Comprehensive Biology Test 1
51. Enzyme Digesting Milk Protein:
Ans: Rennin
Explanation:
Rennin (chymosin) coagulates milk by converting casein into curds and whey. It aids protein digestion in infants and is used in cheese production.
52. Who Proposed Five Kingdom Classification:
Ans: Robert Whittaker
Explanation:
Whittaker proposed the five-kingdom system: Monera, Protista, Fungi, Plantae, and Animalia. This classification is based on cell structure, nutrition, and complexity.
53. Discoverer of Blood Groups:
Ans: Karl Landsteiner
Explanation:
Landsteiner discovered ABO blood groups in 1901. His work enabled safe blood transfusions by matching compatible blood types and preventing transfusion reactions.
54. Excretion of Water, Fats, and Metabolic Wastes:
Ans: Kidney
Explanation:
The kidney filters blood to remove metabolic wastes, excess water, and salts. It forms urine, maintaining homeostasis, electrolyte balance, and removing toxic substances.
55. Cultivable Land Left Fallow:
Ans: Cultivable Wasteland
Explanation:
Land suitable for farming but left uncultivated is called cultivable wasteland. Reasons include poor irrigation, soil fertility issues, or agricultural planning to allow soil recovery.
56. Meaning of Amphibian:
Ans: “Two Lives”
Explanation:
Amphibians live both in water and on land during their life cycle. They have gills in early stages and lungs as adults, adapting to dual environments.
57. Region with Maximum Eucalyptus Trees in India:
Ans: Mizoram Hills
Explanation:
Eucalyptus is widely planted in Mizoram for timber, fuelwood, and paper industry due to fast growth and adaptability to hilly and subtropical regions.
58. Brain Part Associated with Motor Skills:
Ans: Frontal Lobe
Explanation:
The frontal lobe of the brain controls voluntary movements, motor coordination, problem-solving, planning, and skill learning, making it crucial for both physical and cognitive functions.
59. Folds in Empty Stomach Mucosa:
Ans: Rugae
Explanation:
Rugae are folds in the stomach lining that allow expansion after food intake. They increase surface area and help in mixing food with digestive enzymes.
60. Lockjaw Disease (Tetanus) Another Name:
Ans: Tetanus
Explanation:
Tetanus, caused by Clostridium tetani, is characterized by muscle stiffness and spasms, particularly in jaw muscles (lockjaw). Vaccination prevents this often-fatal bacterial disease.
61. Lockjaw Disease (Tetanus) Another Name:
Ans: Tetanus
Explanation:
Tetanus is caused by Clostridium tetani. Its toxin causes muscle stiffness and spasms, especially in jaw muscles, which is why it is called lockjaw. Vaccination prevents it.
62. Chemicals Released by Animals to Attract Same Species:
Ans: Pheromones
Explanation:
Pheromones are chemical signals secreted by animals to communicate with members of the same species, often for mating, marking territory, or social organization.
63. Substance Used to Reduce High Fever:
Ans: Antipyretic
Explanation:
Antipyretics, like paracetamol, reduce body temperature during high fever by acting on the hypothalamus, helping the body return to normal temperature and providing relief.
64. Where Digestion Begins in Humans:
Ans: Mouth
Explanation:
Digestion starts in the mouth, where mechanical chewing and enzymatic action by saliva (amylase) break down carbohydrates into simpler sugars for further digestion.
65. Normal Heartbeat of a Healthy Human Per Minute:
Ans: 72 beats per minute
Explanation:
A healthy adult’s heart beats about 72 times per minute at rest. This rate supplies adequate oxygen and nutrients through blood circulation throughout the body.
66. Smallest Bone in the Human Body:
Ans: Stapes (in the ear)
Explanation:
The stapes is the smallest bone in the human body, located in the middle ear. It transmits sound vibrations from the incus to the inner ear efficiently.
67. Element Absorbing Chlorophyll Components:
Ans: Magnesium
Explanation:
Magnesium is the central atom in chlorophyll. It plays a key role in capturing light energy for photosynthesis, enabling plants to produce food.
68. Structural and Functional Unit of Nervous System:
Ans: Neuron
Explanation:
Neurons are specialized cells transmitting electrical signals. Each consists of a cell body, dendrites, and an axon, enabling communication between the brain, spinal cord, and body.
69. Cobalt Found In:
Ans: Vitamin B12
Explanation:
Cobalt is an essential trace element present in vitamin B12. It is crucial for red blood cell formation, neurological function, and DNA synthesis in humans.
70. Sugar Found in Milk:
Ans: Lactose
Explanation:
Lactose is the primary sugar in milk. It provides energy, helps calcium absorption, and is broken down by the enzyme lactase into glucose and galactose.
71. Blood Flow When Left Ventricle Contracts:
Ans: Aorta
Explanation:
During contraction of the left ventricle, oxygenated blood is pumped into the aorta, from where it is distributed throughout the body via systemic circulation.
72. Smallest Cells in Human Body:
Ans: Red Blood Cells (Erythrocytes)
Explanation:
Red blood cells are small, biconcave, and lack nuclei. They efficiently transport oxygen via hemoglobin to tissues and carbon dioxide to lungs for excretion.
73. Duration of One Heartbeat:
Ans: 0.8 seconds
Explanation:
One cardiac cycle lasts approximately 0.8 seconds in a healthy adult. It includes atrial contraction, ventricular contraction, and relaxation phases.
74. Plant Cell That Stores Cellular Reserve Substances:
Ans: Idioblast
Explanation:
Idioblasts are specialized plant cells that store unusual substances such as crystals, oils, or tannins, helping in storage, defense, or structural support.
75. Life-Saving Hormones Called:
Ans: Adrenal Hormones
Explanation:
Adrenal hormones, like adrenaline and cortisol, regulate stress response, metabolism, blood pressure, and electrolyte balance. They help the body respond to emergencies and maintain homeostasis.
76. Largest Bird in the World:
Ans: Ostrich
Explanation:
The ostrich is the largest living bird. Flightless and native to Africa, it uses strong legs for running and lays the largest eggs among all birds.
77. Clitellum Found in:
Ans: Earthworm
Explanation:
The clitellum is a thickened, glandular segment in earthworms that secretes mucus to form a cocoon for eggs, aiding reproduction and protecting developing embryos.
78. Maximum Permissible Total Hardness in Drinking Water:
Ans: 300 mg/L as CaCO₃
Explanation:
Total water hardness, caused by calcium and magnesium salts, should not exceed 300 mg/L. Hardness beyond this affects taste, soap efficiency, and can cause scale deposits.
79. Enzyme Digesting Milk Protein:
Ans: Rennin (Chymosin)
Explanation:
Rennin, produced in the stomach, coagulates milk by converting casein into curds and whey. It helps infants digest milk proteins and is used in cheese production.
80. Who Proposed Five Kingdom Classification:
Ans: Robert Whittaker
Explanation:
Whittaker proposed classifying organisms into five kingdoms: Monera, Protista, Fungi, Plantae, and Animalia, based on cell structure, mode of nutrition, and complexity.
90. Goiter Disease Caused By:
Ans: Iodine Deficiency
Explanation:
Goiter is an enlargement of the thyroid gland due to insufficient iodine in diet. It is common in mountainous regions with iodine-poor soil.
91. Hapten:
Ans: Incomplete Antigen
Explanation:
Haptens are small molecules that cannot trigger immune response alone. When attached to larger carriers, they elicit antibody production, playing a role in allergy and immunology studies.
92. Animals Growing in Air:
Ans: Epiphytic
Explanation:
Epiphytic organisms grow on other plants in air, obtaining nutrients from rain, dust, or air, without parasitizing the host. Examples include orchids and ferns.
93. Use of Gypsum:
Ans: To Improve Podzol Soil
Explanation:
Gypsum (CaSO₄·2H₂O) is applied to acidic podzol soils to reduce acidity, improve soil structure, increase water retention, and enhance fertility for better crop yield.
94. Hemoglobin Is a Compound of:
Ans: Protein
Explanation:
Hemoglobin is a protein containing heme and globin chains. It binds oxygen in lungs and releases it to tissues, essential for cellular respiration and energy production.
95. Form in Which Carbohydrates Are Stored in Body:
Ans: Glycogen
Explanation:
Carbohydrates are stored as glycogen in liver and muscles. It acts as a reserve energy source, rapidly broken down into glucose when the body requires energy.
96. AIDS Virus Destroys:
Ans: Lymphocytes (T-helper Cells)
Explanation:
HIV infects and destroys CD4+ T-helper lymphocytes, weakening the immune system and making the body susceptible to opportunistic infections, leading to AIDS.
97. Study of Tissues Called:
Ans: Histology
Explanation:
Histology is the study of animal and plant tissues under microscopes. It helps understand structure, function, and pathology of cells in various organs.
98. Non-Green Parasitic Plants in Plant Kingdom:
Ans: Fungi-like
Explanation:
Non-green parasitic plants lack chlorophyll and depend on other plants for nutrition. Examples include Cuscuta and Rafflesia, which absorb nutrients from host plants.
99. First Cloned Sheep Name:
Ans: Dolly
Explanation:
Dolly was the first mammal cloned from an adult somatic cell in 1996 using nuclear transfer, marking a breakthrough in reproductive biotechnology.
100. Tear Secretion During Crying Caused By:
Ans: Lacrimal Glands
Explanation:
When a person cries, the lacrimal glands secrete tears. Tears lubricate the eyes and flush out irritants, triggered by emotions or reflex responses.