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Class 10 Science - Chapter 6: Life Processes

Jun 27, 2024

Class 10 Science - Chapter 6: Life Processes

Introduction

  • Chapter Name: Life Processes
  • Key topic: Processes that maintain body functions and are necessary for survival.
  • Main life processes: Nutrition, Respiration, Transportation, Excretion.

Nutrition

  • Definition: Process by which organisms obtain nutrients from food for energy, building, and tissue repair.
  • Nutrients: Carbohydrates, proteins, vitamins, minerals, etc.
  • Types of Nutrition:
    • Autotrophic Nutrition: Organisms (autotrophs) prepare their own food from inorganic materials (water, CO2) using sunlight (e.g., plants via photosynthesis).
    • Heterotrophic Nutrition: Organisms depend on others for food (e.g., humans depend on plants, animals).
  • Photosynthesis in Plants:
    • Process converting CO2 and water into glucose using chlorophyll and sunlight.
    • Equation: 6 CO2 + 6 H2O -> C6H12O6 + 6 O2 (in presence of chlorophyll and sunlight).
    • Events in Photosynthesis:
      1. Absorption of light energy by chlorophyll.
      2. Conversion of light energy into chemical energy and splitting of water into hydrogen and oxygen.
      3. Reduction of CO2 to carbohydrates.
    • Chloroplast: Organelles containing chlorophyll in plant cells, essential for photosynthesis.
  • Types of Heterotrophic Nutrition:
    • Saprophytic: Obtaining food from dead organic matter (e.g., bacteria, fungi).
    • Parasitic: Living on or inside a host organism, deriving food without killing the host (e.g., mosquitoes, lice).
    • Holozoic: Involves ingestion, digestion, absorption, and assimilation of solid or liquid organic material (e.g., amoeba, humans).
  • Nutrition in Amoeba: Engulfs food particles using pseudopodia, digests in food vacuole, absorbs nutrients, and ejects waste.
  • Nutrition in Human Beings: Complex process involving ingestion, digestion, absorption, assimilation, and excretion.
    • Steps: Mouth -> Esophagus -> Stomach -> Small Intestine -> Large Intestine -> Rectum/Anus.
    • Enzymes involved: Amylase (mouth), Pepsin (stomach), Trypsin, Lipase (small intestine), etc.

Respiration

  • Definition: Process of breaking down food to release energy, including breathing.
  • Stages of Respiration:
    • External Respiration: Breathing and gas exchange (lungs to blood).
    • Internal Respiration: Gas exchange between blood and body cells.
  • Types of Respiration:
    • Aerobic Respiration: Complete breakdown of food with oxygen, releases large energy (38 ATP) (e.g., humans, plants).
    • Anaerobic Respiration: Incomplete breakdown of food without oxygen, releases less energy (2 ATP) (e.g., yeast, bacteria).
    • Fermentation: Anaerobic respiration in microorganisms (e.g., alcoholic fermentation in yeast).
  • Respiration in Plants: Gas exchange via stomata (leaves), lenticels (stems), root hairs (roots).
  • Respiration in Humans: Involves nostrils -> trachea -> bronchi -> bronchioles -> alveoli (gas exchange site).
    • Inhalation & Exhalation: Chest expansion and contraction, diffusion of oxygen into blood, and CO2 out of blood.
    • Hemoglobin: Transports oxygen in blood as oxyhemoglobin.

Transportation

  • Definition: Movement of substances within an organism.
  • Transportation in Humans:
    • Circulatory System: Blood and lymph as transport fluids.
    • Components of Blood: Plasma, RBCs, WBCs, Platelets.
    • Heart: Muscular organ pumping blood through arteries and veins, consists of atria and ventricles, valves, septum.
    • Double Circulation: Blood circulates twice through the heart, involving pulmonary (lungs) and systemic (body) circuits.
    • Blood Vessels:
      • Arteries: Thick, carry oxygenated blood (except pulmonary artery).
      • Veins: Thin, carry deoxygenated blood (except pulmonary vein).
    • Lymph: Colorless fluid, absorbs fats from intestines, removes excess tissue waste.
  • Transportation in Plants: Use of specialized tissues.
    • Xylem: Transports water and minerals from roots to aerial parts, unidirectional, works via transpiration.
    • Phloem: Transports food from leaves to other parts, bidirectional, works via translocation.

Excretion

  • Definition: Removal of harmful nitrogenous wastes from the body.
  • Types of Metabolic Waste: Digestive, respiratory, nitrogenous.
  • Human Excretory System:
    • Organs: Kidneys (filter blood), ureters (transport urine), urinary bladder (stores urine), urethra (expels urine).
    • Kidney Filtration Unit: Nephrons, consists of BowmanтАЩs capsule, HenleтАЩs loop for reabsorption, and ducts for urine collection.
  • Excretion in Plants:
    • Gaseous Waste: O2, CO2 via stomata.
    • Liquid Waste: Water via transpiration.
    • Solid Waste: Stored in leaves, bark, removed by shedding.

I hope this summary helps in revising the chapter. Feel free to reach out for any questions or clarifications.

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