Class 10 Science Chapter 5 (formerly Chapter 6 before rationalisation), Life Processes, is the opening biology chapter of the NCERT Class 10 Science book (2026-27). It examines the four core maintenance processes needed to sustain living organisms: nutrition, respiration, transportation and excretion in both plants and humans.
What Class 10 Science Chapter 5 Covers
5.1 & 5.2 What Are Life Processes? & Nutrition contrasts autotrophic nutrition (photosynthesis: $6\text{CO}_2 + 12\text{H}_2\text{O} \xrightarrow{\text{Chlorophyll, Sunlight}} \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 + 6\text{H}_2\text{O}$, stomatal opening and closing by guard cells) with heterotrophic nutrition (holozoic nutrition in *Amoeba* via pseudopodia, and the human alimentary canal: salivary amylase in the mouth, $\text{HCl}$/pepsin/mucus in the stomach, bile from the liver and pancreatic trypsin/lipase in the small intestine, and absorption by villi).
5.3 Respiration traces the three pathways of glucose breakdown after glycolysis to pyruvate in the cytoplasm: anaerobic fermentation in yeast ($\text{ethanol} + \text{CO}_2 + \text{energy}$), lactic acid formation in muscle cells lacking oxygen (causing cramps), and aerobic breakdown in mitochondria ($\text{CO}_2 + \text{H}_2\text{O} + \text{ATP}$), followed by gas exchange across alveoli in the human lungs.
5.4 & 5.5 Transportation and Excretion covers double circulation through the four-chambered human heart (atria, ventricles, pulmonary vs systemic circulation), arteries, veins, capillaries, platelets and lymph; transport of water and minerals in plants via xylem (root pressure and transpirational pull) and translocation of food via phloem using ATP; and excretion in humans via the kidneys and nephrons (glomerular filtration, selective reabsorption and tubular secretion).
Exercises in Chapter 5
- In-text Questions cover why diffusion is insufficient to meet the oxygen requirements of multicellular organisms, the role of acid in our stomach, why it is necessary to separate oxygenated and deoxygenated blood in mammals and birds, and how water and food are transported in plants.
- Chapter Exercises (13 Questions) compare autotrophic and heterotrophic nutrition, aerobic and anaerobic respiration, alveoli in lungs vs nephrons in kidneys, and explain double circulation.
Read Class 10 Science Chapter 5 Online
More Chapters
- Previous: Chapter 4: Carbon and its Compounds
- Next: Chapter 6: Control and Coordination
- Hindi medium: Class 10 Science Chapter 5 PDF in Hindi (Vigyan)
- All Science chapters and the other Class 10 books: Class 10 NCERT books 2026-27
- All Class 1 to 12 NCERT Textbooks: NCERT Books PDF (Class 1–12)
FAQ
What are the three pathways of glucose breakdown in living organisms?
In the cytoplasm, 6-carbon glucose is broken down into 3-carbon pyruvate. Then: (1) in yeast (absence of $\text{O}_2$), pyruvate turns into ethanol + $\text{CO}_2$; (2) in muscle cells (lack of $\text{O}_2$), into 3-carbon lactic acid; (3) in mitochondria (presence of $\text{O}_2$), into $\text{CO}_2$ + $\text{H}_2\text{O}$ + large energy (ATP).
What is double circulation in humans and why is it necessary?
Blood passes through the human heart twice during each complete cycle through the body (pulmonary circulation to the lungs and systemic circulation to the body). This prevents mixing of oxygenated and deoxygenated blood and ensures a high supply of oxygen needed to maintain constant body temperature.