Class 10th Science: Life Process (Chapter 6 Part-I) Notes

Key Topics:

• Introduction to Life Processes
• Modes of Nutrition
• Autotrophic Nutrition
• Heterotrophic Nutrition
• Nutrition in Human Beings
• Human Digestive System

Introduction

• All living organisms perform essential life processes like growth, excretion, respiration, and circulation.
• Life Processes: Maintain life and include respiration, digestion, etc.

Modes of Nutrition

Nutrition in Plants

• Plants are autotrophs.
  • Produce their own food.
  • Consume animals for their food.

Nutrition in Animals

• Animals are heterotrophs.
  • Depend on plants or other animals for food.

Autotrophic Nutrition

• Involves using inorganic materials (e.g., CO₂, water) to create organic food via photosynthesis.
• Photosynthesis: Process of converting CO₂ and H₂O into carbohydrates using chlorophyll and sunlight.
  • Equation for Photosynthesis:

Raw Materials for Photosynthesis

• Sunlight: Absorbed by chlorophyll.
• Chlorophyll: Essential for absorbing sunlight.
• CO₂: Enter through stomata; O₂ released as by-product.
• Water: Along with dissolved minerals absorbed by roots.

Site of Photosynthesis

• Takes place in chloroplasts, which contain chlorophyll.

Main Events of Photosynthesis

• Absorption of light by chlorophyll.
• Conversion of light energy into chemical energy; splitting of water into hydrogen and oxygen.
• CO₂ reduction to form carbohydrates.

Stomata

• Tiny pores on the leaf surface.

Functions of Stomata

• Gas exchange: O₂ and CO₂.
• Transpiration: Water vapor loss.

Heterotrophic Nutrition

• Organisms can't synthesize their own food; rely on autotrophs.
• Types of Heterotrophic Nutrition:
  • Holozoic Nutrition: Solid food intake (e.g., Amoeba, animals).
  • Saprophytic Nutrition: Feeding on decaying matter (e.g., Fungi).
  • Parasitic Nutrition: Nutrition from host organisms (e.g., Ticks, Cuscuta).

How Organisms Obtain Food

• Unicellular Organisms: Absorb food across entire surface (e.g., Amoeba, Paramaecium).
  • Paramaecium: Uses cilia for food intake.

Nutrition in Human Beings

• The alimentary canal is a long tube from mouth to anus, specialized for different digestive functions.

Human Digestive System

• Mouth: Food intake.
• Teeth: Chew and grind food.
• Tongue: Rolls, tastes, and swallows food.
• Salivary Glands: Produce saliva; saliva converts starch into glucose.
• Oesophagus: Transports food via peristalsis.
• Stomach: Secretes gastric juices.
• Small Intestine: Completes digestion of carbohydrates, proteins, fats.
  • Villi: Absorb nutrients into blood.
  • Pancreas: Secretes digestive enzymes (e.g., trypsin, lipase).
  • Bile Salts: Break down fat globules.
• Large Intestine: Absorbs water; expels waste.

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For further reading, see Part 2 Life Process Notes.

Return to Class 10 Science Notes.