Question
Compare the processes of nutrition, respiration, transport, and excretion in plants and animals. Why are these called “life processes”?
(CBSE Class 10 — Life Processes)
Life Processes: Plant vs Animal
flowchart TD
A["Life Processes"] --> B["Nutrition"]
A --> C["Respiration"]
A --> D["Transport"]
A --> E["Excretion"]
B --> B1["Plants: Photosynthesis (autotrophic)"]
B --> B2["Animals: Ingestion (heterotrophic)"]
C --> C1["Plants: Through stomata/lenticels"]
C --> C2["Animals: Through lungs/gills/skin"]
D --> D1["Plants: Xylem (water) + Phloem (food)"]
D --> D2["Animals: Blood (heart pumps)"]
E --> E1["Plants: Store waste in leaves, bark"]
E --> E2["Animals: Kidneys filter blood"]Solution — Step by Step
Plants (Autotrophic nutrition): Make their own food through photosynthesis:
This happens in chloroplasts. CO enters through stomata, water through roots.
Animals (Heterotrophic nutrition): Cannot make food — they eat plants or other animals. Digestion breaks complex food into simple molecules: starch → glucose (by amylase), proteins → amino acids (by pepsin, trypsin), fats → fatty acids + glycerol (by lipase).
Both plants and animals respire — they break down glucose to release energy:
Plants exchange gases through stomata (leaves) and lenticels (stems). They respire 24 hours a day (photosynthesis happens only during daytime).
Animals use lungs (land animals), gills (fish), or skin (earthworms). The diaphragm creates pressure differences for breathing in humans.
Plants: Two separate systems — xylem carries water and minerals upward (root to leaf) by transpiration pull, and phloem carries food (sucrose) from leaves to all parts by translocation.
Animals: The circulatory system — heart pumps blood through arteries (oxygenated) and veins (deoxygenated). Humans have a double circulation — blood passes through the heart twice in one complete cycle (pulmonary + systemic).
Plants: No specialised excretory organs. They store waste in vacuoles, shed them in falling leaves, or deposit them as resins and gums in bark.
Animals: Kidneys filter blood, removing urea and excess water as urine. Each kidney has about 1 million nephrons — the functional unit of filtration. The process: filtration → reabsorption → secretion → urine formation.
Why This Works
These are called “life processes” because they are essential for survival — without any one of them, the organism dies. Nutrition provides raw materials, respiration releases energy from those materials, transport distributes substances to all cells, and excretion removes toxic waste. Together, they maintain homeostasis — a stable internal environment.
Alternative Method — Table Summary
| Process | Plants | Animals |
|---|---|---|
| Nutrition | Photosynthesis (autotrophic) | Digestion (heterotrophic) |
| Respiration | Stomata, lenticels | Lungs, gills, skin |
| Transport | Xylem + Phloem | Heart + Blood vessels |
| Excretion | Stored in leaves/bark | Kidneys → urine |
CBSE often asks a 5-mark question combining two life processes (e.g., “Compare nutrition and respiration in plants and animals”). Use a table format — it organises your answer clearly and makes it easy for the examiner to give marks. Always include at least one specific example or equation for each process.
Common Mistake
The most common error: “Plants do not respire, they only photosynthesise.” This is completely wrong. Plants respire 24/7 (they need energy continuously). Photosynthesis happens only during daytime when sunlight is available. During the day, the rate of photosynthesis exceeds respiration, so plants release O overall. At night, they only respire and release CO.