Practice Questions for Science Class 10th "Life Processes"

Multiple Choice Questions (MCQs):

1. C) Combustion - Combustion is not a life process; it's a chemical process where substances react with oxygen to release energy.
2. B) Photosynthesis - Plants synthesize their food through this process, converting light energy into chemical energy.
3. B) Amylase - Salivary amylase begins the digestion of starch into sugars in the mouth.
4. B) Small intestine - The majority of nutrient absorption occurs here due to the presence of villi.
5. A) Haemoglobin - This protein in red blood cells binds with oxygen for transport.
6. B) Mitochondria - Known as the powerhouse for producing ATP through cellular respiration.
7. C) Excretion - This is the process of removing metabolic waste from the body.
8. D) All of the above - Transpiration aids in water absorption, cooling, and mineral transport.
9. B) Xylem - Xylem tissue transports water and minerals from roots to other parts of the plant.
10. B) Arteries - Arteries carry oxygenated blood away from the heart to the body's tissues.
11. B) Lactic acid - Anaerobic respiration in muscles leads to lactic acid accumulation.
12. C) To emulsify fats - Bile from the liver helps in breaking down large fat globules into smaller ones for digestion.
13. A) To filter blood - Kidneys filter blood to remove waste products, excess water, and salts.
14. C) Pancreas - The pancreas is part of the digestive system, not the respiratory system.
15. C) Digestion - Digestion breaks down complex food molecules into simpler ones.
16. B) Chlorophyll - Chlorophyll captures light energy for photosynthesis.
17. C) 4 - The human heart has two atria and two ventricles.
18. D) All of these - All plant parts respire, though leaves are primary due to high metabolic activity.
19. C) Kidneys - Urea, a waste product of protein metabolism, is excreted mainly by kidneys.
20. B) Alveoli - Gas exchange occurs in the alveoli where oxygen enters and carbon dioxide exits the blood.

Short Answer Questions:

21. Autotrophic Nutrition: The process by which organisms produce their own food from inorganic substances using light (photosynthesis) or chemical energy.
22. Role of Hydrochloric Acid: It kills bacteria, activates pepsinogen to pepsin for protein digestion, and provides an acidic environment for enzyme activity in the stomach.
23. Aerobic vs. Anaerobic Respiration:

• Aerobic: Uses oxygen, produces more energy, end products are CO₂ and H₂O.
• Anaerobic: No oxygen, less energy produced, end products can be lactic acid in animals or ethanol in yeast.

24. Benefits of Transpiration:

• Cools the plant, helps in water and mineral transport, and maintains turgidity for plant support.

25. Functions of Circulatory System: Transports oxygen, nutrients, hormones, removes waste, regulates body temperature, and aids in immunity.
26. Structure of a Nephron:

• Consists of glomerulus (for filtration), Bowman's capsule, proximal convoluted tubule, loop of Henle, distal convoluted tubule, and collecting duct (for reabsorption and secretion).

27. Significance of Villi: Increase surface area for absorption, allowing nutrients to pass into the bloodstream efficiently.
28. Oxygenation of Blood: Blood gets oxygenated in the lungs at the alveoli, where oxygen diffuses into the blood and CO₂ diffuses out.
29. Liver's Role in Digestion: Produces bile, detoxifies blood, stores glycogen, and processes nutrients.
30. Regulation of Blood Glucose: Pancreas secretes insulin to lower blood sugar when high and glucagon to raise it when low.
31. Respiratory System as an Upside-Down Tree: The trachea branches into bronchi, which further divide into bronchioles, ending in alveoli, resembling an inverted tree.
32. Importance of Large Intestine: Absorbs water and electrolytes, forms and stores feces until egestion.
33. Food Transport in Plants: Phloem transports sugars from leaves (source) to other parts (sinks) through a process called translocation.
34. Homeostasis: The body's ability to maintain a stable internal environment despite external changes, e.g., regulating temperature, pH, and glucose levels.
35. Role of Diaphragm: Contracts and flattens to increase thoracic volume, causing inhalation, and relaxes for exhalation.
36. Photolysis in Photosynthesis: Light energy splits water molecules into oxygen, protons, and electrons in the light-dependent reactions.
37. Temperature Regulation: Through mechanisms like sweating, vasodilation/vasoconstriction, shivering, and behavioral adaptations.
38. Significance of Root Hair: Increases surface area for water and nutrient absorption from the soil.
39. Double Circulation: Blood passes through the heart twice for each complete circuit of the body, once for pulmonary circulation (to lungs) and once for systemic circulation (to body).
40. Stomata and Water Loss: Stomata open to allow gas exchange, potentially leading to water loss. They close to conserve water, regulated by guard cells.

Long Answer Questions:

41. Digestion Process:

• Ingestion: Food enters the mouth.
• Digestion: Mechanical (chewing) and chemical (enzymes) in mouth, stomach, and small intestine.
• Absorption: Nutrients absorbed in the small intestine.
• Assimilation: Nutrients used by cells.
• Egestion: Undigested material leaves as feces.

42. Mechanism of Photosynthesis:

• Light-dependent: Occurs in thylakoids, light energy converts to ATP and NADPH, oxygen released.
• Light-independent (Calvin Cycle): In stroma, CO₂ is fixed into carbohydrates using ATP and NADPH.

43. Human Respiratory System:

• Air enters through nose/mouth to pharynx, larynx, trachea, bronchi, bronchioles, to alveoli where gas exchange happens. Oxygen diffuses into blood, CO₂ out.

44. Role of Circulatory System:

• Transports gases, nutrients, hormones, waste, maintains pH and temperature, and supports immune response through blood flow.

45. Excretion in Humans:

• Kidneys filter blood, reabsorb needed substances, and excrete waste (urea, uric acid) as urine, which goes through ureters to bladder for storage and expulsion.

46. Transport Systems Comparison:

• Plants: Xylem (water) and phloem (nutrients). Passive (transpiration pull) and active (translocation).
• Animals: Blood vessels (arteries, veins, capillaries), heart pumps blood, circulatory system is closed.

47. Interlinking Life Processes in Plants:

• Photosynthesis provides energy, respiration uses this energy, transpiration aids in water and nutrient movement, all supporting growth, repair, and reproduction.

48. Waste Management in Humans:

• Kidneys: Excrete urea, manage water and salt balance.
• Lungs: Remove CO₂.
• Skin: Sweats out salts, urea.
• Liver: Detoxifies blood, excretes bile.

49. Water Pathway in Plants:

• From soil, through root hairs, into root xylem, up through the stem xylem to leaves via transpiration pull.

50. pH Regulation:

• Kidneys adjust bicarbonate and hydrogen ions, lungs control CO₂ levels which affects blood pH, buffers in blood maintain pH stability.

51. Enzymes in Biological Processes:

• Digestion: Amylase, pepsin, lipase catalyze food breakdown.
• Metabolism: Enzymes like ATP synthase in energy production.

52. Adaptation to High Altitudes:

• Increased red blood cell production, enhanced lung capacity, and physiological adjustments for better oxygen use.

53. Lock and Key Model:

• Enzymes have specific shapes that only match certain substrates, like a key fits a lock, for catalysis.

54. Physiological Responses to Exercise:

• Increased heart rate, breathing rate, blood flow to muscles, energy production shifts to anaerobic if oxygen supply lags.

55. Plant Responses to Environment:

• Tropisms (like phototropism), stomatal opening/closing, seasonal changes in growth patterns, and dormancy.

56. Preventing Dehydration:

• Thirst mechanism, ADH secretion to increase water reabsorption, reducing sweat production, and behavioral changes.

57. Nervous System in Life Processes:

• Coordinates responses like heart rate, digestion, hormone release, and sensory responses via nerve signals.

58. Lifestyle Impact on Life Processes:

• Diet affects digestion, circulation, and respiratory health; exercise impacts cardiovascular fitness, smoking harms lungs and circulation.

59. Vascular System in Plants:

• Provides support (xylem for rigidity), transports water (xylem), and nutrients (phloem), crucial for growth and survival.

60. Osmosis:

• Water movement across a semi-permeable membrane from higher to lower concentration. In plants, it maintains cell turgor; in animals, manages water balance in cells.

Application-Based Questions:

61. Experiment for Light Necessity in Photosynthesis:

• Use a plant with variegated leaves, destarch it, cover part of a leaf with black paper, expose to light, then test for starch with iodine (starch in light-exposed areas).

62. Proving CO₂ Necessity:

• Place a plant in a bell jar with KOH (absorbs CO₂), another without. Test for starch; only the plant with CO

63. Action of Saliva on Starch:

• Mix saliva with starch solution, split into two parts. One part remains at room temperature; the other is heated to denature the enzyme. Use iodine to test for starch; the unheated part should show less color change, indicating starch digestion.

64. Presence of Urea in Urine:

• Use urease enzyme, which converts urea to ammonia. Add urease to a urine sample, then test with litmus paper; if it turns blue, ammonia is present, indicating urea.

65. Oxygen Production in Photosynthesis:

• Submerge a water plant (like Elodea) in water under light. Bubbles of oxygen will be seen escaping from the plant, which can be collected and tested with a glowing splint (relights in oxygen).

66. Measuring Transpiration Rate:

• Use a potometer to measure water uptake by a plant, which correlates with transpiration. Adjust environmental conditions like humidity or light to observe changes in rate.

67. pH Effect on Enzyme Activity:

• Prepare several test tubes with the enzyme at different pH levels, add substrate, and measure the reaction rate (e.g., color change or product formation). Plot results to show optimal pH.

68. Anaerobic Respiration in Yeast:

• Mix yeast with glucose solution in a sealed container with a balloon on top. The balloon inflates due to CO₂ from fermentation, demonstrating anaerobic respiration.

69. Testing Glucose in Blood:

• Use a glucose meter or test strips that change color based on glucose concentration. Blood is applied to the strip, and the meter reads the glucose level.

70. Demonstrating Gas Exchange in Lungs:

• Construct a model with balloons inside a bottle (lungs), with one balloon representing the diaphragm. Pulling the diaphragm down simulates inhalation, showing how the "lungs" expand and contract.

Critical Thinking Questions:

71. Environmental Conditions and Life Processes:

• Plants: Temperature, light, water availability can affect photosynthesis, growth, and reproduction.
• Animals: Climate changes can influence metabolic rates, hibernation, migration, and survival strategies.

72. Poor Kidney Function Implications:

• Leads to waste accumulation, electrolyte imbalance, affects blood pressure, and can strain other organs like the heart. It impacts water balance, pH regulation, and erythropoiesis.

73. Efficiency of Human Digestive System:

• Long small intestine with villi for absorption, specialized organs like liver and pancreas for enzyme secretion, and efficient breakdown of a wide range of nutrients.

74. Life Processes in Disease Management:

• Understanding metabolism for diabetes management, respiratory processes for lung diseases, circulatory for cardiovascular issues, enabling targeted treatments like enzyme replacement or dialysis.

75. Closed vs. Open Circulatory Systems:

• Closed systems allow for precise control of blood flow, efficient delivery of oxygen and nutrients, and better regulation of blood pressure, advantageous for complex organisms.

76. Lung Structure for Gas Exchange:

• Large surface area due to numerous alveoli, thin walls for diffusion, rich blood supply, and moist surfaces for gas exchange efficiency.

77. Ethical Considerations in Animal Testing:

• Concerns include animal welfare, pain, consent (though not applicable to animals), alternatives like cell cultures or computer simulations, and the relevance of animal models to human biology.

78. Global Warming and Photosynthesis:

• Higher CO₂ might initially boost photosynthesis, but increased temperatures, altered precipitation patterns, and extreme weather can stress plants, reducing efficiency or causing habitat loss.

79. Life Processes and Dietary Recommendations:

• Understanding metabolism and nutrient absorption influences recommendations on macro and micronutrients, fiber for gut health, and hydration for kidney function.

80. Feedback Mechanisms for Stability:

• Negative feedback loops like insulin-glucose regulation maintain homeostasis. Positive feedback can amplify responses in childbirth or blood clotting, ensuring quick, effective responses when needed.