Life Processes Class 10 Notes (CBSE) – Short & Easy Revision + PDF

Life Processes Class 10 Notes are prepared strictly from your NCERT books of class 10 science chapter 5.

So, you can relay for your school as well as board exams.

The PDF download link is at the end of the short notes. But first, read the short notes thoroughly. The notes are more engaging and interactive.

Happy learning!

Before you rush to memorise the short notes, may I request you to please read the Explanation of life processes, so that you can understand the chapter well.

If we understand something, then it becomes very easy to remember it.

Introduction: Life Processes

WHAT ARE LIFE PROCESSES?

These processes are essential for the survival and maintenance of living organisms.

Specialised Systems in Organisms

Nutrition

Modes of Nutrition

Autotrophic Nutrition

Photosynthesis Process

• Note: Steps may not occur immediately one after another (e.g., desert plants store intermediates at night).

Essential Components for Photosynthesis

Heterotrophic Nutrition

• Organisms obtain food from external sources (plants, animals, or organic matter).
• Varies based on environment, food type, and availability.
• Food source determines how food is accessed.

Types of Heterotrophic Nutrition

How Organisms Obtain Nutrition

• Food type and acquisition method differ across organisms.
• Varies based on organism complexity.
  • Simple organisms: Use the entire surface for food intake.
  • Complex organisms: Specialised parts for digestion.

Nutrition in Single-Celled Organisms

1. Amoeba

Uses temporary finger-like extensions (pseudopodia).

• Process:
  • Pseudopodia surround food, forming a food vacuole.
  • Complex substances are broken down into simpler ones inside the vacuole.
  • Simpler substances diffuse into the cytoplasm.
  • Undigested material is expelled from the cell surface.
• Key Feature: No fixed food intake spot.

2. Paramoecium

Food is taken in at a specific spot.

• Process:
  • Cilia (hair-like structures) move food to a fixed spot.
  • Food is ingested and digested within the cell.

Nutrition in Human Beings

• Alimentary Canal: A long tube from the mouth to the anus with specialized regions.
• Function: Breaks down complex food into small, absorbable molecules.
• Key Processes: Digestion, absorption, and waste elimination.

Digestive Process

1. Mouth

Food is crushed by teeth and mixed with saliva.

• Saliva:
  • Secreted by salivary glands.
  • Contains salivary amylase (enzyme) → Breaks down starch into simple sugars.
• Tongue: Mixes food with saliva, aids chewing.
• Movement: Food moved to the esophagus via peristalsis (rhythmic muscle contractions).

2. Esophagus

• Role: Transports food to the stomach via peristaltic movements.
• Structure: The food pipe connecting the mouth to the stomach.

3. Stomach

• Action: Expands to hold food, mixes with digestive juices.
• Gastric Glands secrete:
  • Hydrochloric acid (HCl): Creates an acidic medium, aids pepsin.
  • Pepsin: Digests proteins.
  • Mucus: Protects the stomach lining from acid.
• Exit: Regulated by the sphincter muscle, releasing food to the small intestine.
• Note: Acidity issues may relate to excess HCl.

4. Small Intestine

• Structure: Longest part, coiled for compact fit.
  • Length varies: Longer in herbivores (e.g., for cellulose digestion), shorter in carnivores.
• Function: Complete digestion of carbohydrates, proteins, and fats.
• Secretions:
  • Liver: Produces bile → Emulsifies fats (breaks into smaller globules).
  • Pancreas: Secretes pancreatic juice with:
    • Trypsin: Digests proteins.
    • Lipase: Breaks down emulsified fats.
  • Intestinal glands: Secrete intestinal juice → Converts:
    • Proteins → Amino acids.
    • Carbohydrates → Glucose.
    • Fats → Fatty acids, glycerol.
• Absorption:
  • Villi: Finger-like projections increase surface area.
  • Rich in blood vessels → Transport nutrients to body cells for energy, tissue building, repair.

5. Large Intestine

• Role: Absorbs water from unabsorbed food.
• Waste: Remaining material expelled via the anus, regulated by the anal sphincter.

Respiration

Breaks down food (glucose) to release energy for life processes.

• Glucose (6-carbon) → Pyruvate (3-carbon) in cytoplasm.
• ATP (adenosine triphosphate) fuels cellular activities.
• Types:
  • Aerobic Respiration: Uses oxygen, occurs in mitochondria, produces CO₂, water, and high energy.
  • Anaerobic Respiration: No oxygen, produces less energy (e.g., ethanol in yeast, lactic acid in muscles).

Respiration Pathways

• Step 1: Glucose → Pyruvate (cytoplasm, all organisms).
• Aerobic Pathway:
  • Pyruvate → CO₂ + H₂O (mitochondria, high energy).
• Anaerobic Pathways:
  • Yeast: Pyruvate → Ethanol + CO₂ (fermentation).
  • Muscles (low oxygen): Pyruvate → Lactic acid (causes cramps).
• ATP: Energy is stored in ATP and used for cellular reactions.

Gas Exchange in Organisms

Respiration in Humans

Pathway

• Nostrils: Air filtered by hairs and mucus.
• Throat: Supported by cartilage rings to prevent collapse.
• Lungs: Air reaches alveoli via smaller tubes.
• Alveoli: Balloon-like structures for gas exchange.
  • Rich in blood vessels.
  • O₂ is absorbed into the blood, and CO₂ is released into the alveoli.
• Breathing Mechanism:
  • Inhalation: Ribs lift, diaphragm flattens, chest cavity expands → Air sucked in.
  • Exhalation: CO₂ is released, and residual air remains for continuous gas exchange.

Oxygen Transport

• Respiratory Pigment: Haemoglobin (in red blood cells).
• High affinity for O₂, carries it to tissues.
• CO₂ Transport: Mostly dissolved in blood (more soluble than O₂).

Transportation in Human Beings

• Role of Blood: Transports food, oxygen, carbon dioxide, nitrogenous wastes, and salts.
• Blood Composition:
  • Plasma: Fluid medium, transports food, carbon dioxide, and nitrogenous wastes in dissolved form.
  • Red Blood Corpuscles: Carry oxygen via haemoglobin.
  • Platelets: Aid in clotting to minimize blood loss.
• System Components:
  • Heart: A pumping organ that pushes blood.
  • Blood Vessels: A network of tubes to reach all tissues.
  • Lymph: Fluid for fat transport and excess fluid drainage.

The Heart

• Structure: Muscular organ, the size of a fist, with four chambers.
• Chambers:
  • Left Atrium: Receives oxygen-rich blood from lungs.
  • Left Ventricle: Pumps oxygen-rich blood to the body.
  • Right Atrium: Receives deoxygenated blood from the body.
  • Right Ventricle: Pumps de-oxygenated blood to lungs.
• Function:
  • Prevents mixing of oxygen-rich and deoxygenated blood.
  • Valves: Ensure blood does not flow backwards during contraction.
  • Ventricles have thicker muscular walls than atria for pumping under pressure.
• Circulation:
  • Double Circulation: Blood passes through the heart twice per cycle (lungs → heart → body → heart).

Blood Vessels

• Arteries:
  • Carry blood away from the heart to various organs.
  • Thick, elastic walls to withstand high pressure.
• Veins:
  • Collect blood from organs, bring it back to the heart.
  • Thin walls contain valves to ensure one-directional flow.
• Capillaries:
  • Smallest vessels, one-cell-thick walls.
  • Enable exchange of material (oxygen, carbon dioxide, nutrients) between blood and surrounding cells.

Gas Exchange in Lungs

• Process: Oxygen enters the blood, and carbon dioxide is released in the alveoli.
• Pathway:
  • Oxygen-rich blood: Lungs → Left atrium → Left ventricle → Body.
  • De-oxygenated blood: Body → Right atrium → Right ventricle → Lungs.
• Efficiency: Separation of oxygen-rich and de-oxygenated blood supports high energy needs (e.g., birds, mammals).
• Comparison:
  • Amphibians/Reptiles: Three-chambered hearts, tolerate some mixing of oxygenated and de-oxygenated blood.
  • Fish: Two-chambered hearts, single circulation (blood passes through the heart once).

Maintenance by Platelets

• Role: Minimize blood loss by forming clots at points of injury.
• Mechanism: Platelet cells circulate, plug leaks, and maintain pressure in the pumping system.

Lymph

• Definition: Tissue fluid (lymph) is formed when plasma, proteins, and blood cells escape through pores in capillary walls into intercellular spaces.
• Composition: Colourless, similar to plasma, but contains less protein.
• Functions:
  • Carries digested and absorbed fat from the intestine.
  • Drains excess fluid from intercellular spaces back into the blood.
• Pathway:
  • Lymph drains into lymphatic capillaries.
  • Lymphatic capillaries join to form large lymph vessels.
  • Large lymph vessels open into larger veins.

Transportation in Plants

• Purpose: Moves energy (from leaves) and raw materials (from roots) to support plant functions.
• Raw Materials: Nitrogen, phosphorus, minerals from soil; CO₂ for photosynthesis.
• Source: Soil (via roots), air (via leaves).
• Need for Transport: Diffusion insufficient for large plants; specialized systems required.
• Energy Needs: Low due to immobile nature and dead cells in tissues.
• Transport Systems:
  • Xylem: Moves water and minerals from roots.
  • Phloem: Transports photosynthesis products (e.g., sucrose) and other substances.

Transport of Water

• System: Xylem vessels and tracheids form a continuous water-conducting channel (roots → stems → leaves).
• Mechanism:
  • Root Uptake: Root cells actively take up ions, creating a concentration gradient.
  • Water moves into roots to balance ion concentration, forming a water column in xylem.
  • Root Pressure: Pushes water upward (more significant at night).
• Transpiration:
  • Loss of water vapor from aerial parts (via stomata).
  • Creates suction (transpiration pull) to draw water from xylem in roots to leaves.
  • Major driving force during the day when stomata are open.
• Functions:
  • Transports water and dissolved minerals to leaves.
  • Regulates plant temperature.

Transport of Food and Other Substances

• System: Phloem (sieve tubes and companion cells).
• Process: Translocation – Movement of soluble photosynthesis products (e.g., sucrose), amino acids, and other substances.
• Mechanism:
  • Uses ATP energy to transfer materials (e.g., sucrose) into phloem.
  • Increases osmotic pressure, causing water to enter the phloem.
  • Pressure drives materials to areas of lower pressure (e.g., storage organs, growing parts).
• Direction: Upward and downward, based on plant needs (e.g., sugar from roots to buds in spring).
• Destinations: Storage organs (roots, fruits, seeds), growing organs.

Excretion

• Definition: Biological process of removing harmful metabolic wastes from the body.
• Types of Wastes:
  • Gaseous: CO₂ (via respiration/photosynthesis).
  • Nitrogenous: Urea, uric acid (via excretory system).
• Methods:
  • Unicellular organisms: Simple diffusion across the body surface into the surrounding water.
• Multicellular organisms: Specialized organs for excretion.

Excretory System in Human Beings

• Components:
  • Kidneys: Pair, located in the abdomen on either side of the backbone.
  • Ureters: Tubes carrying urine from the kidneys to the bladder.
  • Urinary Bladder: Stores urine until release.
  • Urethra: Releases urine from the bladder.
  • Function: Filters nitrogenous wastes (urea, uric acid) from blood.

Urine Formation

• Process:
• Filtration: Occurs in nephrons (basic filtration units in the kidneys).
  • Each nephron has a Bowman’s capsule (cup-shaped) with a cluster of thin-walled blood capillaries.
  • Blood is filtered to form the initial filtrate (contains waste, water, glucose, amino acids, salts).
• Selective Reabsorption: As filtrate flows through the nephron tubes:
  • Glucose, amino acids, salts, and most water are reabsorbed into the blood.
  • The amount of water reabsorbed depends on the body’s water and waste levels.
• Urine Collection: Final urine (waste + some water) enters the ureters → urinary bladder.
• Storage and Release:
  • Urine is stored in the muscular urinary bladder.
  • Bladder expansion triggers the urge to urinate via the urethra.
  • Urination under nervous control, allowing voluntary regulation.

Excretion in Plants

• Definition: Removal of metabolic waste products from plant tissues.
• Key Difference: Unlike animals, plants lack specialized excretory organs.
• Wastes:
  • Gaseous: Oxygen (from photosynthesis), CO₂ (from respiration).
  • Liquid: Excess water.
  • Other: Metabolic byproducts (resins, gums, etc.).
• Strategies: Utilize dead tissues, shedding parts, and diffusion into the surroundings.

Excretion Mechanisms

• Gaseous Wastes:
  • Oxygen: Waste from photosynthesis, released via stomata.
  • Carbon Dioxide: Waste from respiration, released via stomata.
• Excess Water:
  • Removed through transpiration (evaporation of water vapor from aerial parts, mainly leaves).
• Other Metabolic Wastes:
  • Stored in cellular vacuoles (compartments within cells).
  • Accumulated in dead cells (e.g., old xylem) as resins or gums.
  • Stored in leaves that fall off, removing wastes from the plant.
  • Excreted into the soil around roots.

Conclusion: Life Processes Short Notes Class 10

If you’ve read this far, you know the Life Processes chapter is long and full of technical terms.

But,

With the right mindset and zeal, you can master it. Keep revising from your NCERT book and our website. We’ll add more study tools to help you study less and score more.

Please share with your friends!

Newsletter Signup Form

Please enable JavaScript in your browser to complete this form.

Email Name

Name *

First

Last

Email *

Submit