Life Processes: Class 10 short notes
Life Processes is the longest biology chapter in Class 10 and gives the diagrams boards ask most: the digestive system, the heart and the nephron. These notes go through the four processes in order (nutrition, respiration, transport, excretion) with the terms the book uses.
Short notes
- Nutrition is autotrophic (plants make their own food) or heterotrophic (animals and fungi depend on others).
- Photosynthesis: 6CO₂ + 12H₂O → C₆H₁₂O₆ + 6O₂ + 6H₂O, using chlorophyll and sunlight. Three events: light is absorbed by chlorophyll, water splits into hydrogen and oxygen, and CO₂ is reduced to carbohydrate.
- Gases enter and leave leaves through stomata; guard cells open and close them.
- Mouth: salivary amylase breaks starch into sugar. Stomach: HCl makes it acidic, pepsin digests proteins, mucus protects the lining.
- Liver makes bile, which emulsifies fats (breaks them into small droplets). Pancreatic juice has trypsin (proteins) and lipase (fats).
- The small intestine finishes digestion; its finger-like villi increase the surface area for absorption. The large intestine absorbs water.
- Respiration starts in the cytoplasm: glucose breaks into pyruvate. With oxygen, in mitochondria, pyruvate gives CO₂, water and a lot of energy.
- Without oxygen, yeast makes ethanol and CO₂ (fermentation). Our muscles, short of oxygen, make lactic acid, which causes cramps.
- Energy from respiration is stored as ATP, the cell's energy currency.
- In the lungs, air reaches tiny sacs called alveoli, where oxygen enters the blood. Haemoglobin in red blood cells carries oxygen.
- The human heart has four chambers. Blood passes through it twice in one round of the body (double circulation), keeping oxygen-rich and oxygen-poor blood apart.
- Arteries carry blood away from the heart and have thick walls. Veins carry it back and have valves. Capillaries connect them. Platelets help blood clot.
- In plants, xylem carries water and minerals up from the roots; phloem carries food (translocation), using energy from ATP. Transpiration pulls water up.
- Kidneys filter blood; the nephron is their basic unit. Filtration happens in the glomerulus, inside Bowman's capsule. Urine collects in the urinary bladder. Dialysis is an artificial kidney.
At a glance
| Enzyme or juice | Made by | Acts on |
|---|---|---|
| Salivary amylase | Salivary glands | Starch |
| Pepsin | Stomach | Proteins |
| Bile (not an enzyme) | Liver | Emulsifies fats |
| Trypsin | Pancreas | Proteins |
| Lipase | Pancreas | Fats |
Memory tricks
Arteries go Away
Arteries carry blood Away from the heart. Veins visit back.
Xylem for water, phloem for food
"X-ray of water": Xylem carries water; Phloem carries food (P for packed lunch).
Digestion in order: MSSL
Mouth (starch), Stomach (protein), Small intestine (everything finishes), Large intestine (water).
Practice questions
Which part of the nephron filters the blood?
Show answer
Glomerulus. Filtration happens in the glomerulus, a cluster of capillaries inside Bowman's capsule.
Muscle cramps after hard exercise are caused by:
Show answer
Lactic acid. Short of oxygen, muscles break pyruvate into lactic acid.
Bile helps digestion by:
Show answer
Emulsifying fats. Bile breaks fats into small droplets so lipase can act on them.
Food is carried in plants by:
Show answer
Phloem. Phloem moves food from the leaves to other parts (translocation).
Questions
Which diagrams are important in Life Processes?
The human digestive system, the human heart (sectional view), the respiratory system, the nephron, and the open and closed stomata.
Why is double circulation needed?
It keeps oxygen-rich and oxygen-poor blood apart, so the body gets a steady, efficient supply of oxygen, which warm-blooded animals need to keep their body temperature.
Can I turn my own biology notes into short notes and MCQs?
Yes. Add the PDF or photos to TellBrief and choose CBSE once: you get short notes, memory tricks and board-style questions, each linked to its page.