General Science Questions (MCQs) for Competitive Examinations

Notes:
Time required for the organism to eliminate 50 per cent of the total body burden or tissue concentration of chemical is referred to as Half Life Period. A biological half-life or elimination half-life is the time it takes for a substance (drug, radioactive nuclide, or other) to lose one-half of its pharmacologic, physiologic, or radiological activity.

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Mostly medicinal herbs grown from 30 to 90 cm in height. They reach up to 30 cm in diameter.

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Carbon monoxide inhibits the blood’s ability to carry oxygen to body tissues including vital organs such as the heart and brain. When CO is inhaled, it combines with the oxygen carrying haemoglobin of the blood to form carboxy-haemoglobin (COHb). Once combined with the Haemoglobin, that haemoglobin is no longer available for transporting oxygen.

Notes:
The National Viral Hepatitis Control Program aims to combat hepatitis and achieve country wide elimination of Hepatitis C by 2030. Launched on 28 July, 2018, it also aims to achieve significant reduction in the infected population, morbidity and mortality associated with Hepatitis B and C viz. Cirrhosis and Hepato-cellular carcinoma (liver cancer).

Notes:
Bird and snake excretory product is uric acid. Nitrogenous waste is excreted in form of ammonia. In birds and reptiles, uric acid is the major end-product of protein metabolism. It is produced by the liver and excreted by kidney tubules; impaired elimination is an indication of renal disease.

Notes:
Thrombin is a serine protease, an enzyme, that is at the centre of blood clotting process in human beings. It catalyzes the conversion of fibrinogen to fibrin and activates procoagulant factors V, VIII, XI, and XIII. Additionally, when bound to thrombo-modulin, it activates protein C, an anticoagulant zymogen.

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The aorta is the largest artery of the human body. It is an artery that directly arises from the heart itself and descends through the thorax and into the abdomen. All the arteries of the body, save the pulmonary arteries, stem from the aorta or one of its main branches.

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The glomerulus functions as an excretory organ in hemichordates. Soluble wastes are collected from the blood by the glomerulus, lying within the proboscis cavity, and excreted from that cavity through a dorsal pore (an opening on the upper side) to the outside.

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Fermentation is the process by which complex organic compounds, such as glucose, are broken down by the action of enzymes into simpler compounds in the absence of oxygen (anaerobic). Yeasts can convert sugars to alcohol and carbon dioxide by fermentation. Fermentation is used to produce wine, beer, yogurt and other products.

Notes:
The constituents of phloem are Sieve tubes, Companion cells, Phloem parenchyma, Phloem fibres. Tracheids are elongated cells in the xylem of vascular plants that serve in the transport of water and mineral salts. These are elongated narrow tube like cells with hard thick and lignified walls with large cell cavity.