Comprehensive Biology Test 9
401. Largest bird in the world - Ostrich.
Explanation: Ostriches are flightless African birds, the tallest and heaviest, known for running fast.
402. Kidney stone in humans is made of - Calcium oxalate.
Explanation: Crystallized calcium oxalate forms hard deposits (stones) in kidneys, causing pain and urinary problems.
403. Discoverer of cholera bacteria - Robert Koch.
Explanation: German scientist Koch identified Vibrio cholerae as the causative organism of cholera.
404. Sterilization in males is called - Vasectomy.
Explanation: Vasectomy involves cutting or sealing vas deferens to prevent sperm release during ejaculation.
405. Hormone that stimulates heartbeat - Thyroxine.
Explanation: Thyroxine (from thyroid gland) increases metabolism and heart rate by regulating oxygen use in cells.
406. Number of cartilages in human larynx - Nine.
Explanation: The larynx (voice box) has nine cartilages including thyroid, cricoid, and epiglottis for voice and airway protection.
407. Genetically resistant organisms are called - Recalcitrant.
Explanation: Recalcitrant species naturally resist microbial attack or genetic modification due to strong defense mechanisms.
408. Most endangered top predator of Asia - Dhole.
Explanation: The Asiatic wild dog (Cuon alpinus) is critically endangered due to habitat loss and disease.
409. Scavengers of the Earth - Bacteria and fungi.
Explanation: These decomposers recycle nutrients by breaking down dead plants and animals into simpler substances.
410. Alzheimer’s disease affects - Brain.
Explanation: Alzheimer’s causes degeneration of neurons in the brain, leading to memory loss and confusion.
411. Harmful substances produced by pathogens - Toxins.
Explanation: Pathogenic microbes secrete toxins that damage host tissues and cause diseases.
412. Number of chambers in frog’s heart - Three.
Explanation: Frogs have two atria and one ventricle, allowing partial mixing of oxygenated and deoxygenated blood.
413. Leaving land uncultivated for some years - Fallowing.
Explanation: Fallowing restores soil fertility by allowing natural processes to replenish nutrients.
414. Cholesterol is absent in - Groundnut oil.
Explanation: Cholesterol is found only in animal fats, not in plant-based oils like groundnut oil.
415. Insufficient blood supply to body tissues - Ischemia.
Explanation: Ischemia reduces oxygen delivery, leading to tissue damage or heart attack.
416. International Commission on Zoological Nomenclature established - 1895.
Explanation: It standardizes rules for naming animal species globally to avoid confusion.
417. Basic characteristic of living organisms - Respiration.
Explanation: Respiration allows living beings to release energy from food for cellular activities.
418. Father of Medicine - Hippocrates.
Explanation: Hippocrates, a Greek physician, introduced scientific methods in medicine and ethical medical practice.
419. Cells with shortest life span - Intestinal cells.
Explanation: Intestinal epithelial cells renew every few days due to constant wear and digestion.
420. Bees are used for - Apiculture.
Explanation: Apiculture (beekeeping) produces honey, wax, and aids in pollination.
421. Protein digestion occurs in - Small intestine.
Explanation: Enzymes like trypsin and peptidase break proteins into amino acids for absorption.
422. Pathogenic bacteria secrete - Antigens.
Explanation: Antigens trigger immune response; body forms antibodies to neutralize them.
423. Insulin is secreted by - Pancreas.
Explanation: Pancreatic β-cells produce insulin, maintaining blood glucose balance.
424. Language used for scientific naming of organisms - Latin.
Explanation: Latin ensures universal recognition and consistency in biological classification.
425. Master gland of human body - Pituitary gland.
Explanation: The pituitary controls other endocrine glands by secreting hormones like GH, TSH, and FSH.
426. Air pollution particles damaging vital organs are - PM 2.5.
Explanation: PM2.5 are fine particles that penetrate lungs and bloodstream, causing respiratory and heart diseases.
427. Dialysis works on - Diffusion principle.
Explanation: Dialysis removes waste from blood by allowing small molecules to pass through a semi-permeable membrane.
428. Anaemia is caused by deficiency of - Iron.
Explanation: Lack of iron reduces hemoglobin, leading to fatigue and pale skin.
429. Reflex actions are controlled by - Spinal cord.
Explanation: The spinal cord quickly processes reflexes without involving the brain.
430. Vitamin B6 deficiency in men causes - Anaemia.
Explanation: Vitamin B6 is vital for hemoglobin synthesis; its deficiency reduces red blood cell production.
431. Weight of kidney - 150 grams
Explanation: A normal human kidney weighs about 150 g, helping filter blood, remove waste, and balance body fluids.
432. Main protein in milk - Casein
Explanation: Casein forms about 80% of milk protein; it provides amino acids and calcium, essential for growth and bone strength.
433. Part with most bones - Fingers
Explanation: Fingers contain 14 phalanges in each hand; thus, they have the highest number of small bones in the body.
434. Vitamin role – Synthesis of Prothrombin
Explanation: Vitamin K helps synthesize prothrombin, a protein essential for blood clotting and preventing excessive bleeding.
435. Tadpole breathes through – External gills
Explanation: Newly hatched tadpoles have external gills for respiration, which later change into lungs as they mature into frogs.
436. Biodiesel mostly produced by – Euphorbiaceae
Explanation: Euphorbia plants (like Jatropha) in the Euphorbiaceae family yield oil-rich seeds used for making biodiesel fuel.
437. Food transport in plants – By Phloem
Explanation: Phloem carries prepared food (mainly sucrose) from leaves to other plant parts through translocation.
438. Lactose found in – Milk
Explanation: Lactose is a natural sugar in milk, composed of glucose and galactose, providing energy for infants.
439. Bile secreted by – Liver
Explanation: The liver produces bile, stored in the gallbladder, which helps digest fats in the small intestine.
440. Curcumin extracted from – Turmeric
Explanation: Curcumin is the yellow pigment in turmeric with strong antioxidant and anti-inflammatory properties.
441. Controller of heartbeat – Pacemaker
Explanation: The sinoatrial node acts as the heart’s natural pacemaker, generating impulses that regulate heartbeat rhythm.
442. Platelets die in – Spleen
Explanation: The spleen destroys old or damaged platelets and red blood cells, maintaining healthy blood cell balance.
443. Pollution monitor organism – Lichen
Explanation: Lichens are sensitive to air pollutants like sulfur dioxide, making them natural indicators of air quality.
444. Air pollution increases when ventilation coefficient – >6000 m²/s
Explanation: Higher ventilation coefficient (>6000 m²/s) disperses pollutants quickly, while lower values cause accumulation and poor air quality.
445. Meningitis affects – Brain
Explanation: Meningitis is inflammation of the brain and spinal cord membranes, caused by bacteria or viruses.
446. Bile is – Yellow-green alkaline fluid
Explanation: Bile is an alkaline digestive fluid that emulsifies fats, aiding lipid digestion and absorption.
447. Lac used for sealing produced by – Insect
Explanation: Lac is a resin secreted by Laccifer lacca insects, used in polish and sealing wax.
448. Hashish obtained from – Stem and male inflorescence exudate
Explanation: Hashish is a resinous exudate from stems and flowers of the Cannabis plant, containing psychoactive compounds.
449. Smallest cell – Mycoplasma
Explanation: Mycoplasma are the smallest living cells (0.1 µm), lacking a cell wall but capable of independent growth.
450. Disease with high blood sugar – Diabetes Mellitus
Explanation: In diabetes, insufficient insulin causes elevated blood glucose, leading to fatigue and other health issues.