UPSC 2014 Science and Technology Questions with Answers

Explanation

Pair 1 is correctly matched: Scurvy is caused by a deficiency of Vitamin C (ascorbic acid). It leads to symptoms like bleeding gums, bruising, fatigue, and poor wound healing.

Pair 2 is correctly matched: Rickets occurs due to Vitamin D deficiency, which impairs calcium absorption, leading to soft and weak bones in children. In adults, it can lead to osteomalacia.

Pair 3 is incorrectly matched: Night blindness is caused by a deficiency of Vitamin A, not Vitamin E. Vitamin A is crucial for maintaining healthy vision, particularly in low-light conditions. Vitamin E deficiency, on the other hand, may lead to nerve and muscle damage or immune system issues.

Explanation

Diphtheria has not been eradicated in India. It remains a public health concern, with cases still reported annually. It is a bacterial disease caused by Corynebacterium diphtheriae. It primarily affects the respiratory system, causing symptoms such as a sore throat, fever, and difficulty breathing. A characteristic thick gray membrane forms on the throat and tonsils in severe cases. Diphtheria spreads through respiratory droplets or contact with contaminated objects. It is preventable through the DPT (Diphtheria-Pertussis-Tetanus) vaccine, which is part of India’s Universal Immunization Programme (UIP). Chickenpox has not been eradicated in India. It is a common infectious disease, particularly among children, and continues to occur throughout the country. It is caused by the Varicella-zoster virus (VZV), a highly contagious virus that spreads through respiratory droplets or direct contact with blisters. Symptoms include an itchy rash with red spots or blisters, fever, and fatigue. Following extensive surveillance and immunization campaigns, the World Health Organization (WHO) declared India free of smallpox in 1977. It is caused by the Variola virus, was one of the deadliest diseases in history, with a high mortality rate of 30%. It presented with symptoms like high fever, severe headache, and distinctive pus-filled blisters. Smallpox spread through direct contact with infected individuals or contaminated objects.

Explanation

Biometrics identification is a form of identification and access control. Biometric identifiers are the distinct, measurable characteristics used to label individuals. Physiological characteristics are distinguished from behavioural traits when classifying biometric identifiers. Fingerprint, palm veins, face recognition, DNA, palm print, hand geometry, iris recognition, retina, and odour/scent are examples of physiological biometric identifiers. Visible and near - infrared light used captures and analyzes the unique patterns in the colored part of the eye surrounding the pupil. It is a highly reliable and accurate biometric method used in security and access control systems. It is used in Aadhaar biometric identification in India. Retinal scanning maps the unique pattern of blood vessels in the retina at the back of the eye. This method is highly accurate but less commonly used due to its intrusive nature, requiring the user to position their eye close to the scanner. Voice recognition analyzes the unique characteristics of an individual’s voice, such as tone, pitch, and rhythm, for authentication. It is widely used in phone-based security systems and other applications requiring remote verification.

Explanation

Pair 1 is incorrectly matched: The Cassini-Huygens mission was a collaborative project between NASA, the European Space Agency (ESA), and the Italian Space Agency (ASI) to study Saturn and its moons, not Venus. Huygens probe landed on Titan, Saturn’s largest moon in 2005 and provided valuable data about its atmosphere and surface.

Pair 2 is correctly matched: The Messenger (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft was a NASA mission designed to study Mercury. It orbited Mercury and mapped its surface, studying its geology, and investigating its magnetic field and exosphere.

Pair 3 is correctly matched: The Voyager 1 and Voyager 2 spacecraft were launched by NASA in 1977 to explore the outer planets of the solar system. Voyager 1 flew by Jupiter and Saturn, providing detailed images and data about these planets and their moons. Voyager 2 visited all four outer planets:

Jupiter, Saturn, Uranus, and Neptune. The spacecraft are now in interstellar space, continuing to transmit data about the heliosphere and beyond.

Explanation

Option (b) is correct: Cluster bean commonly known as guar has traditionally been utilized in India as a vegetable and animal feed. Guar gum is widely used in the oil and gas industry particularly in hydraulic fracturing (fracking) for shale gas extraction. It acts as a thickening agent in fracking fluids, helping to carry proppants (like sand) into fractures in the shale rock to keep them open and allow gas to flow. India is one of the largest producers of guar in the world and the demand for guar gum surged due to its use in shale gas extraction especially in the United States.

Option (a),(c) and (d) are incorrect:

Guar seeds are primarily known for their gum content and not oil. It has applications in various industries (food, pharmaceuticals, textiles, etc.) but there is no widespread use of guar seed oil in the manufacture of biodegradable plastics. Traditionally guar leaves have been consumed as a vegetable but their medicinal properties particularly as antihistamines is not well-documented. Guar seeds are not a significant source of biodiesel. It is not commercially significant or widely recognized as a high-quality biodiesel source.

Explanation

The Agni-IV is an intermediate-range ballistic missile developed by India’s Defence Research and Development Organisation (DRDO)

Statement 1 is correct: The Agni-IV is designed as a surface-to-surface missile, capable of being launched from the ground to strike terrestrial targets. It enhances India’s strategic strike capabilities. Statements 2 is incorrect: The Agni-IV utilizes a two-stage solid propellant system, not liquid propellant. Solid propellants offer advantages such as easier handling and longer storage life, which are beneficial for ballistic missiles. Statements 3 is incorrect: The Agni-IV has a range of around 4,000 km and is capable of carrying a payload of up to one tonne, including nuclear warheads. A range of 7,500 km would classify the missile as an intercontinental ballistic missile (ICBM), but the Agni-IV is categorized as an intermediate-range ballistic missile (IRBM).

Explanation

Photosynthesis is the process by which green plants, algae, and certain bacteria convert light energy into chemical energy, producing glucose and releasing oxygen. The functions of the chlorophyll, a green pigment, are related to the transformation of inefficient solar energy into useful chemical energy. During photosynthesis, plants capture light energy (free energy) and convert it into chemical energy, storing it as potential energy in the bonds of glucose molecules. This stored energy can later be used by the plant for various metabolic processes. 6H₂O + 6CO₂C₆H₁₂O₆ + 6O₂

Explanation

Vegetative propagation is a fascinating form of asexual reproduction where new plants grow from specialized vegetative parts like stems, roots, or leaves rather than seeds.

Statement 1 is correct: Vegetative propagation is a process in which new plants are grown from the vegetative parts of the parent plant. As this method does not involve sexual reproduction, the offspring are genetically identical to the parent, creating a clonal population. This technique ensures uniformity among the progeny, making it particularly useful for preserving desirable traits in cultivated plants.

Statement 2 is incorrect: Standard methods of vegetative propagation generally do not eliminate viruses rather they often perpetuate viral infections because the new plants are exact genetic clones of the infected parent plant.

Statement 3 is correct: Unlike seed-based propagation, which is often dependent on specific seasons, methods like cuttings, layering, or tissue culture can be carried out continuously as long as the required conditions and resources are provided. Vegetative propagation can typically be practiced year-round, particularly in controlled environmental settings. This adaptability enables the consistent production of new plants.

Explanation

Transgenic crops are developed by introducing foreign genes into a plant’s genome to confer new traits, such as pest resistance or improved nutritional content.

Statement 1 is incorrect: Budding and grafting are traditional horticultural techniques used to propagate plants. In grafting, tissues from one plant are inserted into those of another so that the two sets of vascular tissues may join together. These methods do not alter the genetic makeup of the plants.

Statement 2 is correct: Cytoplasmic male sterility (CMS) refers to the complete or partial inability of plants to produce functional male gametes. Male Sterility prevents the plant from producing viable pollen, thereby rendering it incapable of self-fertilization. CMS systems are extensively used in hybrid crop production because they simplify the process of controlling male sterility, eliminating the need for manual emasculation during cross-breeding. This enhances efficiency and consistency in hybrid seed production.

Statement 3 is correct: Gene silencing refers to techniques used to suppress the expression of specific genes within an organism. In the context of transgenic crops, methods such as RNA interference (RNAi) are employed to downregulate or silence target genes, thereby conferring desired traits like pest resistance or delayed fruit ripening. One notable example of gene silencing in India is the development of Bt Cotton using RNA interference (RNAi). In Bt cotton, a gene from the soil bacterium Bacillus thuringiensis (Bt) is introduced to produce proteins that are toxic to cotton bollworm pest.

Explanation

Statement 1 is correct: Maize is a primary source for commercial starch production. Through a wet milling process, maize kernels are separated into components such as starch, oil, protein, and fiber. The extracted starch is utilized in multiple industries, including food, paper, and textiles.

Statement 2 is correct: Maize oil, also known as corn oil, can be used as a raw material for biodiesel production. Through a chemical process called transesterification, the oil reacts with short-chain alcohols such as methanol or ethanol, using a catalyst to produce biodiesel efficiently.

Statement 3 is correct: Maize plays a significant role in the production of various alcoholic beverages. Its starch is broken down into sugars, which are subsequently fermented to produce alcohol. This process is crucial in crafting drinks like bourbon whiskey, which traditionally uses a mash containing at least 51% maize.