Biology MCQs

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Turner syndrome is a rare chromosomal disorder characterized by partial or complete loss (monosomy) of one of the X chromosomes that affects females. Individuals with Turner syndrome have only 45 chromosomes, including just a single X chromosome. This monosomic has a chromosome complement of 44 autosomes and one X chromosome (44+XO). The abnormal condition probably originates from exceptional egg or sperm with no X chromosome.

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Jaundice is a yellowish pigmentation of the skin, the conjunctival membranes over the sclerae (whites of the eyes), and other mucous membranes caused by hyperbilirubinemia. Concentration of bilirubin in blood plasma does not normally exceed 1 mg/dL (>17?mol/L). A concentration higher than 1.8 mg/ dL (>30?mol/L) leads to jaundice. Jaundice is often seen in liver disease such as hepatitis or liver cancer.

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When a plant is placed under the fan, the speed of air is increased which leads to high rate of transpiration through the stomata. The increase in the rate of transpiration increases the water absorption also. As by keeping the plants under the fan, the transpiration process is boosted. Therefore, more amount of water and other minerals are absorbed by the plant roots from the soil.

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Robert Hooke (1665) observed a section of cork under his microscope and found its structure resembling a ‘honey comb’. He gave the name ‘cell’ to each of the compartments of the honey comb like structure. Two German biologists, M Schleiden and T Schwann, later proposed the famous cell theory in 1938-39.

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Various components of blood are: Plasma, Erythrocytes (Red Blood Cells), Leucocytes (White Blood Cells) and Thrombocytes/Platelets. Monocytes, also known as macrophages, are the largest blood cells in most mammals, measuring 10-15 cm in diameter. They are leucocytes. Their nuclei are kidney-shaped and cytoplasm is abundant.

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Gymnosperm are flowerless plant that produces cones and seeds. The term gymnosperm literally means “naked seed”, as gymnosperm seed are not encased within an ovary. Rather they sit exposed on the surface of the leaf like structures called bracts.

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Zika virus (ZIKV) is a member of the virus family Flaviviridae. It is spread by daytime-active Aedes mosquitoes, such as A. aegypti and A. albopictus. Its name comes from the Zika Forest of Uganda, where the virus was first isolated in 1947. Zika virus is related to the dengue, yellow fever, Japanese encephalitis, and West Nile viruses.

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Alveoli are the small balloon-like sacks of 200– 500 ?m diameter, making up a vital part of the respiratory zone of the lungs. Each alveolus (singular) plays an important role in letting oxygen and carbon dioxide move into and from the blood stream during inhalation and exhalation. he balloon-shaped alveoli cover approximately 70 square meter area within the lungs, with this wide surface area contributing towards a more efficient gas exchange.

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The cerebellum is important for making postural adjustments in order to maintain balance. Through its input from vestibular receptors and proprioceptors, it modulates commands to motor neurons to compensate for shifts in body position or changes in load upon muscles. So, it controls the maintenance of posture, balance and equilibrium.

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Mangifera indica is commonly known as mango. It is a species of flowering plant in the sumac and poison ivy family Anacardiaceae. It is found in the wild in Bangladesh, India and Pakistan where it is indigenous. It is the national fruit of India, Pakistan and the Philippines.