Previous Year UPSC Questions

Explanation

Statement (a) is correct: Starch and cellulose are both found in plants. Starch serves as an energy reserve and cellulose is a structural component of plant cell walls. Statement (b) is correct: Both starch and cellulose are polymers made up of repeating units (monomers) of glucose. Starch and cellulose are polysaccharides Statement (c) is incorrect: While starch gives a blue-black color with iodine, cellulose does not give any significant color reaction with iodine under normal conditions. Starch is a polysaccharide composed of glucose units and gives a blue-black color when iodine is added, which is a characteristic test for starch. Starch occurs in plants in the form of granules, and these are particularly abundant in seeds (especially the cereal grains) and tubers, where they serve as a storage form of carbohydrates. The Cellulose, a fibrous carbohydrate found in all plants, is the structural component of plant cell walls. Cellulose is also a polymer of glucose but its structure differs from starch. Cellulose does not form the characteristic blue-black color with iodine due to the difference in the way glucose molecules are linked in cellulose. Statement (d) is correct: Both starch and cellulose are made up of glucose molecules, but in different forms. Starch consists of alpha-glucose while cellulose consists of beta-glucose.

Explanation

An aerospace and defence scientist, Kalam was involved in the development of India’s first satellite launch vehicle SLV III and was the architect of the Integrated Guided Missile Development Program. He also served as the eleventh President of India from 2002 till 2007. Dr. A.P.J. Abdul Kalam was awarded the Bharat Ratna in 1997 for his contributions to science and defense technology.

Explanation

The United Front was a coalition of political parties that was in power from 1996 to 1997. The major parties that were part of the United Front included the Samajwadi Party, the CPI (M), the Indian National Congress (which provided support), Asom Gana Parishad (AGP) and smaller regional parties. Hence among the options, Bahujan Samaj Party, Haryana Vikas Party and Samata Party were not part of United Front.

Explanation

The damage to the Spektr Module of the Russian Space Station Mir occurred due to a collision with a Soyuz cargo ship in 1997 during a routine docking maneuver. The collision caused a significant breach in the module, leading to a loss of oxygen and other technical issues.

Explanation

The venue for the preliminary talks between the Sri Lankan Government and representatives of the Tamil United Liberation Front (TULF) and other militant groups was Thimphu, the capital of Bhutan. These talks took place in 1985 and were an attempt to resolve the ongoing ethnic conflict between the Tamil population and the Sri Lankan government.

Explanation

Option (b) is correct: Indian Standard Time (I.S.T.) is based on the meridian 82°30’ E, which is the reference for I.S.T. If it is noon (12:00 PM) at I.S.T., and people at another place are having 6:00 AM morning tea, that means the time difference between the two places is 6 hours. To calculate the longitude difference:

A time difference of 1 hour corresponds to a 15° difference in longitude. Therefore, a 6-hour difference corresponds to a 90° difference in longitude (6 × 15°). Since the other place is 6 hours behind I.S.T., it must be 90° to the west of the I.S.T. meridian. I.S.T. The meridian is at 82°30’ E, so moving 90° to the west brings us to 7°30’ W. Thus, the place is at a longitude of 7°30’ W.

Explanation

A is matched with 4: Hugo de Vries proposed the Mutation Theory in the early 20th century which suggested that new species arise through sudden, discontinuous changes (mutations) in genetic material. B is matched with 3: Darwin>s Theory of Evolution was published in 1859 (On the Origin of Species). It explains evolution through natural selection and gave key concepts include adaptive radiation, survival of the fittest, and descent with modification. C is matched with 1: George Beadle and Edward Tatum proposed the One Gene One Enzyme Hypothesis, which states that each gene is responsible for producing a single enzyme that controls a specific biochemical reaction. D is matched with 2: Jacob and Monod>s Operon Concept was introduced in 1961 which explains how gene regulation in prokaryotes (e.g., lac operon in E. coli). It is key for understanding antibiotic resistance and gene expression.

Explanation

The Tambalacoque tree (Sideroxylon grandiflorum), also known as the Dodo tree, usually relied on the Dodo bird for seed germination. The seeds of this tree required scarification (softening of the seed coat) through the Dodo>s digestive system. The Dodo (Raphus cucullatus), a flightless bird endemic to Mauritius, became extinct in the late 1600s due to over-hunting by humans and the introduction of non-native animals like rats and pigs. After the extinction of the Dodo, natural reproduction of the Tambalacoque tree declined significantly.

Explanation

Aerobic respiration is the process by which glucose is completely oxidized in the presence of oxygen to produce carbon dioxide, water, and energy (in the form of ATP). The overall reaction is:

C₆H₁₂O₆ + 6O₂ 6CO₂ + 6H₂O+ Energy (ATP)

Explanation

Fish, especially oily fish like salmon, mackerel, and sardines are rich in polyunsaturated fatty acids (PUFAs) such as omega-3 fatty acids (e.g., EPA and DHA). These fatty acids are essential for various health benefits such as:

Reducing the risk of cardiovascular diseases.

Improving brain function and development.

Reducing inflammation.