Life Processes - Previous Year Questions Solved Examples (Class 10 Science)
Life processes including nutrition, respiration, and transportation form the core of Class 10 biology. These questions test understanding of how organisms
TL;DR: Life processes including nutrition, respiration, and transportation form the core of Class 10 biology. These questions test understanding of how organ…
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
Life processes including nutrition, respiration, and transportation form the core of Class 10 biology. These questions test understanding of how organisms
Life Processes - Previous Year Questions — Solved Numerical Examples (Step by Step)
Example 1: Distinguish between aerobic and anaerobic respiration. Give one example of each. [3 marks]
Solution: Aerobic respiration occurs in presence of oxygen, produces 38 ATP molecules per glucose, and complete oxidation of glucose occurs with CO2 and H2O as byproducts. Occurs in mitochondria. Example: most animals and plants. Anaerobic respiration occurs without oxygen, produces 2 ATP molecules per glucose, produces lactate in animals or ethanol in plants. Occurs in cytoplasm. Example: muscles during intense exercise (lactate formation) and yeast fermentation (ethanol).
Example 2: Name the blood vessels that carry oxygenated and deoxygenated blood in humans. [2 marks]
Solution: Oxygenated blood is carried by pulmonary veins from lungs to heart and by systemic arteries (aorta) from heart to body. Deoxygenated blood is carried by pulmonary arteries from heart to lungs and by systemic veins (superior and inferior vena cava) from body to heart.
Example 3: What is the role of chlorophyll in photosynthesis? [2 marks]
Solution: Chlorophyll is a green pigment present in chloroplasts. It absorbs light energy from the sun, particularly blue and red wavelengths. This light energy is used to split water molecules and drive the synthesis of ATP and NADPH. These energy carriers are then used to convert CO2 into glucose in the Calvin cycle.
Example 4: How do plants lose water? Explain the significance of this process. [3 marks]
Solution: Plants lose water mainly through transpiration, which is the evaporation of water from leaves through stomata. This process is essential because: (1) It provides the force to pull water up from roots (root pressure alone is insufficient), (2) It helps in cooling the plant by evaporative cooling, (3) It facilitates mineral absorption and transport from soil to all parts, (4) It maintains turgor pressure keeping plants rigid and upright.
Example 5: What is the difference between ingestion and digestion? [2 marks]
Solution: Ingestion is the taking of food into the mouth and initial breakdown by teeth (mechanical digestion). Digestion is the chemical and mechanical breakdown of food into simpler molecules that can be absorbed. Digestion occurs in mouth, stomach, small intestine with help of enzymes and acids.
Example 6: Explain why the small intestine is the main site of absorption of nutrients. [3 marks]
Solution: The small intestine has several structural adaptations for absorption: (1) It has a large surface area due to numerous villi and microvilli, (2) Walls are thin, facilitating diffusion and active transport, (3) Rich blood capillary network absorbs nutrients, (4) Lymph vessels absorb fats, (5) pH is optimal for enzyme activity and nutrient absorption. These features maximize contact between digested food and absorption surface.
Example 7: What would happen to a plant if its stomata were permanently closed? [2 marks]
Solution: If stomata are permanently closed: (1) CO2 cannot enter, photosynthesis would stop, and plant cannot produce food, (2) Water is retained but this causes wilting due to loss of turgor, (3) Gas exchange for respiration cannot occur efficiently, (4) Plant would eventually die due to lack of energy and inability to maintain structure.
Tips
- Always mention the location where processes occur: photosynthesis in chloroplasts, aerobic respiration in mitochondria, digestion in GI tract.
- Use diagrams to show blood flow direction, stomatal structure, and process flow in life processes.
- Connect structure to function: villi in small intestine, large surface area in leaves for gas exchange.
- Remember the equation for photosynthesis and respiration for quick reference.
Frequently Asked Questions
Why is oxygen essential for aerobic respiration?
Oxygen is the final electron acceptor in the electron transport chain. Without it, electrons cannot be transferred, breaking the entire chain and halting ATP production.
How does blood pressure differ between arteries and veins?
Arteries have thick walls and carry blood under high pressure from the heart. Veins have thinner walls and carry blood at low pressure, with valves preventing backflow.
More Science Solved Examples
- Light - Previous Year Questions
- Electricity - Previous Year Questions
- Chemical Reactions and Equations - Previous Year Questions
- Acids Bases and Salts - Previous Year Questions
- Matter in Our Surroundings - Previous Year Questions
- Force and Pressure
🤖 Stuck on any of these? Ask Syllab's free AI Tutor to explain step by step →