Biology MCQs

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A stem cell is a cell with the unique ability to develop in any of the type of cell. In the future they may be used to replace cells and tissues that have been damaged or lost due to disease.

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The cultivation of Jatropha curcas on wastelands has a potential to generate biofuel in large quantities. It is a species of flowering plant in the spurge family called Euphorbiaceae, that is native to the American tropics, most likely in Mexico and Central America.

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The human musculoskeletal system consists of human skeleton, bones attached to other bones with joints and skeletal muscle attached to the skeleton by tendons. It permits movement of the body, maintains posture and circulates blood throughout the body.

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Thrombin is a naturally occurring enzyme that converts fibrinogen into fibrin, which is an integral step in clot formation. Ca2+ is essential for both activation and action of thrombin.

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99% of body’s calcium is stored in Bones and teeth. The remainder of the calcium is present in blood, extracellular fluid, muscle, and other tissues. It plays a role in mediating vascular contraction and vasodilation, muscle contraction, nerve transmission, and glandular secretion.

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Sucralose is an artificial sweetener. The majority of ingested sucralose is not broken down by the body and therefore it is non-caloric. Sucralose is approximately 600 times as sweet as sucrose (table sugar), twice as sweet as saccharin, and 3 times as sweet as aspartame. It is stable under heat and over a broad range of pH conditions. Therefore, it can be used in baking or in products that require a longer shelf life. The commercial success of sucralose-based products stems from its favorable comparison to other low-calorie sweeteners in terms of taste, stability, and safety. It is used because it is a no-calorie sweetener, and does not promote dental cavities, is safe for consumption by diabetics, and does not affect insulin levels.

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Chlorophylla-a is the primary pigment for photosynthesis in plants. Chlorophyll a is a specific form of chlorophyll used in oxygenic photosynthesis. It absorbs most energy from wavelengths of violet-blue and orange-red light.

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Under suitable conditions, a single cell grows into a colony of cells on agar medium. The resulting population of genetically identical cells derived from a single parent cell is called a clone.

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Spiders, mites, scorpions, and several related groups are not insects, but belong to the arthropod class Arachnida. About 15 families of spiders are frequently encountered in crops, where they provide benefit as natural control agents.

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Vitamins are classified into two broad categories, water soluble (vitamins B complex and C) and fat soluble (vitamins A,D,E and K).
Extra info: Excess intake of fat soluble vitamins leads to toxicity and poses greater risk.