Bihar Board Class 10 · Science · Matric exam 2027
Chapter 6: Life Processes — notes
The chapter’s 8 parts in the book’s order — the first idea of each and the points Medha Ma’am writes on the board — and the summary at the end. The full lesson and a check question for each part are in the app.
1. What are life processes?
Okay, so — how do you know a sleeping dog is alive?
- • Life processes = processes that together do the maintenance job
- • Needed even when we are asleep
- • Nutrition, respiration, transportation, excretion
- • Multi-cellular: simple diffusion is not enough
2. Autotrophic nutrition: photosynthesis
Okay, so every living thing needs energy and materials, but not everyone gets them the same way.
- • Carbon dioxide + water → carbohydrates
- • Needs sunlight and chlorophyll
- • Extra carbohydrate stored as starch
- • Stomata: tiny pores; guard cells open and close them
- • Variegated leaf + iodine: starch only in green areas
3. Heterotrophic nutrition and digestion in us
Okay, so let's talk about how we get our nutrition.
- • Mouth: salivary amylase: starch → sugar
- • Stomach: hydrochloric acid, pepsin, mucus
- • Small intestine: bile, trypsin, lipase
- • Proteins → amino acids; carbohydrates → glucose
- • Fats → fatty acids + glycerol
- • Villi increase surface area for absorption
4. Respiration: getting energy from glucose
Okay, so — where does your body get energy from?
- • Glucose (6-carbon) → pyruvate (3-carbon), in cytoplasm
- • Yeast, no oxygen: ethanol + carbon dioxide (anaerobic)
- • Mitochondria, oxygen: carbon dioxide + water (aerobic)
- • Muscle, lack of oxygen: lactic acid → cramps
- • ATP = energy currency; 30.5 kJ/mol
5. Breathing and exchange of gases
Okay, so, every aerobic organism needs enough oxygen.
- • Nostrils → throat → lungs → alveoli
- • Alveoli: surface for gas exchange
- • Alveolar surface ≈ 80 m2
- • Haemoglobin (in red blood corpuscles) carries oxygen
- • Carbon dioxide travels mostly dissolved in blood
6. Transportation in human beings
Okay, so — let's talk about blood.
- • Lungs → left atrium → left ventricle → body
- • Body → right atrium → right ventricle → lungs
- • Blood passes the heart twice: double circulation
- • Arteries: away from heart; veins: back to heart, with valves
- • Capillaries: walls one cell thick
- • Normal BP: 120/80 mm of Hg
7. Transportation in plants
Okay, so plants take water and minerals from the soil through their roots.
- • Xylem: water and minerals from soil
- • Phloem: products of photosynthesis
- • Transpiration = loss of water vapour from aerial parts
- • Transpiration pull: main force by day
- • Root pressure: more important at night
- • Translocation in phloem uses ATP
8. Excretion
Okay, so — what happens to the waste your body makes?
- • Excretion = removal of harmful metabolic wastes
- • Kidneys → ureters → urinary bladder → urethra
- • Nephron = filtration unit of kidney
- • Re-absorbed: glucose, amino acids, salts, water
- • Filtrate ≈ 180 L daily; urine 1–2 L
- • Plants: vacuoles, falling leaves, resins, gums, soil
Summary
Okay, so let's quickly go over everything we learnt. Living things keep repairing and maintaining their bodies, remember. And the processes that do this job, we call them life processes. First, nutrition. Autotrophs — like green plants — make carbohydrates from carbon dioxide and water, using sunlight and chlorophyll. Heterotrophs — like you — take in complex food and break it down with enzymes, all along the alimentary canal. Next, respiration. Glucose is broken down to give energy as ATP. This can happen aerobically, in the mitochondria, or anaerobically, as in yeast. In your lungs, gases are exchanged in the alveoli, and haemoglobin carries oxygen. Then, transportation. Your heart, blood and blood vessels carry materials by double circulation. Plants use xylem for water and minerals, and phloem for food. And finally, excretion. The nephrons in your kidneys remove nitrogenous wastes as urine. Plants get rid of their wastes too — through transpiration, vacuoles, falling leaves, resins and gums, and even into the soil. So, tell me — out of all four, which process do you think your body is doing right now, without you even noticing?
AskMedha · Medha Ma’am — Bihar Board Class 10 Science, Chapter 6. Written from the textbook, checked twice.
Questions parents and students ask
- How do I get the "Life Processes" notes as a PDF?
- Press "Save as PDF" — the phone’s print sheet opens; choose "Save as PDF" there. The PDF holds the notes only.
- Where are these notes written from?
- From the chapter’s own textbook text, part by part, in the book’s own terms; a second, independent model then checked every part against the book. The full lesson, a check question for each part and the practice are in the AskMedha app.
The same preparation, with Medha Ma’am — on your phone
Every question of every chapter with its model answer, practice questions in the board’s own shapes, 60 minutes of class a day, written answers marked, a test every Sunday and a WhatsApp report to parents.
Medha Ma’am is an AI teacher, not a live tutor. Every answer is checked twice; a person takes responsibility.