UPSC 1998 Science and Technology Questions with Answers

Explanation

In industrial applications, a wide range of microorganisms are used due to their ability to carry out various biochemical processes that are beneficial for different industries. The following microorganisms are widely used:

Bacteria is used in industries such as fermentation, bioremediation, and food production (e.g., yogurt, cheese, and antibiotics). Microalgae is used in the production of biofuels, aquaculture feed, and nutraceuticals. They are also involved in carbon sequestration. Fungi is widely used in the pharmaceutical industry for the production of antibiotics (such as penicillin) and enzymes. They are also used in fermentation and the production of organic acids.

Explanation

A is matched with 4: Fruit develops from the ovary of the flower after fertilization. The ovary, which contains the ovules, transforms into the fruit as the seeds inside mature. This process is an essential part of the plant’s reproductive cycle. B is matched with 1: Seed originates from the ovule after fertilization. The ovule, located inside the ovary, contains the female gamete (egg cell). Once fertilized by the male gamete (pollen), the ovule develops into a seed, which contains the embryo and stored food for the new plant. C is matched with 3: Wood is produced from the stem of the plant. The stem, with its vascular tissues (xylem and phloem), supports the plant and transports nutrients. The xylem, which is a type of vascular tissue, forms the wood, providing structural support and helping in water transport. D is matched with 2: Starch is primarily produced in the leaf. During photosynthesis leaves use sunlight, water, and carbon dioxide to produce glucose. Some of this glucose is converted into starch, a storage form of sugar, and is stored in the chloroplasts of the leaf.

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

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.

Explanation

A is matched with 4: Malaria is Caused by protozoan parasites of the genus Plasmodium (e.g., Plasmodium falciparum, Plasmodium vivax), transmitted through the bite of infected female Anopheles mosquitoes. India’s National Malaria Elimination Programme (NMEP) aims to eliminate malaria by 2030 under the National Center for Vector Borne Diseases Control (NCVBDC). WHO has approved RTS, S/AS01 (Mosquirix) vaccine for children. B is matched with 3: Polio is caused by the poliovirus (genus Enterovirus) which spreads via contaminated food, water, or contact. Widely available vaccines (OPV and IPV) prevent polio. India’s Pulse Polio Programme launched in 1995 achieved polio-free certification in 2014. C is matched with 2: Tuberculosis is caused by Mycobacterium tuberculosis. It primarily affects the lungs and spreads through the air. The BCG vaccine provides TB prevention in children. India’s National Tuberculosis Elimination Programme (NTEP) offers free treatment and nutrition support under Nikshay Poshan Yojana, aiming for elimination by 2025. D is matched with 1: Ringworm is a fungal infection caused by dermatophytes such as Trichophyton, Microsporum, or Epidermophyton. It affects the skin, hair, or nails, spreading through direct skin contact or contaminated surfaces.

Explanation

Haemophilia is a genetic disorder where the blood does not clot properly due to a deficiency of clotting factors (such as Factor VIII in Haemophilia A or Factor IX in Haemophilia B). This leads to excessive bleeding even from minor injuries.