UPSC 2011 Science and Technology Questions with Answers

Explanation

Trans fatty acids (TFA) or trans fats are a form of unsaturated fat and come in both natural and artificial forms. Trans fats are the most harmful type of fats which can cause an adverse effect on a human body than any other dietary constituent.

Statement 1 is correct: Artificial trans fats are generated through an industrial process that adds hydrogen to liquid vegetable oils to form them more solid. That is hydrogen is made to react with the oil to produce fats that resemble pure ghee or butter. If items do not contain trans-fats, it means the food products are not made out of hydrogenated oils and animal fats/oils.

Statement 2 is incorrect: This is incorrect because not all animal fats contain trans fats. While small amounts of naturally occurring trans fats are found in some animal products, the harmful trans fats that raise cardiovascular risks are primarily from industrial hydrogenation, not from natural animal fats.

Statement 3 is correct: If items do not contain trans fats, it suggests that the oils used are less likely to harm the cardiovascular health of consumers, as oils associated with trans fats typically raise LDL (bad) cholesterol and lower HDL (good) cholesterol, contributing to plaque buildup in arteries and increasing the risk of heart attacks and strokes.

Explanation

Statement 1 is correct: An LED is a type of semiconductor light source with two leads. It is a p-n junction diode, which when turned on emits light. A fluorescent lamp is a low-pressure mercury-vapour gas-discharge light. In a CFL, an electric current is driven through a tube containing argon and a small amount of mercury vapor. This generates invisible ultraviolet light that excites a fluorescent coating (called phosphor) on the inside of the tube, which then emits visible light.

Statement 2 is incorrect: LED bulbs are much more efficient than CFL bulbs in terms of power consumption and life years.

Statement 3 is correct: LED bulbs consume less power as compared to CFL. LED bulbs are expensive as compared to CFL bulbs. LED bulbs are much more efficient than CFL bulbs.

Explanation

Aspartame is a non-saccharide artificial sweetener approximately 200 times sweeter than sucrose, and is commonly used as a substitute of sugar in foods and beverages. The commercial names for it are NutraSweet, Equal, and Canderel. It is a methyl ester of the aspartic acid / phenylalanine dipeptide. Since Aspartame is several times sweeter than table sugar, hence food items made with small quantities of aspartame yield fewer calories on oxidation.

Explanation

Oilzapper is an eco-friendly technology for oil sludges and oil spills remediation. Oilzapping is the new technique using bacteria to get rid of oil spills. It is a bioremediation technique that involves the use of oil zapping bacteria. In essence, Oilzapper is a concoction of five distinct bacterial strains that have been immobilised and combined with a carrier substance (powdered corn cob). The Oilzapper consumes the hydrocarbon molecules found in crude oil and oily sludge, a dangerous hydrocarbon waste product produced by oil refineries, and transforms them into harmless CO₂ and water. This is exactly what its witty name implies.

Explanation

The blood group of the couple is AB Positive and O Negative. So their biological sons will have either blood group A or B. Thus we can infer that the blood group of the adopted son will be O.

Explanation

Statement 1 is correct: DVD stands for "Digital Versatile Disk" or "Digital Video Disc". It is a type of digital optical disc storage that can hold any kind of digital data but is frequently used to store pictures, audio, and video in standard definition. Blu-ray Disc is a digital disc storage format similar to CD and DVD, that is designed to record and play a large amount of data with high-definition quality.

Statement 2 is correct: Blu-ray Disc media include these features: 50GB capacity - Each disc can hold more than 10 standard DVDs.

Statement 3 is incorrect: The size of the Blu-ray disc is 120 millimetres in diameter with 1.2 millimetres thickness, which is the same as the size of a CD and DVD.

Explanation

The tissue just beneath the bark called the phloem layer is in charge of moving food produced by photosynthesis from the leaves to the roots. This process is called girdling, and it is fatal to trees because it disrupts the transport of nutrients. Without this nourishment, the roots eventually perish and stop supplying the leaves with water and nutrients. Later, the leaves wither. Because its roots are starved of vitality, a tree that has had its bark removed in a circular pattern all around near its base gradually dries up and dies.

Explanation

Statement 1 is incorrect: The presence of ions, and not ozone, in the Ionosphere is responsible for radio communication. Ozone is primarily present in the Stratosphere and not in the Ionosphere.

Statement 2 is incorrect: They have frequencies from 300 GHz to as low as 3 kHz and corresponding wavelengths from 1 millimetre to 100 kilometres. They have a long range of wavelengths, so they can have very small wavelengths as well.

Explanation

Bt Brinjal is the first Genetically Modified food crop in India that has reached the approval stage for commercialization. Bt Brinjal is a genetically modified (GM) crop created by inserting Cry1Ac gene from the soil bacterium Bacillus thuringiensis into Brinjal. Brinjal plants now have resistance to lepidopteran pests such the Brinjal Fruit and Shoot Borer (Leucinodes orbonalis) and Fruit Borer as a result of the gene’s insertion (Helicoverpa armigera).

Explanation

The carbon cycle is a natural process that involves the movement of carbon between the atmosphere, oceans, soil, rocks, and living organisms. Respiration, decay of organic matter, volcanic action, fossil fuel combustion, deforestation, ocean-atmosphere exchange adds carbon to the cycle. All living organisms (plants, animals, and microorganisms) respire and breaking down glucose and oxygen to release energy, CO₂, and water. This process adds carbon dioxide to the atmosphere. When dead plants, animals, and other organic materials decompose microbes break them down. During decomposition CO₂ and methane (CH₄) are released into the atmosphere. Volcanic eruptions release stored carbon dioxide from the Earth’s mantle into the atmosphere. This is a natural source of CO₂ emissions. During photosynthesis plants, algae, and some bacteria absorb CO₂ from the atmosphere and use sunlight to convert it into glucose and oxygen. This process removes carbon dioxide from the atmosphere rather than adding it.