and birds because it keeps oxygenated and deoxygenated blood separate and ensures efficient oxygen supply to body tissues.
| Type | Pathway | Function |
| Pulmonary circulation | Heart → Lungs → Heart | Oxygenates blood |
| Systemic circulation | Heart → Body → Heart | Supplies oxygenated blood to body |
Plants need transportation to move water, minerals, and food from one part to another. Water and minerals are transported by xylem, while food is transported by phloem.
| Basis | Xylem | Phloem |
| Material transported | Water and minerals | Food / sugar |
| Direction | Mostly upward | Both upward and downward |
| Type of cells | Mostly dead cells | Living cells |
| Energy requirement | Does not usually require energy | Requires energy |
| Driving force | Transpiration pull and root pressure | Translocation using ATP |
| Movement | Roots to leaves | Source to sink |
| Example of source/sink | Roots absorb water | Leaves are source; storage organs are sink |
Water moves upward in plants through xylem due to root pressure and transpiration pull.
Root cells absorb water and minerals from the soil. This creates a pressure that pushes water upward.
Transpiration is the loss of water vapour from leaves through stomata. As water evaporates from leaves, it creates a pull that draws water upward through xylem.
Translocation is the movement of food from leaves to other parts of the plant through phloem. Food moves from the source to the sink.
| Term | Meaning |
| Source | Region where food is prepared, usually leaves |
| Sink | Region where food is stored or used, such as roots, fruits, seeds, or growing parts |
Phloem transport requires energy in the form of ATP because food may move both upward and downward.
Excretion is the process of removing harmful metabolic wastes from the body. In humans, the main excretory organs are kidneys. The main nitrogenous waste removed from the body is urea.
The human excretory system includes:
| Part | Function |
| Kidneys | Filter blood and form urine |
| Ureters | Carry urine from kidneys to urinary bladder |
| Urinary bladder | Stores urine temporarily |
| Urethra | Removes urine from the body |
The nephron is the structural and functional unit of the kidney. Each kidney has many nephrons that filter blood and form urine.
| Part | Function |
| Bowman's capsule | Cup-shaped structure that collects filtrate |
| Glomerulus | Network of capillaries where filtration occurs |
| Tubule | Reabsorbs useful substances and secretes extra wastes |
| Collecting duct | Collects urine from many nephrons |
Urine formation occurs in three main steps:
Blood enters the glomerulus under pressure. Small molecules such as water, glucose, salts, amino acids, and urea pass into Bowman’s capsule. Blood cells and large proteins do not pass through.
Useful substances such as glucose, amino acids, salts, and most water are reabsorbed into the blood from the tubule.
Extra wastes and ions are secreted into the tubule. The remaining fluid becomes urine.
| Feature | Glomerular Filtrate | Final Urine |
| Contains water | Yes | Yes |
| Contains glucose | Yes | Usually no |
| Contains amino acids | Yes | Usually no |
| Contains urea | Yes | Yes |
| Contains salts | Yes | Some salts |
| Contains blood cells | No | No |
| Contains large proteins | No | No |
| Formation site | Bowman’s capsule | Collecting duct / urinary passage |
| Main difference | Contains useful substances | Useful substances mostly reabsorbed |
Haemodialysis is an artificial method of removing wastes from the blood when kidneys are not functioning properly. It is used for patients with kidney failure.
In haemodialysis, blood is passed through a machine called a dialyser. The dialyser removes urea, extra salts, and excess water from the blood before returning the cleaned blood to the body.
Plants also produce waste products, but they remove them in different ways. Since plants do not have a special excretory system, they store or remove wastes through leaves, bark, vacuoles, roots, and other structures.
| Method | Example |
| Diffusion of gases | O₂ and CO₂ move out through stomata |
| Storage in vacuoles | Waste substances stored inside cells |
| Storage in leaves | Leaves fall off and remove wastes |
| Storage in bark | Wastes removed when bark peels |
| Excretion into soil | Some wastes are released through roots |
| Formation of useful products | Gums, resins, tannins, latex, essential oils |
Alveoli and nephrons both have large surface area and rich blood supply, but they perform different functions. Alveoli help in gas exchange, while nephrons help in filtration of blood and urine formation.
| Basis | Alveoli | Nephron |
| Organ | Lungs | Kidney |
| Main function | Exchange of O₂ and CO₂ | Filtration of blood |
| Surface area | Large surface area for diffusion | Large surface area for filtration and reabsorption |
| Blood supply | Rich blood supply | Rich blood supply |
| Final result | Oxygenated blood | Urine formation |
Students should practise diagrams because this chapter often includes diagram-based and labelling questions.
| Diagram | Important Labels |
| Human digestive system | Mouth, oesophagus, stomach, liver, pancreas, small intestine, large intestine |
| Human respiratory system | Nasal cavity, trachea, bronchi, lungs, alveoli, diaphragm |
| Human heart | Right atrium, right ventricle, left atrium, left ventricle, aorta, vena cava, pulmonary artery, pulmonary vein |
| Nephron | Bowman’s capsule, glomerulus, tubule, collecting duct |
| Leaf cross-section | Stomata, guard cells, chloroplast, xylem, phloem |
| Nutrition in Amoeba | Pseudopodia, food vacuole, nucleus |
| Photosynthesis experiment | Leaf, iodine test, starch region |
Lab activities are important because CBSE often asks observation-based and reasoning-based questions.
This activity shows that starch is formed during photosynthesis.
The leaf turns blue-black, showing the presence of starch.
Starch is produced during photosynthesis.
In a variegated leaf, only the green parts contain chlorophyll. After the iodine test, only green parts turn blue-black. This shows that chlorophyll is necessary for photosynthesis.
When germinating seeds are kept in a closed setup, they release carbon dioxide during respiration. The CO₂ can turn lime water milky.
Respiration produces carbon dioxide.
If stomata are blocked with petroleum jelly, gas exchange and transpiration reduce. Carbon dioxide cannot enter the leaf properly, so photosynthesis decreases. Water vapour also cannot escape easily, so transpiration is reduced.
| Concept | Real-life Application |
| Photosynthesis | Plants produce food and release oxygen |
| Anaerobic respiration in yeast | Bread dough rises due to CO₂ |
| Breathing rate | Increases during exercise due to higher oxygen demand |
| Villi | Help absorb nutrients from food |
| Glucose drip | Provides quick energy to patients |
| Double circulation | Supplies oxygen efficiently to body tissues |
| Platelets | Help stop bleeding by clotting blood |
| Transpiration | Helps water move upward in tall plants |
| Dialysis | Helps kidney failure patients remove wastes |
| Plant excretion | Gums and resins are useful plant products |
| Common Mistake | Correct Concept |
| Plants respire only at night | Plants respire day and night |
| Breathing and respiration are same | Breathing is physical; respiration is chemical |
| Oxygen is a raw material for photosynthesis | Oxygen is a by-product of photosynthesis |
| Bile digests fats | Bile emulsifies fats; lipase digests fats |
| Arteries always carry oxygenated blood | Pulmonary artery carries deoxygenated blood |
| Veins always carry deoxygenated blood | Pulmonary vein carries oxygenated blood |
| Xylem transports food | Xylem transports water and minerals |
| Phloem transports only downward | Phloem transports both upward and downward |
| Urine contains glucose normally | Glucose is usually reabsorbed |
| Large intestine completes digestion | Large intestine mainly absorbs water and salts |
A. Mitochondria
B. Chloroplast
C. Ribosome
D. Nucleus
Answer: B. Chloroplast
A. Pepsin
B. Trypsin
C. Salivary amylase
D. Lipase
Answer: C. Salivary amylase
A. Chemically breaking fats into amino acids
B. Emulsifying fats
C. Digesting proteins
D. Absorbing glucose
Answer: B. Emulsifying fats
A. Alveolus
B. Nephron
C. Villus
D. Platelet
Answer: B. Nephron
A. Pulmonary artery
B. Pulmonary vein
C. Aorta
D. Vena cava
Answer: A. Pulmonary artery
Assertion: Plants respire during both day and night.
Reason: Plant cells need energy continuously for life processes.
Answer: Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
Assertion: Bile does not digest fat chemically.
Reason: Bile emulsifies large fat globules into smaller droplets.
Answer: Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
Assertion: The left ventricle has thicker walls than the right ventricle.
Reason: The left ventricle pumps blood to the entire body.
Answer: Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
A student places a healthy potted plant in sunlight after keeping it in the dark for 48 hours. One leaf is partly covered with black paper, while another leaf is coated with petroleum jelly. After a few hours, the student tests the leaves with iodine solution.
To score well in Life Processes Class 10, focus on photosynthesis, human digestion, enzymes, respiration pathways, human heart, double circulation, xylem and phloem, nephron, urine formation, and excretion in plants. Practise diagrams and tables regularly because this chapter is commonly tested through MCQs, assertion-reason questions, case-based questions, and diagram-based questions.
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The main life processes in Class 10 are nutrition, respiration, transportation, and excretion. These processes help organisms obtain energy, use food, transport substances, and remove harmful wastes.
Autotrophic nutrition occurs when organisms make their own food using simple substances like CO₂ and water. Heterotrophic nutrition occurs when organisms depend on other organisms for food.
Photosynthesis is the process by which green plants prepare glucose using carbon dioxide, water, sunlight, and chlorophyll. Oxygen is released as a by-product.
Yes, plants respire at night. Plants respire during both day and night. During the day, photosynthesis also occurs, so the net release is usually oxygen. At night, only respiration occurs, so carbon dioxide is released.
Breathing is the physical process of inhaling oxygen and exhaling carbon dioxide. Respiration is the chemical process in which glucose is broken down inside cells to release energy.
Bile emulsifies fats by breaking large fat globules into smaller droplets. It does not chemically digest fats. It helps lipase act more efficiently on fats.
Double circulation is necessary because it keeps oxygenated and deoxygenated blood separate. This ensures efficient oxygen supply to body tissues and supports high energy needs.
Villi increase the surface area of the small intestine for absorption of digested food. They contain blood capillaries and lymph vessels that help transport absorbed nutrients.
Xylem transports water and minerals mainly upward from roots to leaves. Phloem transports food from leaves to different parts of the plant in both upward and downward directions.
Nephron is the structural and functional unit of the kidney. It filters blood, reabsorbs useful substances, secretes extra wastes, and helps form urine.
Haemodialysis is an artificial method of filtering blood when kidneys fail. It removes urea, extra salts, and excess water from the blood using a dialyser.
Plants excrete wastes through diffusion of gases, storage in vacuoles, shedding of leaves and bark, release through roots, and formation of substances like gums, resins, tannins, latex, and essential oils.