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Class 10 Science Chapter 1: Life Processes
Complete CBSE Notes (Detailed Revision Edition)
Introduction to Life Processes
Life processes are the basic activities that help living organisms stay alive. Every organism needs food, energy, transportation of materials and removal of waste products. The four major life processes are Nutrition, Respiration, Transportation and Excretion. Living organisms require continuous energy for growth, repair and maintenance of body functions.
Nutrition
Nutrition is the process by which organisms obtain food and utilize it. It provides energy, helps growth and repairs damaged tissues.
Types of Nutrition:
- Autotrophic Nutrition
- Heterotrophic Nutrition
Autotrophic Nutrition: Green plants prepare food by photosynthesis. Requirements are sunlight, chlorophyll, carbon dioxide and water.
Photosynthesis: Carbon dioxide + Water → Glucose + Oxygen
Importance:
- Produces food.
- Releases oxygen.
- Maintains balance of gases.
Stomata: Tiny pores on leaves that help in gas exchange and transpiration.
Heterotrophic Nutrition:
- Holozoic (Human, Amoeba)
- Saprophytic (Fungi)
- Parasitic (Cuscuta)
Nutrition in Human Beings
Digestive System: Mouth → Oesophagus → Stomach → Small Intestine → Large Intestine → Rectum → Anus
Mouth:
- Teeth chew food.
- Saliva contains salivary amylase.
Stomach:
- Hydrochloric acid kills germs.
- Pepsin digests proteins.
- Mucus protects stomach lining.
Small Intestine:
- Bile juice emulsifies fats.
- Pancreatic enzymes digest food.
- Villi absorb nutrients.
Large Intestine:
- Absorbs water.
- Stores waste material.
Functions of Digestive System:
- Digestion
- Absorption
- Assimilation
- Egestion
Respiration
Respiration is the process of releasing energy from food.
Types:
- Aerobic Respiration
- Anaerobic Respiration
Aerobic Respiration: Occurs in presence of oxygen. Produces more energy.
Anaerobic Respiration: Occurs without oxygen. Produces less energy.
In yeast: Glucose → Ethanol + Carbon dioxide + Energy
Importance:
- Releases energy.
- Supports body activities.
- Helps growth and repair.
Transportation in Plants
Plants transport water, minerals and food using vascular tissues.
Xylem:
- Carries water and minerals from roots to leaves.
Phloem:
- Carries prepared food from leaves to all parts.
Transpiration: Loss of water through stomata.
Advantages:
- Cooling effect.
- Helps upward movement of water.
- Maintains water balance.
Excretion
Excretion is removal of harmful metabolic wastes.
Human Excretory System:
- Kidneys
- Ureters
- Urinary Bladder
- Urethra
Nephron: Structural and functional unit of kidney.
Urine Formation:
- Filtration
- Reabsorption
- Secretion
Artificial Kidney (Dialysis): Used when kidneys fail to function properly.
Excretion in Plants:
- Waste stored in leaves and bark.
- Gases removed through stomata.
- Excess water removed by transpiration.
Important NCERT Questions and Revision
- Why are life processes important?
- Define photosynthesis.
- What is the function of stomata?
- Differentiate between aerobic and anaerobic respiration.
- What are alveoli?
- Name the components of blood.
- Explain double circulation.
- Differentiate between xylem and phloem.
- What is transpiration?
- What is a nephron?
Important Keywords: Life Processes, Nutrition, Photosynthesis, Stomata, Respiration, Alveoli, Blood, Heart, Xylem, Phloem, Transpiration, Excretion, Nephron, Dialysis.
