Life Processes — Nutrition, Respiration, Transport and Excretion
A friendly Class 10 walkthrough of the four life processes: how organisms get nutrition, release energy through respiration, transport materials in humans and plants, and remove wastes by excretion.
By the PadhoDost Team · 📖 8 min read · Updated 4 August 2026
Part of Class 10 (CBSE) prep🧠 A living city
Think of your body as a busy city. Food trucks bring in supplies (nutrition), power stations burn fuel for energy (respiration), a road-and-pipe network delivers goods everywhere (transportation), and garbage vans carry away the waste (excretion). A city stops working if any one service fails — and so does a living body. These four services are the life processes.
Life processes are the basic functions that every living organism must carry out to stay alive and maintain itself, even while resting. The main ones in the Class 10 syllabus are nutrition, respiration, transportation and excretion. Together they keep the body's cells fed, energised, connected and clean.
1. Nutrition — getting food
Nutrition is how organisms obtain and use food for energy and growth. Autotrophs (green plants) make their own food by photosynthesis; heterotrophs (animals, fungi) take food from outside. In humans, digestion breaks large food molecules into small absorbable ones with the help of enzymes.
2. Respiration — releasing energy
Respiration breaks down glucose to release energy stored as ATP. Aerobic respiration (with oxygen, in the mitochondria) releases a lot of energy; anaerobic respiration (without oxygen) releases much less. In our muscles during heavy exercise, glucose turns into lactic acid, which causes cramps.
| Feature | Aerobic respiration | Anaerobic respiration |
|---|---|---|
| Oxygen | Required | Not required |
| End products | CO2 + water | Lactic acid (muscles) or ethanol + CO2 (yeast) |
| Energy released | Large amount | Small amount |
| Site | Cytoplasm + mitochondria | Cytoplasm only |
3. Transportation — the delivery network
In humans, blood carries oxygen, food and wastes, pumped by a four-chambered heart. Our circulation is a double circulation: blood passes through the heart twice in one full cycle, keeping oxygenated and deoxygenated blood separate. In plants, xylem carries water and minerals upward, while phloem transports food (translocation) in both directions.
4. Excretion — removing waste
Excretion removes harmful nitrogenous wastes like urea. In humans the kidneys filter blood; their functional unit is the nephron, where useful substances are reabsorbed and urine is formed. Plants excrete more simply — through stomata, by shedding leaves, or storing wastes as resins and gums.
📝 Follow one glucose molecule
You eat a chapati; starch is digested to glucose in the small intestine.
Glucose is absorbed into the blood and carried to body cells.
Inside a cell's mitochondria, glucose combines with oxygen (aerobic respiration).
Energy is released as ATP; the cell uses it to work.
Waste CO2 leaves via blood to the lungs and is breathed out; nitrogenous waste (urea) is filtered by kidneys.
Quick revision
- ✓Autotrophic nutrition = self-made food (photosynthesis); heterotrophic = food from outside.
- ✓Aerobic respiration needs oxygen and gives more energy than anaerobic.
- ✓Humans have a four-chambered heart and double circulation.
- ✓Xylem transports water/minerals upward; phloem transports food both ways.
- ✓The nephron is the functional unit of the kidney; urea is the main nitrogenous waste.
⚡ Quick check
During vigorous exercise, why do our leg muscles sometimes cramp?
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