๐ฐ Introduction
All living organisms perform various processes to maintain and sustain life. These processes are called life processes. They include nutrition, respiration, transportation, and excretion.
๐ฝ️ 1. Nutrition
Definition: The process by which organisms take in food and utilize it for energy and growth.
Types of Nutrition:
Autotrophic: Organisms make their own food (e.g., plants).
Heterotrophic: Organisms depend on others for food (e.g., animals).
Autotrophic Nutrition – Photosynthesis:
Equation:
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂Requires sunlight, chlorophyll, carbon dioxide, and water.
Heterotrophic Nutrition:
Holozoic: Ingestion, digestion, absorption, assimilation, egestion.
Saprophytic: Feed on dead and decaying matter.
Parasitic: Live on/in another organism.
๐จ 2. Respiration
Definition: The process of breaking down food to release energy.
Aerobic Respiration: With oxygen.
Glucose + O₂ → CO₂ + H₂O + EnergyAnaerobic Respiration: Without oxygen. Produces less energy.
(e.g., in yeast: glucose → alcohol + CO₂)
In humans: Takes place in mitochondria.
๐ฉธ 3. Transportation
In Plants:
Xylem: Transports water and minerals from roots to leaves.
Phloem: Transports food from leaves to other parts.
In Humans:
Blood: Transports oxygen, nutrients, waste, etc.
Components: RBCs, WBCs, Platelets, Plasma.
Heart: Pumps blood; has 4 chambers.
Blood Vessels: Arteries, veins, capillaries.
Lymph: Transparent fluid for immunity and transport.
๐ฝ 4. Excretion
Definition: Removal of metabolic waste from the body.
In Humans:
Organs: Kidneys, ureters, bladder, urethra.
Nephron: Functional unit of kidney.
In Plants:
Use old leaves and bark to remove waste.
Store waste in vacuoles or excrete through stomata.
✅ Key Points to Remember
Nutrition: Autotrophs vs Heterotrophs.
Respiration: Aerobic (more energy) vs Anaerobic.
Transport system: Xylem & phloem in plants; heart & blood in animals.
Excretion: Kidneys in humans; vacuoles in plants.
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