General Science Questions (MCQs) for Competitive Examinations

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Because of the screening effect, the net positive charge experienced by the electron from the nucleus is lowered and is known as effective nuclear charge. Effective nuclear charge experienced by the orbital decreases with increase of azimuthal quantum number(l).

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All metal carbonates and hydrogen carbonates react with acids to give a corresponding salt, carbon dioxide and water. Limestone, chalk and marble are different forms of calcium carbonate.

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The brain’s limbic system controls emotional expression through the hypothalamus, which has control over the body’s emotional responses systems. The hypothalamus is responsible for regulating hunger, thirst, response to pain, levels of pleasure, sexual satisfaction, anger and aggressive behavior, etc. It also regulates pulse, blood pressure, breathing, and arousal in response to emotional circumstances.

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Keratin is a family of fibrous structural proteins that is the key structural component of hair and nails. It is also the key structural material making up the outer layer of human skin. Besides, it provides the necessary strength and toughness for masticatory organs, such as the tongue.

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Mitochondria is an organelle found in large numbers in most cells, in which the biochemical processes of respiration and energy production occur. It is for this reason that mitochondria are often referred to as the powerhouses of the cell mitochondria also play a key role in the ageing process as well as in the onset of degenerative disease.

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Milk is a poor source of ascorbic acid (Vitamin C). It contains about 1 mg ascorbate per 100 g. Even the little Vitamin C is usually destroyed when the milk is heat treated. Milk as a complete food contains most of the esential nutrients except are vitamin C and iron.

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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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Blubber is a thick layer of vascularized adipose tissue found under the skin particularly whales inhabiting of Arctic ocean. It’s presence insulate their body from ice cold. The energy stored in blubber includes both proteins (mostly collagen) and fats (mostly lipids). Blubber covers the entire body of animals such as seals, whales, and walruses—except for their fins, flippers, and flukes. Whaling largely targeted the collection of blubber: whalers rendered it into oil in try pots, or later, in vats on factory ships. The oil could serve in the manufacture of soap, leather, and cosmetics. Whale oil was used in candles as wax, and in oil lamps as fuel.

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The plastid is a major double-membrane organelle found in the cells of plants. Plastids are the site of manufacture and storage of important chemical compounds used by the cell. Plastids often contain pigments used in photosynthesis, and the types of pigments present can change or determine the cell’s colour.

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In menstrual cycle 19-21 days stands for the fertilizing period also called danger period. After ovulation on 14th day chances of contraption are at their highest with well developed endometrium for implantation. This is the time in the menstrual cycle when progesterone should be at its peak for the month and when estrogen should be at the height of its luteal plateau.