Comprehensive Biology Test 12
551. Common spice “clove” is obtained from which part of the plant ?
Ans: Flower bud
Explanation: Clove is the dried unopened flower bud of the clove tree (Syzygium aromaticum), used as spice and medicine.
552. The final product of starch digestion in the alimentary canal is ?
Ans: Maltose
Explanation: Enzymes like amylase break starch into maltose, a simpler sugar that later converts into glucose for absorption.
553. Companion cells in phloem are found in ?
Ans: Angiosperms
Explanation: Companion cells are associated with sieve tubes in angiosperms, helping in translocation of food through the phloem.
554. The rearing of silkworms is called ?
Ans: Sericulture
Explanation: Sericulture is the practice of breeding silkworms to produce silk fibers from their cocoons.
555. Which part of the flower produces pollen grains ?
Ans: Anther
Explanation: The anther, part of the stamen, contains pollen sacs where male gametes (pollen grains) are formed.
556. Carrot is a rich source of which vitamin ?
Ans: Vitamin A
Explanation: Carrots contain beta-carotene, which converts to Vitamin A — essential for vision, growth, and immune function.
557. Toxicology is the study of ?
Ans: Poisons
Explanation: Toxicology deals with the effects, detection, and treatment of poisons in living organisms.
558. Alfalfa is a type of ?
Ans: Grass
Explanation: Alfalfa (Medicago sativa) is a leguminous forage crop rich in protein, often used as animal feed.
559. Which organelle is absent in bacterial cells ?
Ans: Nucleus
Explanation: Bacteria are prokaryotes; they lack a true membrane-bound nucleus, having only a nucleoid region containing DNA.
560. Which metal is a component of Vitamin B12 ?
Ans: Cobalt
Explanation: Vitamin B12 contains cobalt at its core (as cobalamin), vital for red blood cell formation and nerve function.
561. The two richest sources of dietary protein are ?
Ans: Soybean and Groundnut
Explanation: Both soybean and groundnut contain high-quality plant proteins, making them excellent alternatives to animal proteins.
562. How many ear bones are found in humans ?
Ans: Six (three in each ear)
Explanation: Each ear has three tiny bones — malleus, incus, and stapes — that transmit sound vibrations to the inner ear.
563. Animals of phylum Annelida are ?
Ans: Cylindrical worms
Explanation: Annelids are segmented, cylindrical worms like earthworms and leeches, having a true coelom and segmented body.
564. What type of tail is found in sharks ?
Ans: Heterocercal tail
Explanation: In sharks, the upper lobe of the tail is longer than the lower (heterocercal), aiding in upward thrust and balance.
565. Instrument used to measure stem growth rate - Auxanometer
Explanation: Measures growth of plant stems by recording changes in length over time due to cell elongation.
566. Harmful substance in tobacco smoke - Nicotine
Explanation: Nicotine is an addictive alkaloid that affects the nervous system and causes increased heart rate and blood pressure.
567. Pancreas secretes which hormone ? - Insulin
Explanation: Insulin regulates blood sugar levels by converting excess glucose into glycogen for storage in the liver.
568. Yellowish color of cow’s milk is due to - Carotene
Explanation: Carotene is a natural pigment that gives milk a light yellow tint and also serves as a precursor to vitamin A.
569. Transplant between genetically identical individuals - Isograft
Explanation: Isograft occurs between identical twins or clones; since genes are identical, rejection chances are minimal.
570. Lactose is found in - Milk
Explanation: Lactose is a natural sugar (disaccharide) found in milk; it provides energy and aids calcium absorption.
571. Meiosis occurs in - Reproductive cells
Explanation: Meiosis reduces chromosome number by half, forming gametes (sperm and egg) for sexual reproduction.
572. Study of cells is called - Cytology
Explanation: Cytology focuses on cell structure, function, and composition - the basic unit of all living organisms.
573. Proteins are digested by - Protease
Explanation: Protease enzymes break down complex proteins into amino acids, aiding nutrient absorption in the small intestine.
574. Xerophthalmia is caused by deficiency of - Vitamin A
Explanation: Lack of Vitamin A leads to dryness of the eyes, corneal damage, and night blindness.
575. Stomatal opening is based on - Endosmosis
Explanation: Water enters guard cells by endosmosis, making them turgid and opening the stomatal pore for gas exchange.
576. Emulsification means - Breaking fats into small globules
Explanation: Bile salts break large fat droplets into smaller ones, increasing the surface area for enzyme action.
577. Double helix model of DNA was proposed by - Watson and Crick
Explanation: They described DNA as two helical strands joined by complementary base pairs, carrying genetic information.
578. Mendel is famous for - Genetic laws
Explanation: Gregor Mendel discovered inheritance patterns using pea plants, laying the foundation of modern genetics.
579. Exhaled air contains about - 4% carbon dioxide
Explanation: During respiration, cells release CO₂, which is exhaled through lungs, while oxygen is absorbed for metabolism.
580. Percentage of fat in ghee - 99%
Explanation: Ghee is almost pure fat, providing concentrated energy but no proteins or carbohydrates.
581. Sex chromosomes are called - Allosomes
Explanation: Allosomes determine an organism’s sex — XX for females and XY for males in humans.
582. Digestive bag of the cell is - Lysosome
Explanation: Lysosomes contain digestive enzymes that break down worn-out cell parts and foreign substances.
583. Master copy of genetic information - DNA
Explanation: DNA stores hereditary information and controls protein synthesis in all living organisms.
584. Term "Rhizosphere" was given by - Hiltner
Explanation: Rhizosphere refers to the soil region around roots influenced by microorganisms and nutrients.
585. Another name for kneecap - Patella
Explanation: The patella protects the knee joint and helps with leg extension during movement.
586. Main components of food - Fats, Proteins, Carbohydrates
Explanation: These macronutrients supply energy, build body tissues, and support vital biological functions.
587. Green pigment responsible for photosynthesis - Chlorophyll
Explanation: Chlorophyll absorbs sunlight (mainly red and blue light) and converts it into chemical energy for food production.
588. Maximum Conversion of Solar Energy Occurs In:Green Plants
Explanation:
Green plants absorb sunlight through chlorophyll to perform photosynthesis, converting solar energy into chemical energy (carbohydrates).
589. Controlling Environmental Pollution By:
Ans: Preventing Nuclear Explosions, Using Electric Vehicles
Explanation:
Limiting nuclear activities and promoting clean technologies like electric vehicles reduces air, water, and soil pollution.
590. Anticoagulant Substance in Blood:
Ans: Heparin
Explanation:
Heparin prevents blood clotting by inhibiting thrombin and other clotting factors, maintaining smooth circulation.
591. First Person to Use the Term "Gene":
Ans: Johannsen
Explanation:
Johannsen coined the term “gene” in 1909 to describe units of heredity controlling traits in organisms.
592. Carrot Color Due To:
Ans: Carotene
Explanation:
Carotene, a pigment in carrots, gives them their characteristic orange color and acts as a vitamin A precursor.
593 Itai-Itai Disease Caused By:
Ans: Cadmium
Explanation:
Cadmium toxicity, often from contaminated water or rice, causes bone pain, kidney damage, and the Itai-Itai disease.
594. Hairy Seeds Attach To:
Ans: Long Hairs
Explanation:
Seeds with long hairs (e.g., cotton) cling to animals, humans, or wind, aiding in dispersal.
595. Hemoglobin-Like Molecule in Plants:
Ans: Cytochrome
Explanation:
Cytochromes in plant cells transport electrons during cellular respiration, similar to hemoglobin’s oxygen transport in animals.
596. Energy in “Sweetex” Used By Diabetic Patients:
Ans: 5 Calories
Explanation:
Artificial sweeteners like Sweetex provide minimal caloric value, allowing blood sugar control in diabetic diets.
597. Study of Chromosome Morphology Best During:
Ans: Metaphase
Explanation:
Chromosomes are most condensed and visible during metaphase, making it ideal for karyotype analysis.
598. Animal of AB Blood Group:
Ans: Camel
Explanation:
Certain camels exhibit AB blood group characteristics; camelids have unique immunological blood properties.
599. Longest Worm:
Ans: Tapeworm
Explanation:
Tapeworms (cestodes) are parasitic flatworms, some reaching several meters in length inside host intestines.
600. Clones in Animals Obtained By:
Ans: Micropropagation
Explanation:
Cloning involves creating genetically identical organisms or tissues using micropropagation or tissue culture techniques.