NCERT Class 10 Science Chapter 5 – Life Processes

NCERT Class 10 Science Chapter 5 explains the essential biological functions required to maintain life. In NCERT Class 10 Science Chapter 5, students study how organisms obtain energy, transport materials, and remove wastes.

The chapter begins with the concept of life processes, which include nutrition, respiration, transportation, and excretion. These processes help organisms maintain internal balance and survive.

A major section of NCERT Class 10 Science Chapter 5 focuses on nutrition. Nutrition is of two types:

• Autotrophic nutrition – Green plants prepare food through photosynthesis.
  Equation:
  6CO₂ + 12H₂O → C₆H₁₂O₆ + 6O₂ + 6H₂O
• Heterotrophic nutrition – Organisms depend on others for food (saprophytic, parasitic, holozoic).

In humans, digestion begins in the mouth with salivary amylase, continues in the stomach with HCl, and absorption occurs in the small intestine (villi).

Another important part of NCERT Class 10 Science Chapter 5 is respiration. Glucose is broken down to release energy in the form of ATP. Aerobic respiration occurs in mitochondria, while anaerobic respiration produces lactic acid (in muscles) or ethanol (in yeast).

The chapter also explains transportation:

• In humans – through the circulatory system (heart, blood, blood vessels).
• Humans show double circulation and the heart has four chambers.
• In plants – through xylem (water) and phloem (food).

Finally, excretion removes metabolic wastes. In humans, the nephron is the functional unit of the kidney. In plants, wastes are removed through transpiration, diffusion, and storage.

For exams, NCERT Class 10 Science Chapter 5 is highly important as it forms the foundation of human physiology and plant biology. Students should refer to the official NCERT website at for authentic textbooks and syllabus updates.

For structured preparation of NCERT Class 9–12 for UPSC, BPSC and State PCS examinations, strengthen your basics with our complete NCERT Book Notes PDF for Class 9-12, available inside the NCERT foundation course level-2.

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5.1 What are Life Processes?

• Life processes are the basic functions that maintain and sustain life in living organisms
• All living organisms perform essential processes such as nutrition, respiration, transportation, and excretion
• These processes help in obtaining energy, maintaining body structure, and ensuring proper functioning of the body
• Growth and movement alone are not sufficient to define life; even plants, which do not show visible movement, perform vital life processes
• The energy required for life processes is obtained from food, which is broken down during respiration
• Continuous interaction between living organisms and their environment is necessary to maintain homeostasis (internal balance)
• Unicellular organisms carry out life processes using a single cell, while multicellular organisms have specialised tissues and organs

5.2 Nutrition

• Nutrition is the process by which organisms obtain and utilise food for energy, growth, repair, and maintenance
• Food provides energy, raw materials for growth, and substances needed for proper functioning of the body
• Organisms require nutrients such as carbohydrates, proteins, fats, vitamins, and minerals
• Based on the mode of obtaining food, nutrition is classified into autotrophic and heterotrophic
• In autotrophic nutrition, organisms prepare their own food from simple inorganic substances
• In heterotrophic nutrition, organisms depend on other organisms for their food
• Different organisms show different methods of nutrition depending on their body structure and habitat

5.2.1 Autotrophic Nutrition

• Autotrophic nutrition is the mode of nutrition in which organisms prepare their own food from inorganic substances like carbon dioxide (CO₂) and water (H₂O)
• Green plants and some bacteria are autotrophs because they contain chlorophyll, which helps in trapping sunlight
• The process by which green plants prepare food is called photosynthesis
• During photosynthesis, carbon dioxide and water are converted into glucose (C₆H₁₂O₆) in the presence of sunlight and chlorophyll
• The overall chemical equation of photosynthesis is:
  6CO₂ + 12H₂O → C₆H₁₂O₆ + 6O₂ + 6H₂O
• Photosynthesis occurs in the chloroplasts of plant cells
• Oxygen released during photosynthesis is essential for the survival of most living organisms

5.2.2 Heterotrophic Nutrition

• Heterotrophic nutrition is the mode of nutrition in which organisms depend on other organisms for food
• Heterotrophs cannot prepare their own food and obtain ready-made organic substances
• Based on the method of obtaining food, heterotrophic nutrition is of three types: saprophytic, parasitic, and holozoic
• Saprophytes feed on dead and decaying organic matter by secreting digestive enzymes outside the body
• Parasites obtain food from a living host, often causing harm to the host
• Holozoic nutrition involves ingestion, digestion, absorption, assimilation, and egestion; it is seen in humans and animals
• Different organisms show different heterotrophic methods depending on their structure and environment

5.2.3 How do Organisms obtain their Nutrition?

• Different organisms have developed various methods and structures to obtain food depending on their complexity
• In unicellular organisms like Amoeba, food is engulfed by forming pseudopodia, and digestion occurs inside a food vacuole
• In multicellular organisms, specialised organs are present to perform different functions related to nutrition
• In simple organisms, the entire body surface may be involved in absorption of nutrients
• Complex organisms have a well-developed digestive system for ingestion, digestion, absorption, and egestion
• The process of nutrition involves several steps such as intake of food, breakdown into simpler substances, absorption, and removal of undigested material
• The level of organisation in an organism determines the method of obtaining nutrition

5.2.4 Nutrition in Human Beings

• Human beings follow holozoic nutrition, which includes the steps of ingestion, digestion, absorption, assimilation, and egestion
• The digestive system consists of the alimentary canal and associated glands such as salivary glands, liver, and pancreas
• Digestion begins in the mouth, where food is chewed and mixed with saliva containing the enzyme salivary amylase, which breaks down starch
• The food passes through the oesophagus to the stomach, where it is mixed with gastric juice containing hydrochloric acid (HCl) and enzymes
• In the small intestine, bile from the liver emulsifies fats and pancreatic juice helps in digestion of carbohydrates, proteins, and fats
• The digested food is absorbed through villi present in the small intestine into the bloodstream
• Undigested waste is stored in the large intestine and expelled through the anus

5.3 Respiration

• Respiration is the process in which the energy stored in food (glucose) is released for carrying out life processes
• The breakdown of glucose first occurs in the cytoplasm to form a three-carbon compound called pyruvate
• Pyruvate is then further broken down in different ways depending on the availability of oxygen
• In the presence of oxygen (aerobic respiration), pyruvate is broken down in the mitochondria to form carbon dioxide (CO₂), water (H₂O), and a large amount of energy (ATP)
• In the absence of oxygen (anaerobic respiration), pyruvate is converted into lactic acid in muscle cells, causing cramps
• In organisms like yeast, anaerobic respiration produces ethanol and carbon dioxide
• Aerobic respiration releases more energy compared to anaerobic respiration
• The energy released during respiration is used for growth, repair, movement, and other life activities

5.4 Transportation

• Transportation is the process by which food, oxygen, water, hormones, and waste products are moved from one part of the body to another
• In multicellular organisms, specialised systems are required for efficient transport because diffusion alone is insufficient
• In animals, transportation is carried out by the circulatory system
• In plants, transportation occurs through specialised tissues called xylem and phloem
• The transport system ensures that all cells receive necessary substances for energy production and growth
• It also helps in removal of metabolic wastes, maintaining internal balance
• Efficient transportation is essential for survival and proper functioning of complex organisms

5.4.1 Transportation in Human Beings

• Transportation in human beings is carried out by the circulatory system, which consists of the heart, blood, and blood vessels
• The heart is a muscular organ that pumps blood throughout the body and has four chambers – two atria and two ventricles
• Humans have double circulation, where blood passes through the heart twice in one complete cycle
• Oxygenated blood from the lungs enters the left side of the heart and is pumped to the body, while deoxygenated blood returns to the right side of the heart
• Arteries carry blood away from the heart, veins carry blood towards the heart, and capillaries allow exchange of materials
• Blood contains plasma, red blood cells (RBCs) for oxygen transport, white blood cells (WBCs) for immunity, and platelets for clotting
• The protein haemoglobin present in RBCs binds with oxygen for transport

5.4.2 Transportation in Plants

• Transportation in plants is carried out by specialised tissues called xylem and phloem
• Xylem transports water and minerals from the roots to different parts of the plant
• The upward movement of water in plants occurs due to transpiration pull, root pressure, and cohesion-adhesion forces
• Phloem transports prepared food (glucose) from leaves to other parts of the plant
• The transport of food through phloem is called translocation
• Translocation requires energy (ATP) and can occur in both upward and downward directions
• Efficient transport ensures proper growth, development, and survival of plants

5.5 Excretion

• Excretion is the process of removal of metabolic waste products from the body
• Waste substances such as carbon dioxide, urea, excess salts, and water are produced during life processes
• Accumulation of waste products in the body can be toxic and harmful
• Different organisms have developed specialised excretory systems to remove wastes
• In humans, excretion is mainly carried out by the kidneys
• In plants, waste products are removed through various methods such as transpiration and storage in leaves
• Proper excretion helps maintain internal balance (homeostasis) in living organisms

5.5.1 Excretion in Human Beings

• In human beings, excretion is carried out by the excretory system, which includes the kidneys, ureters, urinary bladder, and urethra
• The kidneys filter blood to remove nitrogenous wastes such as urea, along with excess water and salts
• The basic structural and functional unit of the kidney is the nephron
• Each nephron consists of a glomerulus and a long tubular part where filtration and reabsorption occur
• The process of urine formation involves filtration, reabsorption, and secretion
• The waste fluid formed is called urine, which is stored in the urinary bladder before being expelled
• The kidneys help in maintaining the balance of water, salts, and pH in the body

5.5.2 Excretion in Plants

• Plants do not have a specialised excretory system; waste products are removed through diffusion and transpiration
• Gaseous wastes such as oxygen and carbon dioxide are exchanged through stomata and lenticels
• Excess water is removed by the process of transpiration
• Some waste products are stored in leaves, bark, and old tissues, which are later shed
• Certain wastes are converted into harmless substances and stored in the form of resins, gums, and latex
• Some waste substances are secreted into the surrounding soil through roots
• These methods help plants maintain internal balance without a specialised excretory organ

Exam Oriented Facts

• Life processes include nutrition, respiration, transportation, and excretion
• Photosynthesis equation: 6CO₂ + 12H₂O → C₆H₁₂O₆ + 6O₂ + 6H₂O (in presence of sunlight and chlorophyll)
• Chloroplast is the site of photosynthesis
• Autotrophs prepare their own food; heterotrophs depend on others
• Types of heterotrophic nutrition: saprophytic, parasitic, holozoic
• In Amoeba, food is taken by pseudopodia and digested in food vacuole
• Human digestion begins in the mouth with salivary amylase
• Hydrochloric acid (HCl) is present in the stomach
• Villi in small intestine increase surface area for absorption
• Respiration equation (aerobic): C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy (ATP)
• Mitochondria are called the powerhouse of the cell
• Anaerobic respiration in muscles produces lactic acid
• Anaerobic respiration in yeast produces ethanol and CO₂
• ATP (Adenosine Triphosphate) is the energy currency of the cell
• Human heart has four chambers – two atria and two ventricles
• Humans show double circulation
• Haemoglobin carries oxygen in blood
• Blood vessels: Arteries (away from heart), Veins (towards heart), Capillaries (exchange)
• Plant transport tissues: Xylem (water & minerals), Phloem (food)
• Food transport in plants is called translocation
• Human excretory system: Kidneys, ureters, urinary bladder, urethra
• Structural unit of kidney: Nephron
• Urine formation steps: Filtration, Reabsorption, Secretion
• Plants remove wastes through transpiration, diffusion, and storage in leaves
• Plant wastes include resins, gums, and latex

Understanding NCERT Class 10 Science Chapter 5 – Life Processes strengthens conceptual clarity in biology and prepares students for advanced studies.

NCERT Class 10 Science Chapter 5 connects directly with human physiology, metabolism, and environmental biology topics in competitive exams.

Continue reading NCERT Class 10 Science Chapter 6 – Control and Coordination to understand nervous and hormonal regulation.

FAQs

Q1. What are life processes?
Nutrition, respiration, transportation, and excretion.

Q2. Where does aerobic respiration occur?
In the mitochondria.

Q3. What is double circulation?
Blood passes through the heart twice in one complete cycle.

Q4. What is the functional unit of kidney?
Nephron.

Q5. Why is Chapter 5 important for exams?
It builds the base for human physiology and plant transport systems.

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