Revision Notes: Class 10 Science Chapter 5 Life Processes

A fast, one-glance recap of Class 10 Science Chapter 5 (Life Processes) — for the full explanations, see the Solutions. These Class 10 Science Chapter 5 notes are ideal for quick revision just before exams.

Last Updated: October 24, 2026

Common Mistakes Students Make in Life Processes

Why This Chapter Matters

Life Processes is one of the standard chapters in the CBSE/NCERT Class 10 Science syllabus and questions from it appear regularly in board exams, in formats ranging from 1-mark objective questions to longer 3-5 mark descriptive or numerical questions. Because the concepts here often build on earlier chapters (and feed into later ones), a solid grip on this chapter also makes the rest of the Science syllabus easier to follow.

Revision Notes: Life Processes

• Life processes: nutrition, respiration, transportation, excretion — basic processes needed to maintain the body
• Autotrophic nutrition: organism makes its own food (e.g. green plants) — needs CO₂, water, sunlight, chlorophyll; releases O₂ as by-product
• Heterotrophic nutrition: organism depends on others for food (e.g. humans, Amoeba)
• Human digestion path: mouth (salivary amylase) → stomach (HCl + pepsin) → small intestine (bile emulsifies fat; pancreatic + intestinal enzymes; villi absorb nutrients) → large intestine (water absorption)
• Aerobic respiration: needs O₂, occurs in mitochondria, glucose fully broken down → more energy
• Anaerobic respiration: no O₂ needed, occurs in cytoplasm, glucose partially broken down (ethanol+CO₂ in yeast, or lactic acid in muscle) → less energy
• Human respiratory path: nose → trachea → bronchi → bronchioles → alveoli (gas exchange: huge surface area, thin walls, rich blood supply)
• Double circulation: blood passes through the heart twice per cycle (pulmonary + systemic) — keeps oxygenated/deoxygenated blood separate, needed for high, constant energy demand
• Excretory system: kidneys (basic unit: nephron) filter blood → urine → ureters → bladder → urethra
• Xylem: water/minerals, one-way (upward), dead cells, passive (transpiration pull)
• Phloem: food, both directions (source to sink), living cells, active transport (uses ATP)
• Key comparison: alveoli (gas exchange) vs nephrons (blood filtration) — both maximise surface area via millions of thin-walled, richly-vascularised units

See also: Extra Questions (HOTS) | Formulas Handbook

How to Use These Notes

These revision notes are meant for quick recall in the last few days before an exam or unit test — they are not a substitute for first reading the full chapter and working through examples in the NCERT textbook. A good routine is: read the chapter once, solve the in-text and end-of-chapter questions using the linked Solutions, then come back to this page a day or two before the exam to refresh the key definitions and formulas without re-reading the whole chapter.

Quick visual: a worked diagram from the full Solutions page, for reference.

Frequently Asked Questions

What is the difference between autotrophic and heterotrophic nutrition?
Autotrophic nutrition means an organism makes its own food (like plants via photosynthesis); heterotrophic nutrition means an organism depends on other organisms for food (like animals and fungi) — this distinction opens the chapter’s discussion of nutrition across different life forms.

What are the main steps of human digestion covered in this chapter?
Ingestion, digestion (mechanical and chemical breakdown by enzymes in the mouth, stomach, and small intestine), absorption of nutrients (mainly in the small intestine), and egestion of undigested waste — each step and its associated organs/enzymes is tested in detail.

What to Revise First (and Last) in This Chapter

Written by Satish

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