Chapter 5: Life Processes
Simple, exam-focused CBSE Class 10 Science notes — star topics, concepts, common mistakes, and previous year question patterns, all on one page.
Chapter 5: Life Processes
⭐ Star Topics / Most Important
- Nutrition (autotrophic vs heterotrophic)
- Human digestive system
- Respiration (aerobic vs anaerobic)
- Transportation — heart and double circulation
- Excretion — nephron structure
Detailed Chapter Notes
Life processes are the basic functions keeping an organism alive — nutrition, respiration, transportation, and excretion are the big four for boards.
Nutrition: autotrophs make their own food via photosynthesis (6CO2 + 12H2O → C6H12O6 + 6O2 + 6H2O in sunlight/chlorophyll). Heterotrophs depend on others (holozoic, saprophytic, parasitic).
Digestion: mouth → oesophagus → stomach → small intestine → large intestine. Saliva has amylase (starch → sugar). Stomach's HCl kills bacteria and activates pepsin (protein digestion). Small intestine: bile emulsifies fats, pancreatic juice gives trypsin and lipase. Absorption happens through villi.
Respiration: aerobic (in mitochondria, glucose + O2 → CO2 + water + lots of energy) vs anaerobic (yeast fermentation → alcohol + CO2; muscles during exercise → lactic acid, causing cramps, much less energy released).
Transportation: heart has 4 chambers (2 atria, 2 ventricles). Double circulation keeps oxygenated and deoxygenated blood almost completely separate, allowing efficient, constant body temperature.
Excretion: the kidney's functional unit is the nephron. Blood filters at the glomerulus, useful substances reabsorb in tubules, waste (urea, excess salts, water) becomes urine → ureters → bladder → urethra.
Students confuse "breathing" (physical intake/outtake of air) with "respiration" (chemical breakdown of glucose to release energy at cellular level). Also, arteries carry blood away from the heart (usually oxygenated, except pulmonary artery) and veins carry blood towards the heart (usually deoxygenated, except pulmonary vein) — this exception is a favourite trick question.
Search on YouTube: Life Processes Class 10 one shot NCERT for a visual walkthrough of this chapter.
- Why is the small intestine longer in herbivores than in carnivores? (2 marks)
- Draw a labelled diagram of the human excretory system (3 marks)
- Explain double circulation and why it is necessary in humans (3 marks)
- Differentiate between aerobic and anaerobic respiration (2 marks)
- What is the role of saliva in the digestion of food? (2 marks)