General Science Questions (MCQs) for Competitive Examinations

Notes:
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.

Notes:
Taenia is a genus of tapeworm that includes some important parasites of livestock. Members of the genus are responsible for taeniasis and cysticercosis in humans. There are more than 100 species recorded. They are morphologically characterized by a ribbon-like body composed of a series of segments called proglottids with proximal mouth called scolex.

Notes:
A thick vein seen in the middle of the leaf is called the midrib. Pinnately veined leaves have one large central vein, called the midrib, which extends from the base of the blade to its tip. Other large veins branch off on each side of the midrib. The leaves of beech, birch, and elm trees have such a vein pattern.

Notes:
Plants obtain nitrogen through their roots. In the soil, nitrifying bacteria change ammonia into nitrite (NO2 –) and then into nitrate (NO3 –), this process is known as nitrification. Furthermore, plants also absorb nitrogen in an organic form. Several organic compounds (compounds containing carbon) constitute the organic fraction of nitrogen in the soil. The organic matter in the soil exists as decomposing plant and animal residues, relatively stable decomposition-resistant compounds, and humus. The abundance of various forms of nitrogen can be altered by plant roots through the change in pH and secretion of organic compounds or oxygen.

Notes:
Cuscuta (Dodder) is a genus of about 100-170 species of yellow, orange or red (rarely green) parasitic plants. Dodders are supremely adapted for a life of plunder and pillage. Reduced in form to scrambling and twining threads, they appear to be completely leafless, although closer inspection reveals tiny scale leaves pressed close to the stems. So, it is a stem parasite.

Notes:
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%).

Notes:
Solitary cymose inflorescence refers to a determinate inflorescence composed of a single flower. Examples include poppy, gardenia (ornamental plant), tulip, etc. Flowers are said to be solitary when the plant bears only one, or when single flowers appear on the ends of lateral branches that are remote from one another.

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Penicillin the so called ‘Wonder drug’ discovered by Alexander Fleming in 1927 is produced from the genus of fungi “Penicillia”. All penicillin are â-lactam antibiotics and are used in the treatment of bacterial infections caused by susceptible, usually Grampositive organisms.

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Smallpox was an infectious disease caused by either of two virus variants, Variola major and Variola minor. After vaccination campaigns throughout the 19th and 20th centuries, the WHO certified the global eradication of smallpox in 1979. Smallpox is one of two infectious diseases to have been eradicated, the other being Rinderpest.

Notes:
When freshwater fish is placed in salt water, the water molecules contained in the fish’s body would pass through the cell membranes of the fish, causing the fish to lose water by osmosis. This sudden change in the molecular makeup of the fish would cause the fish to undergo severe dehydration followed by death.