MP Board Class 10 Science Chapter 5: Life Processes — Imp…
MP Board Class 10 Science Chapter 5: Life Processes Important Questions — Life Processes is one of the most crucial chapters in the MP Board Class 10 Science syllabus, carrying 8–10 marks in the board exam. This chapter covers nutrition, respiration, transportation, and excretion in living organisms. Mastering these important questions will help you secure top marks in the 2027 MP Board examination.
📑 Table of Contents
- 1. Nutrition: Autotrophic & Heterotrophic
- 2. Respiration: Aerobic & Anaerobic
- 3. Transportation in Humans & Plants
- 4. Excretion in Humans & Plants
- 5. Comparison Tables & Important Diagrams
- 6. Multiple Choice Questions
- 7. Very Short & Short Answer Questions
- 8. Long Answer Questions
- Previous Year Questions
- Frequently Asked Questions
🌱 1. Nutrition: Autotrophic & Heterotrophic
Q1. What is photosynthesis? Write the balanced chemical equation and explain the process.
Answer: Photosynthesis is the process by which green plants synthesize their own food (glucose) using carbon dioxide, water, and sunlight in the presence of chlorophyll.
Chemical equation:
6CO₂ + 6H₂O →(sunlight/chlorophyll)→ C₆H₁₂O₆ + 6O₂
Steps of photosynthesis:
1. Absorption: Chlorophyll absorbs sunlight energy in chloroplasts.
2. Light Reaction (Photolysis): Water splits into hydrogen and oxygen. Oxygen is released as a by-product.
3. Dark Reaction (Calvin Cycle): Hydrogen combines with CO₂ to form glucose.
Key factors affecting photosynthesis: Light intensity, CO₂ concentration, temperature, and water availability.
💡 Exam Tip: Always write the balanced chemical equation of photosynthesis in board exams. Remember — chlorophyll is essential for trapping sunlight, and the oxygen released comes from water (H₂O), not CO₂.
Q2. Differentiate between autotrophic and heterotrophic nutrition with examples.
Answer:
Autotrophic Nutrition: Organisms synthesize their own food from inorganic substances. They use light (photoautotrophs) or chemical energy (chemoautotrophs). Example: Green plants, cyanobacteria, algae.
Heterotrophic Nutrition: Organisms depend on other organisms for food. Types include:
• Holozoic: Ingestion of solid food (humans, amoeba)
• Saprophytic: Feeding on dead/decaying matter (fungi, bacteria)
• Parasitic: Living on/inside a host (tapeworm, cuscuta)
• Symbiotic: Mutual benefit between two organisms (lichens — algae + fungi)
🔑 Key Fact: In amoeba, nutrition occurs through phagocytosis — the cell engulfs food particles by forming pseudopodia, creates a food vacuole, and digests food using enzymes.
Q3. Describe the structure and function of the human digestive system.
Answer: The human digestive system consists of the alimentary canal and associated digestive glands.
Parts and functions:
1. Mouth/Buccal Cavity: Teeth chew food (mechanical digestion), saliva contains amylase that breaks down starch into maltose.
2. Oesophagus: Peristalsis pushes food to stomach.
3. Stomach: Gastric glands secrete HCl (kills bacteria, activates pepsinogen), pepsin (digests proteins), and mucus (protects stomach lining).
4. Small Intestine: Major site of digestion and absorption. Bile (from liver) emulsifies fats, pancreatic juice digests all macromolecules, intestinal villi absorb nutrients.
5. Large Intestine: Absorbs water and minerals, forms faeces.
6. Anus: Expels undigested waste.
🫁 2. Respiration: Aerobic & Anaerobic
Q4. Differentiate between aerobic and anaerobic respiration with chemical equations.
Answer:
Aerobic Respiration: Occurs in the presence of oxygen, producing CO₂, water, and a large amount of energy (38 ATP).
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + 38 ATP (Energy)
Anaerobic Respiration: Occurs in the absence of oxygen, producing lactic acid or ethanol + CO₂, with only 2 ATP.
In muscles: C₆H₁₂O₆ → 2C₃H₆O₃ (Lactic acid) + 2 ATP
In yeast: C₆H₁₂O₆ → 2C₂H₅OH (Ethanol) + 2CO₂ + 2 ATP
Key differences:
Q5. Explain the mechanism of breathing in humans. What is the role of the diaphragm?
Answer: Breathing involves two phases — inhalation and exhalation.
Inhalation (Inspiration): The diaphragm contracts and flattens, and the intercostal muscles pull the rib cage upward and outward. This increases the chest cavity volume, reducing air pressure inside the lungs. Air rushes into the lungs from outside due to the pressure gradient.
Exhalation (Expiration): The diaphragm relaxes and moves upward, intercostal muscles relax, rib cage moves downward, chest volume decreases, air pressure increases, and air is pushed out of the lungs.
Role of diaphragm: The diaphragm is a dome-shaped muscular sheet separating the thoracic cavity from the abdominal cavity. It is the primary muscle of respiration — its contraction and relaxation create the pressure differences necessary for breathing.
🩸 3. Transportation in Humans & Plants
Q6. Describe the structure and function of the human heart. Explain double circulation.
Answer: The human heart is a four-chambered muscular organ (two atria and two ventricles) that pumps blood throughout the body.
Structure:
• Right Atrium: Receives deoxygenated blood from the body via the superior and inferior vena cava.
• Right Ventricle: Pumps deoxygenated blood to the lungs through the pulmonary artery.
• Left Atrium: Receives oxygenated blood from the lungs via the pulmonary vein.
• Left Ventricle: Pumps oxygenated blood to the body through the aorta (thickest wall — needs maximum force).
Double Circulation: Blood passes through the heart twice in one complete cycle:
1. Pulmonary Circulation: Right ventricle → Pulmonary artery → Lungs (gas exchange) → Pulmonary vein → Left atrium.
2. Systemic Circulation: Left ventricle → Aorta → Body organs → Vena cava → Right atrium.
Significance: Double circulation ensures complete separation of oxygenated and deoxygenated blood, allowing efficient oxygen delivery to body tissues — essential for warm-blooded animals.
💡 Exam Tip: In board exams, a labelled diagram of the human heart is frequently asked. Practice drawing: 4 chambers, valves (tricuspid, bicuspid/mitral, semilunar), and major blood vessels (vena cava, pulmonary artery, pulmonary vein, aorta).
Q7. What is the composition and function of blood?
Answer: Blood is a connective tissue that transports nutrients, oxygen, waste products, and hormones throughout the body.
Components of blood:
Q8. How does transportation occur in plants? Explain xylem and phloem.
Answer: Plants have two specialized conducting tissues for transport:
Xylem: Transports water and minerals from roots to leaves (unidirectional, upward).
• Components: Tracheids, vessels, xylem fibres, xylem parenchyma
• Mechanism: Transpiration pull — water evaporates from leaf stomata, creating negative pressure that pulls water upward through xylem vessels
Phloem: Transports food (sucrose, amino acids) from leaves to other parts (bidirectional).
• Components: Sieve tubes, companion cells, phloem fibres, phloem parenchyma
• Mechanism: Translocation — uses ATP energy to load/unload sucrose at source (leaves) and sink (roots, fruits, growing tissues)
🧪 4. Excretion in Humans & Plants
Q9. Explain the structure and function of the human excretory system. Describe the process of urine formation.
Answer: The human excretory system removes nitrogenous waste (urea) from the body.
Organs: A pair of kidneys, ureters, urinary bladder, and urethra.
Structure of Nephron (functional unit of kidney):
1. Bowman’s Capsule: Cup-shaped structure containing a tuft of capillaries called the glomerulus.
2. Proximal Convoluted Tubule (PCT): Reabsorption of glucose, amino acids, and ions.
3. Loop of Henle: Maintains concentration gradient; reabsorbs water and salts.
4. Distal Convoluted Tubule (DCT): Selective reabsorption and secretion.
5. Collecting Duct: Final concentration of urine; drains into ureter.
Urine Formation (3 steps):
1. Glomerular Filtration: Blood pressure forces water, glucose, urea, and salts from glomerulus into Bowman’s capsule (filtrate ~180 L/day).
2. Reabsorption: Useful substances (glucose, amino acids, 99% water) are reabsorbed into blood.
3. Secretion: Additional waste (H⁺, K⁺, drugs) is secreted into the tubule.
Final urine: ~1.5 L/day, containing urea, uric acid, creatinine, excess salts, and water.
Q10. How do plants excrete waste products?
Answer: Plants do not have specialized excretory organs. They use various methods to remove waste:
1. Gaseous waste (O₂, CO₂): Released through stomata during photosynthesis and respiration.
2. Solid waste: Stored in vacuoles, old leaves, bark, and heartwood that are shed periodically.
3. Latex and resins: Stored in specialized ducts (rubber, gum, resins).
4. Transpiration: Excess water is removed through stomata as water vapour.
5. Alkaloids and tannins: Stored in leaves and bark (e.g., caffeine, nicotine) — these also protect plants from herbivores.
📊 5. Comparison Tables & Important Diagrams
Comparison: Arteries vs Veins
Important Diagrams to Practice
Diagrams frequently asked in MP Board exams:
1. Human Digestive System — Alimentary canal with all glands
2. Human Respiratory System — Nasal cavity to alveoli
3. Human Heart — 4 chambers with valves and blood vessels
4. Nephron — Structure with Bowman’s capsule, tubules, collecting duct
5. Stomata — Guard cells, chloroplast, and pore
6. Cross-section of Leaf — Showing mesophyll, vascular bundle, stomata
7. Open and Closed Stomatal Pore — Turgid vs flaccid guard cells
📝 6. Multiple Choice Questions (1 Mark Each)
MCQs are frequently asked in the MP Board Class 10 Science exam. Here are 10 important MCQs from Chapter 5: Life Processes.
- The green pigment present in leaves that traps sunlight is:
(a) Haemoglobin ✓ (b) Chlorophyll (c) Carotene (d) Xanthophyll - The process by which amoeba ingests food is called:
(a) Pinocytosis (b) Phagocytosis ✓ (c) Exocytosis (d) Diffusion - The enzyme in human saliva that breaks down starch is:
(a) Pepsin (b) Trypsin (c) Amylase ✓ (d) Lipase - The site of aerobic respiration in a cell is:
(a) Nucleus (b) Ribosome (c) Mitochondria ✓ (d) Golgi apparatus - Which of the following blood vessels carries deoxygenated blood from the heart to the lungs?
(a) Aorta (b) Pulmonary artery ✓ (c) Pulmonary vein (d) Vena cava - The functional unit of the human kidney is:
(a) Neuron (b) Nephron ✓ (c) Alveolus (d) Villus - Which vitamin is produced in human skin in the presence of sunlight?
(a) Vitamin A (b) Vitamin B (c) Vitamin C (d) Vitamin D ✓ - The muscular structure that separates the thoracic cavity from the abdominal cavity is called:
(a) Pleura (b) Diaphragm ✓ (c) Pericardium (d) Mesentery - In plants, food is transported through:
(a) Xylem (b) Phloem ✓ (c) Cambium (d) Epidermis - Which of the following is an anaerobic organism?
(a) Human (b) Earthworm (c) Yeast ✓ (d) Mango tree
✏️ 7. Very Short & Short Answer Questions (2–4 Marks)
- What is the role of hydrochloric acid in the stomach?
HCl kills harmful bacteria in food, creates an acidic medium (pH ~2) required for pepsin to digest proteins, and prevents food spoilage in the stomach. (2 marks) - Why does the small intestine have villi? What is their function?
The inner lining of the small intestine has finger-like projections called villi that increase the surface area for absorption of digested food. Each villus has a network of blood capillaries and a lacteal to absorb nutrients into the bloodstream. (2 marks) - What is the role of platelets in blood clotting?
Platelets (thrombocytes) release thromboplastin at the site of injury. Thromboplastin converts prothrombin (inactive) into thrombin (active) in the presence of calcium ions. Thrombin then converts soluble fibrinogen into insoluble fibrin threads, forming a mesh that traps blood cells and forms a clot. (3 marks) - Write the difference between transpiration and translocation in plants.
Transpiration is the loss of water vapour through stomata, driven by sunlight; it creates a pull that moves water upward in xylem. Translocation is the active transport of food (sucrose) through phloem, using ATP energy, and can move in both directions (source to sink). (3 marks) - What is the importance of the closing and opening of stomata?
Guard cells regulate stomatal opening. When turgid, stomata open for gas exchange (CO₂ intake for photosynthesis, O₂ release). When flaccid (during water scarcity or hot afternoons), stomata close to reduce water loss through transpiration. This balance is critical for plant survival. (3 marks) - Explain the mechanism of breathing in human beings in two steps.
Inhalation: Diaphragm contracts and flattens, rib cage moves upward and outward — chest cavity volume increases, air pressure decreases — air rushes in. Exhalation: Diaphragm relaxes and moves upward, rib cage moves down — chest volume decreases, air pressure increases — air is pushed out. (3 marks) - Define excretion. Name the excretory organs in humans and the main excretory waste.
Excretion is the biological process of removing metabolic waste products from the body. In humans, the excretory organs are: kidneys (remove urea and excess water as urine), skin (removes sweat containing salts and urea), lungs (remove CO₂), and liver (converts ammonia to urea). The main nitrogenous waste is urea. (3 marks) - Why is diffusion insufficient to meet the oxygen requirements of large multicellular organisms?
In large multicellular organisms, the surface area-to-volume ratio is very small. Diffusion is a slow process that can only move substances over short distances (a few millimetres). Specialized transport systems (circulatory and respiratory systems) are needed to quickly carry oxygen to all body cells and remove waste. (4 marks)
📝 8. Long Answer Questions (5–6 Marks)
Q1. With the help of a labelled diagram, explain the process of nutrition in amoeba.
Answer: Amoeba exhibits holozoic nutrition through phagocytosis. The process involves five steps:
1. Ingestion: Amoeba extends pseudopodia (false feet) around food particles. The cell membrane engulfs the food, forming a food vacuole inside the cytoplasm.
2. Digestion: Lysosomes fuse with the food vacuole and release digestive enzymes. Proteins are broken into amino acids, carbohydrates into glucose, and fats into fatty acids.
3. Absorption: Digested nutrients diffuse from the food vacuole into the surrounding cytoplasm for energy and growth.
4. Assimilation: Absorbed nutrients are used for cellular metabolism, growth, and reproduction.
5. Egestion: Undigested waste is carried to the cell surface. The food vacuole fuses with the cell membrane, and waste is expelled outside (exocytosis).
Key point: Unlike humans who have a separate mouth and anus, amoeba performs both ingestion and egestion through the same cell surface.
Q2. Describe the process of digestion of food in the human alimentary canal. Add a note on the role of various digestive glands.
Answer: Digestion is the breakdown of complex food into simple, absorbable forms. It occurs in the alimentary canal with help from digestive glands.
Step-by-step digestion:
1. Mouth: Teeth grind food into smaller pieces (mechanical digestion). Salivary amylase breaks starch into maltose (chemical digestion). Food is formed into a bolus.
2. Oesophagus: Peristaltic contractions push the bolus to the stomach. No digestion occurs here.
3. Stomach: Gastric glands secrete:
• HCl: Creates acidic medium (pH 2), kills germs, activates pepsinogen
• Pepsin: Digests proteins into peptides
• Mucus: Protects stomach lining from acid
Food becomes semi-fluid chyme after 3-4 hours.
4. Small Intestine (duodenum): Three digestive juices act here:
• Bile (from liver): Emulsifies fats into tiny droplets (no enzymatic digestion; physical breakdown)
• Pancreatic juice (from pancreas): Contains trypsin (digests proteins), lipase (digests fats into fatty acids + glycerol), and amylase (digests remaining starch)
• Intestinal juice (sucus entericus): Contains maltase (maltose → glucose), sucrase (sucrose → glucose + fructose), lactase (lactose → glucose + galactose), and peptidases (peptides → amino acids)
5. Absorption in Ileum: Villi and microvilli increase surface area. Glucose, amino acids, vitamins, minerals enter blood capillaries; fatty acids and glycerol enter lacteals (lymphatic system).
6. Large Intestine: Absorbs water and minerals; houses gut bacteria that produce vitamin K and B vitamins. Faeces are formed and stored temporarily.
7. Anus: Expels undigested waste (defecation).
Digestive glands summary: Salivary glands (mouth), Gastric glands (stomach), Liver (largest gland, produces bile), Pancreas (dual role — endocrine + exocrine), Intestinal glands (small intestine).
Q3. Explain double circulation in human beings. Why is it necessary for warm-blooded animals?
Answer: Double circulation means blood passes through the heart twice during one complete cycle — once as deoxygenated blood (to lungs) and once as oxygenated blood (to the body).
Pathway of blood through the heart:
Step 1 — Deoxygenated blood enters: Deoxygenated blood from all body parts collects in the right atrium via the superior vena cava (from upper body) and the inferior vena cava (from lower body).
Step 2 — Right side pumping: The right atrium contracts, pushing blood through the tricuspid valve into the right ventricle. The right ventricle contracts, pumping blood through the pulmonary semilunar valve into the pulmonary artery, which carries it to the lungs.
Step 3 — Oxygenation in lungs: In the pulmonary capillaries surrounding the alveoli, CO₂ is released and O₂ is absorbed. Oxygenated blood returns through the pulmonary veins to the left atrium.
Step 4 — Left side pumping: The left atrium contracts, pushing blood through the bicuspid (mitral) valve into the left ventricle. The left ventricle (thickest chamber) contracts powerfully, sending oxygenated blood through the aortic semilunar valve into the aorta.
Step 5 — Systemic circulation: The aorta branches into arteries → arterioles → capillaries throughout the body, delivering oxygen and nutrients. Deoxygenated blood returns through venules → veins → vena cavae back to the right atrium.
Why necessary for warm-blooded animals?
Warm-blooded (endothermic) animals — humans, birds, mammals — maintain a constant body temperature regardless of the environment. This requires a high metabolic rate, which in turn demands:
1. Efficient O₂ delivery: Double circulation ensures oxygenated and deoxygenated blood never mix, maximizing O₂ supply to tissues.
2. High blood pressure: The left ventricle pumps blood at high pressure to reach all body parts quickly.
3. Rapid waste removal: Faster circulation means faster removal of CO₂ and metabolic waste.
4. Thermoregulation: Blood redistributes heat throughout the body to maintain constant temperature.
📋 Previous Year Questions (2017–2026)
❓ Frequently Asked Questions
Q1. What are life processes? Name them.
Life processes are the basic functions performed by living organisms to maintain life. They include: nutrition, respiration, transportation, excretion, growth, reproduction, and response to stimuli.
Q2. What is the difference between autotrophic and heterotrophic nutrition?
Autotrophic organisms (green plants) produce their own food using sunlight and CO₂. Heterotrophic organisms (animals, fungi) depend on other organisms for food because they cannot synthesize their own food.
Q3. Why is the small intestine the longest part of the alimentary canal?
The small intestine is about 6-7 meters long to provide a large surface area for complete digestion and maximum absorption of nutrients through its villi and microvilli.
Q4. What is the role of hydrochloric acid in the stomach?
HCl creates an acidic medium (pH ~2) that activates pepsinogen into pepsin, kills bacteria entering with food, and prevents food decay in the stomach.
Q5. Where does aerobic respiration occur in cells?
Aerobic respiration occurs in the mitochondria (the powerhouse of the cell). The Krebs cycle occurs in the mitochondrial matrix, and the electron transport chain occurs on the inner mitochondrial membrane.
Q6. What causes muscle cramps after heavy exercise?
During strenuous exercise, oxygen supply is insufficient for aerobic respiration. Muscles switch to anaerobic respiration, producing lactic acid. Accumulation of lactic acid causes muscle cramps and fatigue.
Q7. What is the function of the pulmonary vein?
The pulmonary vein carries oxygenated blood from the lungs to the left atrium of the heart. It is the only vein in the body that carries oxygenated blood.
Q8. Why does the left ventricle have a thicker wall than the right ventricle?
The left ventricle pumps oxygenated blood to the entire body, requiring higher pressure. The right ventricle only pumps blood to the nearby lungs, needing less force.
Q9. What is the excretory unit of the kidney?
The nephron is the structural and functional unit of the kidney. Each kidney has about 1 million nephrons that filter blood and produce urine.
Q10. How do plants excrete excess water?
Plants excrete excess water through transpiration — water vapour is released through stomata. In some plants, guttation (water droplets) occurs through hydathodes at leaf tips.
Q11. What is the role of bile in digestion?
Bile, produced by the liver and stored in the gallbladder, emulsifies fats into tiny droplets. This increases the surface area for lipase enzyme to act, making fat digestion more efficient.
Q12. What is the difference between holozoic and saprophytic nutrition?
Holozoic nutrition involves ingesting solid food and digesting it internally (humans, animals). Saprophytic nutrition involves absorbing nutrients from dead/decaying organic matter externally (fungi, bacteria).