Comprehensive study guide on essential life processes: nutrition, respiration, transportation, and excretion. Learn how organisms obtain energy, grow, repair cells, and survive in their environment.
Life processes are the basic activities necessary to maintain life in living organisms. These processes help organisms to obtain energy, grow, repair cells, and survive in their environment.
Nutrition is the process by which organisms obtain food and utilize it for energy, growth, and maintenance.
Organisms prepare their own food.
Carbon dioxide + Water → Glucose + Oxygen
Organisms depend on others for food.
| Type | Description | Examples |
|---|---|---|
| Holozoic | Ingestion of complex organic matter | Humans, animals |
| Saprophytic | Feeding on dead and decaying matter | Fungi, bacteria |
| Parasitic | Feeding on living host organisms | Tapeworm, lice |
The human digestive system breaks complex food into simple soluble substances.
| Organ | Function | Enzymes/Secretions |
|---|---|---|
| Mouth | Chewing and mixing with saliva | Salivary amylase |
| Stomach | Protein digestion with gastric juice | Pepsin, HCl |
| Small Intestine | Complete digestion and absorption | Pancreatic enzymes, bile |
| Large Intestine | Water absorption | --- |
Respiration is the process of releasing energy from food.
Aerobic Respiration Formula: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy (38 ATP)
Anaerobic Respiration (in yeast): C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂ + Energy (2 ATP)
Gas exchange occurs in alveoli - tiny air sacs with rich blood supply.
Transportation involves movement of substances like food, oxygen, hormones, and waste within the body.
| Tissue | Function | Substances Transported |
|---|---|---|
| Xylem | Transports water and minerals | Water, minerals (upward movement) |
| Phloem | Transports food | Glucose, amino acids (bidirectional) |
Excretion is the process of removal of waste materials from the body.