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Life Processes Class 10 Science — Revision Notes

This chapter covers the fundamental processes that maintain life in organisms including nutrition, respiration, and circulation. Students learn how organis

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TL;DR: This chapter covers the fundamental processes that maintain life in organisms including nutrition, respiration, and circulation. Students learn how or…

Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated Jul 23, 2026

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This chapter covers the fundamental processes that maintain life in organisms including nutrition, respiration, and circulation. Students learn how organis

Nutrition

  • Autotrophic nutrition: organisms synthesize own food (plants use photosynthesis)
  • Heterotrophic nutrition: organisms consume other organisms for food
  • Photosynthesis: 6CO2 + 6H2O + light = C6H12O6 + 6O2
  • Chlorophyll in chloroplasts absorbs light energy in leaves

Respiration

  • Aerobic respiration: C6H12O6 + 6O2 = 6CO2 + 6H2O + energy (38 ATP)
  • Occurs in mitochondria releasing large amounts of energy
  • Anaerobic respiration: occurs without oxygen in muscles during exercise
  • Lactic acid fermentation produces lactate causing muscle fatigue

Circulation

  • Heart pumps blood through arteries to body and veins back to heart
  • Pulmonary circulation: heart to lungs and back
  • Systemic circulation: heart to body and back
  • Blood pressure varies: systolic during heart contraction, diastolic during relaxation

Excretion

  • Kidneys filter blood to remove nitrogenous wastes forming urine
  • Urine stored in bladder and eliminated through urethra
  • Lungs excrete carbon dioxide during respiration
  • Skin excretes sweat containing water and salts

Key Terms

  • Photosynthesis: Process where plants convert light energy into chemical energy in glucose
  • ATP: Adenosine triphosphate - energy currency of cells
  • Mitochondria: Powerhouse of cell where aerobic respiration occurs

Frequently Asked Questions

Why do we need respiration?

Respiration breaks down glucose to release energy in the form of ATP which is used for all life processes including movement, growth, and maintenance.

What is the difference between photosynthesis and respiration?

Photosynthesis uses light energy to make glucose, while respiration breaks down glucose to release energy. Photosynthesis occurs in chloroplasts, respiration in mitochondria.

More Class 10 Science Revision Notes

  • Chemical Reactions and Equations
  • Acids Bases and Salts
  • Metals and Non-metals
  • Carbon and its Compounds
  • Control and Coordination
  • How do Organisms Reproduce

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More free resources for this chapter

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