General Science Questions (MCQs) for Competitive Examinations

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In algae, sexual reproduction takes place through fusion of two gametes. It is of two types on the basis of the size of gametes : isogamous (where male and female gametes are morphologically similar) and heterogamous (anisogamous and oogamous). Anisogamous fusion happens when gametes are dissimilar in size.

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Oils are unsaturated carbon compounds that have double or triple bonds. Double and triple bonds are easy to be digested or to be broken down into simpler substances. But if a saturated compounds like Vanaspati Ghee are used, it becomes difficult for our body to digest the food as single bonds are not easily broken down into simpler substances by the acids present in our body. Animal fat is a saturated fat in which the fatty acid chains have all or predominantly single bonds. It is made of long chains of carbon (C) atoms. Saturated fatty acids are straight-chain organic acids with an even number of carbon atoms. They raise the serum LDL cholesterol concentration when they are consumed in the diet. So, they are harmful for our health.

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The platypus, also known as the duck-billed platypus, is a semi-aquatic egg-laying mammal endemic to eastern Australia. It is one of the five extant species of monotremes, the only mammals that lay eggs instead of giving birth.

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Exobiology is the branch of biology that deals with the search for extraterrestrial life and the effects of extraterrestrial surroundings or outer space on living organisms.
 The primary goal of exobiological research is to reach a better understanding of the processes leading to the origin, evolution and distribution of life on cosmos within the context of cosmic evolution.

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The abundant enzyme in the living world is Rubisco. It is a key regulator of non-steady state of photosynthesis. Ribulose-1,5-bisphosphate carboxylase oxygenase, most commonly known by the shorter name RuBisCO, is an enzyme that catalyses the first major step of carbon fixation, a process by which atmospheric carbon dioxide and water are converted to energy-rich molecules such as glucose, using sunlight.

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The term fine particles, or particulate matter 2.5 (PM2.5), refers to tiny particles or droplets in the air that are two and one half microns or less in width. Particles in the PM2.5 size range are able to travel deeply into the respiratory tract, reaching the lungs. Once in lungs, they block alveoli for gaseous exchange.

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Femur (thigh bone) is the longest bone in the human body. It is the upper bone of the leg or hind leg. The head forms a ball-and-socket joint with the hip, being held in place by a ligament within the socket and by strong surrounding ligaments. By most measures the femur is the strongest bone in the body.

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Silicon is a chemical element with the symbol Si and atomic number 14. Over 90 percent of the Earth’s crust is composed of silicate minerals. Highly purified silicon is used in semiconductor electronics in manufacturing microships.

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White phosphorus is the most reactive form of phosphorus. It is made up of discrete P4 tetrahedra which are subjected to very high angular strain as the angles is 60 degrees. This high angular strain makes white phosphorus unstable and highly reactive. It ignites spontaneously at about 50°C, and at much lower temperatures if finely divided. Therefore, it is stored in cold water in brown coloured bottles.

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The salts of hydrogen cyanide (Chemical name of Prussic acid) are known as cyanides.It is a colorless, extremely poisonous and flammable liquid that boils slightly above room tempe-rature, at 25.6°C. It is pro-duced on an industrial scale and is a highly valuable pre-cursor to many chemical com-pounds ranging from polymers to pharmaceuticals.