UPSC Prelims Previous Year Questions 2020: Science & Technology

Ans: (d)

• Carbon nanotubes (CNTs) are cylindrical molecules consisting of a hexagonal arrangement of hybridized carbon atoms, which may be formed by rolling up sheet(s) of graphene.
• In recent years, carbon nanotubes have attracted many researchers as a drug delivery carrier. As carbon nanotubes have a high surface area, they go into the cell by the millions, and can have a very high efficiency of delivery to a specific cell. Hence, statement 1 is correct.
• Carbon nanotubes can be made into artificial blood capillaries for an injured part of the human body as they are promising drug delivery platforms that can be functionalized with a variety of biomolecules, such as antibodies, proteins, or DNA. Hence, statement 2 is correct.
• Recently, NASA has demonstrated Biochemical Sensors Using Carbon Nanotube Arrays. Hence, statement 3 is correct.
• Multiple types of microbes, including bacteria and fungi, have the ability to degrade carbon nanotubes (CNTs). Hence, statement 4 is correct.

Therefore, option (d) is the correct answer.

Ans: (d)

• Unmanned Aerial Vehicles (UAV) or drones are aircrafts that can be navigated without a human pilot on board. Drones can be navigated via control from the ground, using a GPS tracking system.
• Initially, drones have been developed mostly for military applications. However, its use has expanded to scientific, recreational, commercial and other applications including peacekeeping and surveillance, product delivery, aerial photography, agriculture, etc. They are now increasingly used to spray pesticides in agricultural fields to protect standing crops from pests. Hence, statement 1 is correct.
• Scientists have also been using drones to study active volcanoes. The drone can both collect breath samples and take high-resolution photos of the whales from the air to assess general health conditions. Hence, statements 2 and 3 are correct.

Therefore, option (d) is the correct answer.

Ans: (d)

• Evolved Laser Interferometer Space Antenna (eLISA) is a spectacular plan of setting into space three spacecrafts, a mother and two daughter spacecrafts, which will fly in a triangular formation, trailing the earth in its orbit around the sun at a distance of over.
• 50 million km. Each arm of the imaginary triangle, from the mother to each daughter spacecraft, will measure about a million km.
• eLISA seeks to measure gravitational waves in the frequency range from 0.1 mHz to about 100 mHz. To achieve this, it is necessary for the interferometers to have an arm length of a million kilometres and that is impossible to achieve with an earth based setup.

Therefore, option (d) is the correct answer.

Ans: (d)

• Germline gene therapy is the replacement of genes in egg or sperm cells with which an offspring inherits a new trait. It allows for the correction of disease- causing gene variants that are certain to be passed down from generation to generation. Hence, statement 1 is correct.
• CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) technology is employed to modify human embryos before they are transferred into women's uterus. Recently, researchers had successfully created the world's first genetically- edited baby. By using CRISPR technology, the genomes of embryos were edited to disable a gene, CCR5, which allows HIV to infect cells. Hence, statement 2 is correct.
• Due to certain anatomical and physiological features shared with humans, the pig is considered an important animal model of human diseases with unique advantages in surgery and xenotransplantation studies. Hence, statement 3 is correct.

Therefore, option (d) is the correct answer.

Ans: (b)

• Pneumococcal Conjugate Vaccines (PCVs) prevent pneumococcal diseases. Pneumococcal disease refers to any illness caused by pneumococcal bacteria. Streptococcus pneumoniae (pneumococcus) is a leading cause of bacterial pneumonia, meningitis and sepsis in children.
• PCVs could potentially prevent a substantial proportion of episodes of bacteremic disease, pneumonia, meningitis, sepsis and otitis media, especially in young children. Hence, statement 1 is correct.
• The growing resistance of pneumococcal bacteria to commonly used antibiotics underlines the urgent need for vaccines to be used to control pneumococcal disease. PCV prevents antibiotic resistant pneumococcal infections. Hence, statement 2 is correct.
• Redness, swelling, pain, or tenderness where the shot is given, and fever, loss of appetite, fussiness (irritability), feeling tired, headache and chills can happen. Hence, statement 3 is not correct.

Therefore, option (b) is the correct answer.

Ans: (a)

Public Key Infrastructure (PKI) is a technology for authenticating users and devices in the digital world. Under this system, one or more trusted parties digitally sign documents certifying that a particular cryptographic key belongs to a particular user or device. The key can then be used as an identity for the user in digital networks. Therefore, option (a) is the correct answer.

Ans: (c)

• Plant and animal cells are different as the former possess cell walls, chloroplasts, plastids and a large central vacuole which are absent in animal cells. Hence, statement 1 and 3 are correct.
• On the other hand, animal cells have centrioles which are absent in almost all plant cells. Both plant and animal cells have plasma membranes. Hence, statement 2 is not correct.

Therefore, option (c) is the correct answer.

Ans: (d)

• Pronuclear transfer involves the transfer of pronuclei from one zygote to another. This technique first requires fertilisation of healthy donated eggs (provided by the mitochondrial donor) with the intended male parent sperm. Simultaneously, the intending mother's affected oocytes are fertilised with the intending father's sperm.
• By using a technique, called 'Maternal Spindle transfer', the maternal DNA is put into the egg of a donor woman, which is then fertilized using the father's sperm.
• The procedure was developed to help existing In- vitro-Fertilization (IVF) treatments in which mothers have mitochondrial diseases.
• Mutations in maternal DNA are a cause of mitochondrial disease, a heterogeneous group of diseases that can lead to premature death, sometimes in infancy or childhood. Most mitochondrial diseases lack specific treatments, and women who carry the causative mutations are at high risk of transmitting the diseases to their offspring.

Therefore, option (d) is the correct answer.

Ans: (d)

• Google is using the Internet of Things (IoT) and Artificial Intelligence (AI) from its DeepMind acquisition to reduce energy consumption in its data centres by as much as 30%. Hence, option 1 is correct.
• Using AI as a tool to make music or aid musicians has been in practice for quite some time. In the 1990s, David Bowie helped develop the Verbasizer, which took literary source material and randomly reordered the words to create new combinations that could be used as lyrics. In 2016, Sony used software called Flow Machines to create a melody in the style of The Beatles. Music-making AI software has become advanced in the past few years. It's a viable tool that can and is being used by producers to help in the creative process. Hence, option 2 is correct.
• AI combined with robotics and the Internet of Medical Things (IoMT) could potentially be the new nervous system for healthcare, presenting solutions to address healthcare problems. Integration of AI technology in cancer care could improve the accuracy and speed of diagnosis, aid clinical decision-making, and lead to better health outcomes. Hence, option 3 is correct.
• Speech synthesis is the artificial production of human speech. It is a way to convert language to human voice (or speech). For example, Google's Assistant, Amazon's Echo, Apple's Siri, etc. Hence, option 4 is correct.
• Potential cases of Al's use in the energy sector include energy system modelling and forecasting to decrease unpredictability and increase efficiency in power balancing and usage. Wireless transmission of electrical energy is not a new technology. In a wireless power transmission system, a transmitter device, driven by electric power from a power source, generates a time-varying electromagnetic field, which transmits power across space to a receiver device, which extracts power from the field and supplies it to an electrical load. Hence, option 5 is correct.

Therefore, option (d) is the correct answer.

Ans: (c)

• Visible Light Communication (VLC) systems employ visible light for communication that occupy the electromagnetic spectrum from 375 nm to 780 nm. Hence, statement 1 is correct.
• VLC is known as short-range optical wireless communication. Hence, statement 2 is not correct.
• Li-Fi, a kind of VLC, has a range of approximately 10 meters and it cannot pass through walls or any solid object.
• VLC can transmit large amounts of data faster than bluetooth. The VLC uses visible light for communication to provide high speed internet up to 10 Gb/s while Bluetooth 4.0 promises speeds up to 25 Mb/s. Hence, statement 3 is correct.
• VLC has no electromagnetic interference. The radio frequency (RF) based signals have the problem of interference with other RF signals such as its interference with pilot navigational equipment signals in aircraft. Therefore, in the areas that are sensitive to electromagnetic radiation (such as aircrafts) VLC can be a better solution. Hence, statement 4 is correct.

Therefore, option (c) is the correct answer.

Ans: (d)

• A blockchain is a form of public ledger, which is a series (or chain) of blocks on which transaction details are recorded and stored on a public database after suitable authentication and verification by the designated network participants. A public ledger can be viewed but cannot be controlled by any single user. Hence, statement 1 is correct.
• The blockchain is not only about the cryptocurrency but it turns out that blockchain is actually a pretty reliable way of storing data about other types of transactions, as well. In fact, blockchain technology can be used in property exchanges, bank transactions, healthcare, smart contracts, supply chain, and even in voting for a candidate. Hence, statement 2 is not correct.
• Although cryptocurrency is regulated and needs approval of the central authorities, blockchain technology is not only about cryptocurrency. It can have various uses, and applications based on basic features of the technology can be developed without anybody' approval. Hence, statement 3 is correct.

Therefore, option (d) is the correct answer.

Ans: (d)

• The main components in a solar pumping system include a photovoltaic (PV) array, an electric motor and a pump.
• There are several different types of solar-powered pumps depending on their functional
• mechanism. But primarily there are four types of solar water pumps - submersible pumps, surface pumps, direct current (DC) pumps and alternate current (AC) pumps. Hence, statement 1 is not correct.
• Solar Power can be used to run both centrifugal as well as piston pumps. Hence, statement 2 is not correct.

Therefore, option (d) is the correct answer.

Ans: (b)

• The nuclear facilities are kept under International Atomic Energy Agency (IAEA) safeguards if the source of Uranium which is the fissile material for a nuclear reactor is from outside the territory of India or if the new reactor plants are established with foreign collaboration.
• This is to ensure that imported uranium was not diverted for military use and assure that the imported uranium is used to generate nuclear energy for civilian purposes. There are at present 22 operational reactors, of which 14 are under the International Atomic Energy Agency (IAEA) safeguards as these use imported fuel.
• Under safeguards agreement, the International Atomic Energy Agency (IAEA) has the right and obligation to ensure that safeguards are applied on all nuclear material in the territory, jurisdiction or control of the State for the exclusive purpose.

Therefore, option (b) is the correct answer.