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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Photorespiration is a special type of respiration shown by many green plants when they are exposed to light. Glycolate (glycolic acid) is the chief metabolite of photorespiration and also its substrate. Other important metabolites are the amino acids glycine and serine.

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Weil’s disease is a severe form of leptospirosis, a type of infection caused by Leptospira bacteria. The classic form of severe leptospirosis is known as Weil’s disease, which is characterized by liver damage (causing jaundice), kidney failure, and bleeding.

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A heterogeneous mixture is a mixture in which the composition is not uniform throughout the mixture. A suspension is a heterogeneous mixture in which solute-like particles settle out of a solvent-like phase sometime after their introduction. Examples of suspensions are: fine sand or silt in water or tomato juice.

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When a volume of air at a given temperature holds the maximum amount of water vapour, the air is said to be saturated. When relative humidity reaches 100 percent or is saturated, moisture will condense, meaning the water vapor changes to liquid droplets.

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Salt is produced from the evaporation of seawater. Sea water contains a large amount of common salt and the salts of other metals dissolved in it. Near the seashore, the sea water is collected in shallow pits and allowed to evaporate in sunshine. In a few days, the water evaporates, leaving behind salt.

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Rock salt is the mineral (natural) form of sodium chloride (NaCl). It has high quantities of phosphorous, calcium, potassium, iron, magnesium, zinc, selenium, copper, bromine, zirconium and iodine. All of these minerals occur naturally.

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Landfills, Incineration, Pyrolysis and Gasification are methods of disposing of solid waste which cannot be reused or recycled.

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Chloroform can be used as Anaesthetic. Chloroform (CHCl3) on heating with silver powder undergoes dehalogenation to form Ethyne. It is also an important source for producing foxic phosgene gas.

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Methane is the most common gas that can cause explosions in coal mines. Methane is a colorless and odorless gas that is highly flammable and can easily be ignited by a spark or flame. When methane accumulates in high concentrations in the air in a coal mine, it can create a risk of explosion. This is why it is important for miners to monitor methane levels and take steps to prevent it from reaching dangerous levels.