Life Processes
Nutrition, respiration, transportation, and excretion in plants and animals.
Chapter Overview
Life processes — nutrition, respiration, transportation, and excretion — keep organisms alive. Covers autotrophic and heterotrophic nutrition, human digestive, respiratory, circulatory, and excretory systems.
Nutrition
- Autotrophs: photosynthesis (6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂)
- Human digestion: mouth → oesophagus → stomach → small intestine → large intestine
- Enzymes: salivary amylase, pepsin, trypsin, lipase
Respiration
Aerobic
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP
Anaerobic (yeast)
Glucose → Ethanol + CO₂ + ATP
Anaerobic (muscle)
Glucose → Lactic acid + ATP
Transport & Excretion
- Heart: 4 chambers; double circulation
- Nephrons filter blood in kidneys
- Plants: xylem and phloem; transpiration
Solved Examples
Step-by-step solutions — read each step before checking the final answer.
Photosynthesis inputs
Raw materials and products of photosynthesis?
- 1Inputs: CO₂, H₂O, sunlight, chlorophyll
- 2Products: glucose, O₂
Answer
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
Heart function
Which chamber pumps blood to lungs?
- 1Right ventricle pumps deoxygenated blood
- 2To lungs via pulmonary artery
- 3Returns oxygenated to left atrium
Answer
Right ventricle
Key Points to Remember
- ✓ Villi increase absorption surface in small intestine
- ✓ Haemoglobin transports O₂ in RBCs
- ✓ Dialysis for kidney failure
Exam Tips
- • Draw human heart labelled
- • Distinguish aerobic vs anaerobic respiration
- • Know path of food and air
Practice MCQs — Life Processes
Test your understanding with topic-wise multiple choice questions. Explanations appear after each answer.
Site of complete digestion and absorption: