General Science Questions (MCQs) for Competitive Examinations

Notes:
Chemical weapons are called “poorman’s bomb”. These cause catastrophic damage, and are easy to produce. Sarin is a colorless and odourless agent, and is extremely potent. It was used in Damascus in 2013. Mustard Gas is possibly the most commonly used chemical agent and gets its name from the distinctive odour of rotten mustard. It is less potent and usually only 5 to 10 percent people exposed to it usually die. It was widely used during Second World War. VX is a nerve agent which is odourless and appears as brownish oily substance.

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Biofortification is the breeding crops to increase their nutritional value. This can be done either through conventional selective breeding or genetic engineering. Biofortification differs from ordinary fortification because it focuses on making plant foods more nutritious as the plants are growing, rather than having nutrients added to the foods when they are being processed.

Notes:
The chief cells of the stomach secrete enzymes for protein breakdown (inactive pepsinogen and rennin). Hydrochloric acid activates pepsinogen into the enzyme pepsin, which then helps digestion by breaking the bonds linking amino acids, a process known as proteolysis.

Notes:
A heart attack occurs when blood flow to a part of your heart is blocked for a long enough time that part of the heart muscle is damaged or dies. The medical term for this is myocardial infarction. Most heart attacks are caused by a blood clot that blocks one of the coronary arteries. The coronary arteries bring blood and oxygen to the heart. If the blood flow is blocked, the heart is starved of oxygen and heart cells die.

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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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Tamarind tree (Tamarindus indica), Ashoka tree (Saraca Indica), Indian Coral tree (Erythrina Indica) have ‘Indica’ common in their botanical names. In biology/taxonomy, if a species originates in India, its scientific name sometimes includes “Indica”.

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Smallpox was one of the world’s most devastating diseases known to humanity. The last known natural case was in Somalia in 1977. It was declared eradicated in 1980 following a global immunization campaign led by the World Health Organization. Smallpox is caused by infection with the variola virus.

Notes:
The transition from dormancy to germination in seeds is a key physiological process during the lifecycle of plants. Abscisic acid (ABA) is the sole plant hormone known to maintain seed dormancy. It acts through a gene expression network involving the transcription factor Abscisic Acid Insensitive 3 (ABI3).

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Bile or gall is a bitter-tasting, dark green to yellowish brown fluid, produced by the liver aids in the process of digestion of lipids in the small intestine. In many species, bile is stored in the gall bladder and upon eating is discharged into the duodenum. Bile is a composition of the following materials: water (85%), bile salts (10%), mucus and pigments (3%), fats (1%), inorganic salts (0.7%) and cholesterol (0.3%).