Subject: Science (Biology) - World of Living
Target Syllabus: Life Processes, Control and Co-ordination, Reproduction, Heredity and Evolution.
This article contains 100 Important VSAQ (Very Short Answer Questions) and SAQ (Short Answer Questions) to help you prepare for your exams.
PART 1: LIFE PROCESSES
Q1. What are Life Processes?
Ans: The basic essential activities performed by an organism to maintain its life, such as nutrition, respiration, transportation, and excretion, are called life processes.
Q2. What is the basic difference between autotrophic and heterotrophic nutrition?
Ans: In autotrophic nutrition, organisms (like green plants) synthesize their own food using inorganic substances (CO2 and water). In heterotrophic nutrition, organisms (like animals) depend on other organisms for food.
Q3. Write the balanced chemical equation for photosynthesis.
Ans: 6CO2 + 12H2O → (in presence of sunlight and chlorophyll) → C6H12O6 + 6O2 + 6H2O.
Q4. What is the role of stomata in plants?
Ans: Stomata allow the exchange of gases (oxygen and carbon dioxide) and help in transpiration (loss of excess water).
Q5. Name the energy currency of the cell.
Ans: ATP (Adenosine Triphosphate).
Q6. What is the function of bile juice?
Ans: Bile juice, secreted by the liver, emulsifies fats (breaks down large fat globules into smaller ones) and makes the food medium alkaline for pancreatic enzymes to act.
Q7. What is peristalsis?
Ans: The rhythmic contraction and relaxation of the muscles of the alimentary canal to push food forward is called peristalsis.
Q8. Differentiate between aerobic and anaerobic respiration.
Ans: Aerobic respiration takes place in the presence of oxygen and produces more energy. Anaerobic respiration takes place in the absence of oxygen and produces less energy.
Q9. What causes cramps in muscles during sudden physical activity?
Ans: The accumulation of lactic acid due to the anaerobic breakdown of glucose causes muscle cramps.
Q10. What is the function of villi in the small intestine?
Ans: Villi increase the surface area for the absorption of digested food into the blood.
Q11. Name the respiratory pigment in human beings. Where is it found?
Ans: Haemoglobin. It is found in the Red Blood Cells (RBCs).
Q12. What is double circulation?
Ans: In humans, blood passes through the heart twice in one complete cycle of the body (Systemic and Pulmonary circulation). This is called double circulation.
Q13. What is the function of Xylem?
Ans: Xylem transports water and minerals from roots to the other parts of the plant.
Q14. What is the function of Phloem?
Ans: Phloem transports food (products of photosynthesis) from leaves to other parts of the plant. This process is called translocation.
Q15. Why is the left ventricle wall thicker than the right ventricle?
Ans: The left ventricle has to pump blood to all parts of the body under high pressure, whereas the right ventricle only pumps blood to the lungs.
Q16. What is the structural and functional unit of the kidney?
Ans: Nephron.
Q17. Define Excretion.
Ans: The biological process of removing harmful nitrogenous metabolic wastes from the body is called excretion.
Q18. What is the role of platelets in blood?
Ans: Platelets help in the clotting of blood at the site of injury to prevent excessive bleeding.
Q19. Name the enzyme present in saliva and state its function.
Ans: Salivary amylase. It breaks down starch into sugar (maltose).
Q20. How do plants excrete waste products?
Ans: Plants excrete oxygen through stomata, store wastes in vacuoles, shed old leaves, or release gums and resins.
Q21. What is the function of the epiglottis?
Ans: It prevents the entry of food into the windpipe (trachea) during swallowing.
Q22. What is lymph?
Ans: Lymph is a clear fluid similar to plasma but containing less protein. It carries digested and absorbed fat from the intestine and drains excess fluid from extracellular space back into the blood.
Q23. Why is transpiration important for plants?
Ans: It creates a suction pull which helps in the absorption and upward movement of water and minerals. It also helps in temperature regulation.
Q24. What is the site of complete digestion in humans?
Ans: Small Intestine.
Q25. Why do fishes breathe faster than terrestrial animals?
Ans: Because the amount of dissolved oxygen in water is much lower than the amount of oxygen in the air.
Q26. What is the role of HCl in the stomach?
Ans: It kills bacteria entering with food and creates an acidic medium for the enzyme Pepsin to act.
Q27. Name the three parts of the small intestine.
Ans: Duodenum, Jejunum, and Ileum.
Q28. What is dialysis?
Ans: Dialysis is the procedure used to clean the blood of a person by separating the waste products (urea) using an artificial kidney when both kidneys fail.
Q29. What is the glottis?
Ans: The slit-like opening of the trachea (windpipe).
Q30. What is residual volume in lungs?
Ans: The volume of air that remains in the lungs even after maximum forceful expiration to prevent lung collapse.
PART 2: CONTROL AND CO-ORDINATION
Q31. What is the structural and functional unit of the nervous system?
Ans: Neuron (Nerve cell).
Q32. What is a Synapse?
Ans: The microscopic gap between two neurons where the electrical impulse is converted into a chemical signal to pass to the next neuron.
Q33. Name the plant hormone responsible for growth (cell elongation).
Ans: Auxin.
Q34. Which plant hormone inhibits growth and causes wilting of leaves?
Ans: Abscisic Acid.
Q35. Define Phototropism.
Ans: The movement of a plant part in response to light. (e.g., shoot bends towards light).
Q36. What is Geotropism?
Ans: The directional movement of plant parts in response to gravity. Roots show positive geotropism.
Q37. Which part of the brain controls posture and balance?
Ans: Cerebellum.
Q38. What is a Reflex Action?
Ans: It is a sudden, involuntary, and automatic response to a stimulus (e.g., withdrawing hand from a hot object).
Q39. What is a Reflex Arc?
Ans: The pathway taken by nerve impulses in a reflex action (Receptor → Sensory Neuron → Spinal Cord → Motor Neuron → Effector).
Q40. Which hormone controls blood sugar levels?
Ans: Insulin, secreted by the Pancreas.
Q41. Name the master gland of the body.
Ans: Pituitary Gland.
Q42. What is the function of the Thyroid gland?
Ans: It secretes Thyroxine, which regulates carbohydrate, protein, and fat metabolism in the body for balanced growth.
Q43. Why is iodized salt recommended?
Ans: Iodine is essential for the synthesis of Thyroxine. Its deficiency causes Goitre (swollen neck).
Q44. What is the function of Cytokinins?
Ans: They promote cell division and are present in greater concentration in fruits and seeds.
Q45. Which hormone helps in facing emergency situations (Flight or Fight)?
Ans: Adrenaline (secreted by Adrenal glands).
Q46. Differentiate between voluntary and involuntary actions.
Ans: Voluntary actions are controlled by our will (e.g., walking), controlled by the Cerebrum. Involuntary actions occur without our will (e.g., heartbeat), controlled by the Medulla and mid-brain.
Q47. What is the role of the Skull and Vertebral column?
Ans: The skull protects the Brain, and the Vertebral column protects the Spinal Cord.
Q48. How do climbing plants tendrils act?
Ans: Tendrils differ in their growth due to Thigmotropism (response to touch). The part touching the support grows slower than the part away, causing it to curl around the support.
Q49. What is Chemotropism? Give an example.
Ans: Movement of plant parts in response to chemicals. Example: Growth of pollen tube towards the ovule.
Q50. Which part of the brain is responsible for thinking and memory?
Ans: Cerebrum (Forebrain).
Q51. What is the function of Gustatory receptors and Olfactory receptors?
Ans: Gustatory receptors detect taste; Olfactory receptors detect smell.
Q52. How does the nervous tissue cause muscle movement?
Ans: Nerve impulses trigger the release of special proteins in muscle cells, changing their shape and arrangement, causing contraction.
Q53. What is Hydrotropism?
Ans: The movement of plant parts (roots) towards water.
Q54. Which hormone is responsible for the development of male secondary sexual characters?
Ans: Testosterone.
Q55. Which hormone is responsible for the development of female secondary sexual characters?
Ans: Estrogen.
PART 3: REPRODUCTION
Q56. What is the importance of DNA copying in reproduction?
Ans: It ensures that the offspring receive similar body designs and characteristics from the parent, maintaining the species' consistency.
Q57. Name the method of asexual reproduction in Amoeba.
Ans: Binary Fission.
Q58. What is Regeneration? Give an example.
Ans: The ability of an organism to give rise to a new organism from its body parts. Example: Planaria, Hydra.
Q59. What is Vegetative Propagation?
Ans: A method of asexual reproduction where new plants are produced from roots, stems, or leaves (e.g., Potato eyes, Bryophyllum leaves).
Q60. Differentiate between self-pollination and cross-pollination.
Ans: Self-pollination is the transfer of pollen within the same flower. Cross-pollination is the transfer of pollen from one flower to another of a different plant of the same species.
Q61. What happens after fertilization in a flower?
Ans: The zygote divides to form an embryo, the ovule develops into a seed, and the ovary ripens into a fruit.
Q62. Where does fertilization take place in humans?
Ans: Fallopian Tube (Oviduct).
Q63. What is the Placenta? State its function.
Ans: It is a disc-shaped tissue connecting the embryo to the mother’s uterine wall. It provides nutrition and oxygen to the embryo and removes waste products.
Q64. Why are testes located outside the abdominal cavity in the scrotum?
Ans: Sperm formation requires a temperature 2-3°C lower than the normal body temperature.
Q65. What is Puberty?
Ans: The age at which reproductive organs become functional and sex hormones are produced, leading to sexual maturity.
Q66. Name two Sexually Transmitted Diseases (STDs) caused by bacteria.
Ans: Syphilis and Gonorrhoea.
Q67. Name two STDs caused by viruses.
Ans: Warts and HIV-AIDS.
Q68. What does HIV stand for?
Ans: Human Immunodeficiency Virus.
Q69. List some methods of contraception (Family Planning).
Ans: Mechanical barriers (Condoms), Chemical methods (Oral pills), IUCD (Copper-T), and Surgical methods (Vasectomy/Tubectomy).
Q70. What is Menstruation?
Ans: If the egg is not fertilized, the lining of the uterus breaks down and comes out through the vagina as blood and mucus. This cycle is called menstruation.
Q71. What is the difference between Vasectomy and Tubectomy?
Ans: Vasectomy is the blocking of the Vas Deferens in males. Tubectomy is the blocking of the Fallopian tubes in females.
Q72. Why is prenatal sex determination banned?
Ans: To prevent female foeticide and maintain a healthy sex ratio in society.
Q73. What is fragmentation?
Ans: An asexual reproduction method where the body breaks into pieces, and each piece grows into a new individual (e.g., Spirogyra).
Q74. What is the function of the prostate gland and seminal vesicles?
Ans: They add secretions to the sperm to make semen, which provides nutrition and easier transport for sperms.
Q75. How does the oral contraceptive pill work?
Ans: It changes the hormonal balance of the body to prevent the release of eggs (ovulation).
Q76. What is the role of the flower in plants?
Ans: The flower is the reproductive part of the plant containing male (stamen) and female (pistil) reproductive organs.
Q77. What is tissue culture?
Ans: A technique of growing new plants by removing tissue or cells from the growing tip of a plant in an artificial medium.
Q78. Define Spore Formation.
Ans: A reproduction method where the parent plant produces hundreds of microscopic reproductive units called spores (e.g., Rhizopus/Bread mould).
Q79. Why is variation beneficial to species?
Ans: Variation enables species to adapt to changing environmental conditions, ensuring survival.
Q80. What is the gestation period in humans?
Ans: About 9 months (approx. 280 days).
PART 4: HEREDITY (AND EVOLUTION BRIEF)
Q81. Define Heredity.
Ans: The transmission of characters (traits) from parents to offspring is called heredity.
Q82. Who is known as the Father of Genetics?
Ans: Gregor Johann Mendel.
Q83. What is a Gene?
Ans: A gene is a segment of DNA on a chromosome that codes for a specific protein or character.
Q84. Differentiate between Genotype and Phenotype.
Ans: Genotype is the genetic constitution of an organism (e.g., Tt). Phenotype is the physical appearance of the organism (e.g., Tall).
Q85. What are Alleles?
Ans: Different forms of a gene occupying the same position on a chromosome (e.g., T and t).
Q86. Why did Mendel select the pea plant for his experiments?
Ans: Because pea plants are easy to grow, have a short life cycle, and show distinct contrasting characters.
Q87. State Mendel’s Law of Dominance.
Ans: In a cross between two pure parents differing in a pair of contrasting characters, only one character appears in the F1 generation (Dominant), while the other remains hidden (Recessive).
Q88. What is the Phenotypic ratio of a Monohybrid cross in the F2 generation?
Ans: 3:1 (3 Tall : 1 Dwarf).
Q89. What is the Genotypic ratio of a Monohybrid cross in the F2 generation?
Ans: 1:2:1 (1 TT : 2 Tt : 1 tt).
Q90. What is the Phenotypic ratio of a Dihybrid cross (e.g., Round-Yellow x Wrinkled-Green)?
Ans: 9:3:3:1.
Q91. How is sex determined in human beings?
Ans: By sex chromosomes. Females have XX, and Males have XY. If an egg (X) is fertilized by an X-sperm, it's a girl. If fertilized by a Y-sperm, it's a boy.
Q92. Who determines the sex of the child genetically?
Ans: The Father, because he produces two types of sperms (X and Y), whereas the mother produces only one type of egg (X).
Q93. What is a Dominant Trait?
Ans: A trait that expresses itself in the presence of its contrasting allele (e.g., Tallness T over dwarfness t).
Q94. What is a Recessive Trait?
Ans: A trait that expresses itself only when present in a homozygous condition (e.g., dwarfness tt).
Q95. Define Evolution.
Ans: The gradual change in the heritable characteristics of biological populations over successive generations.
Q96. What are Acquired Traits?
Ans: Traits developed during the lifetime of an individual due to environmental factors or use/disuse (e.g., muscle building). These are not inherited.
Q97. What are Inherited Traits?
Ans: Traits passed from parents to offspring via genes (e.g., eye color, blood group).
Q98. State Mendel’s Law of Segregation.
Ans: During gamete formation, the two alleles for a character separate from each other so that each gamete receives only one allele.
Q99. State Mendel’s Law of Independent Assortment.
Ans: In a dihybrid cross, the inheritance of one pair of traits is independent of the other pair of traits.
Q100. Where are genes located?
Ans: Genes are located on the chromosomes inside the nucleus of a cell.
-- End of Question Bank --