UPSC 2022 Science and Technology Questions with Answers

Explanation

Probiotics are live microorganisms that are intended to have health benefits when consumed or applied to the body.

Statement 1 is correct: Probiotics can be composed of bacteria, yeast, or both. The most common types of bacteria used as probiotics are Lactobacillus and Bifidobacterium, while Saccharomyces boulardii is an example of a yeast that is sometimes used as a probiotic.

Statement 2 is incorrect: Probiotics contain microorganisms that are similar to or the same as those naturally present in our bodies, especially in the digestive tract. Our gut microbiota consists of many types of bacteria, some of which are also found in probiotic products. These probiotics are often called "good" or "friendly" bacteria because they support gut health.

Statement 3 is correct: Some probiotic bacteria, like Lactobacillus, produce an enzyme called lactase, which helps in the digestion of milk sugar (lactose). Lactase breaks down lactose into simpler sugars, making it easier for the body to absorb. This is especially helpful for people who are lactose intolerant and have difficulty digesting dairy products.

Explanation

B cells and T cells are integral components of the human immune system, each playing distinct roles in protecting the body from diseases caused by pathogens. B cells are primarily responsible for humoral immunity. They produce antibodies that specifically target and neutralize pathogens such as bacteria and viruses. T cells play a crucial role in cell-mediated immunity, not by producing antibodies but by carrying out essential immune functions. Helper T cells activate B cells to stimulate other immune cells to enhance the body’s defense. Cytotoxic T cells target and destroy infected or cancerous cells, eliminating harmful threats. Regulatory T cells help maintain immune balance by preventing excessive or inappropriate immune responses.

Explanation

Software as a Service (SaaS) refers to software provided by a third party as a service where hosting and maintenance are managed by the provider. Unlike traditional methods requiring local deployment and maintenance SaaS allows direct access to software via thin clients such as web browsers.

Statement 1 is correct: SaaS applications often provide customization options, allowing users to adjust the user interface (UI) and modify data fields according to their business requirements. However, customization is typically limited to certain areas defined by the service provider and may not involve deep structural changes.

Statement 2 is correct: SaaS platforms are accessible via the internet and can be used across devices, including desktops, laptops, and mobile devices. This accessibility is a key feature of SaaS, as users can access their applications and data on the go through web browsers or mobile apps.

Statement 3 is correct: Email services such as Outlook, Hotmail, and Yahoo Mail are classic examples of SaaS. They deliver email functionality over the internet without requiring users to install software locally. These services are hosted by the provider and accessed through browsers or apps.

Explanation

Statement 1 is correct: A fundamental principle of Web 3.0 is to grant users ownership and control over their personal data, reducing reliance on centralized entities. This shift aims to enhance privacy and security for individuals.

Statement 2 is correct: Web 3.0 leverages blockchain technology to create decentralized applications, including social networks. These platforms operate without central authorities, offering users greater control over content and data.

Statement 3 is correct: Decentralization is a hallmark of Web 3.0, where control is distributed among users instead of being held by centralized corporations. This collective operation is facilitated through decentralized networks and consensus mechanisms.

Explanation

Quantum computers are machines that use the properties of quantum physics to store data and perform computations. A classical computer performs operations using classical bits, which can be either 0 or 1. Quantum computer uses quantum bits or Qubits, which can be both 0 and 1 at the same time. Qubits (or quantum bits) are the units of computation in quantum computers. They take advantage of quantum mechanics characteristics, which regulate how matter behaves at the atomic level. Quantum computers are faster, more accurate, & energy efficient. Two important phenomena of quantum physics that are used to achieve functioning of quantum computing are:

1. Superimposition: Each quantum bit (basic unit of information in a quantum computer) can represent both a 1 and a 0 at the same time, which is known as superposition.

2. Quantum Entanglement: Subatomic particles become "entangled" (connected) in quantum entanglement, which means that any change in one upsets the other, even though they are at opposite ends of the universe.

Explanation

Short-Range Devices (SRDs) are communication technologies designed for limited-distance operations, typically within a few meters to a few hundred meters.

Option 1 is correct: CCTV systems use video cameras to transmit signals to specific monitors for surveillance purposes. The transmission range of CCTV systems is generally confined to the premises being monitored, making them short-range by design.

Option 2 is correct: RFID employs electromagnetic fields to automatically identify and track tags attached to objects. They are typically short-range, with passive RFID tags readable from up to a few meters and active tags extending up to 100 meters.

Option 3 is correct: WLANs enable wireless network communication within a localized area, such as a home or office, using high-frequency radio waves. The effective range of WLANs is usually within 100 meters, categorizing them as short-range communication technologies.

Explanation

A solar storm is a disturbance on the Sun that can release a burst of energy and particles into space. These eruptions, such as solar flares and coronal mass ejections, can impact Earth by disrupting communication systems, damaging satellites, and even causing power outages. Statements 1 and 7 are correct: These solar explosions propel bursts of particles and electromagnetic fluctuations into Earth’s atmosphere that could lead to the malfunction of satellites, which might impact high-frequency communication blackouts, satellite anomalies, GPS scintillations, airline communication.

Statement 2 is incorrect: Solar storms affect the Earth’s magnetosphere and ionosphere but do not directly cause tsunamis, which are triggered by seismic activity, underwater landslides, or volcanic eruptions.

Statement 3 is correct: The solar explosions propel bursts of particles and electromagnetic fluctuations into Earth’s atmosphere that could destroy transformers in power systems.

Statement 4 is correct: Energy, radiation and high energy particles emitted by solar flares can trigger intense lights in the sky, called Auroras.

Statement 5 is incorrect: Flares are electromagnetic radiation bursts rather than actual fires. They won’t start forest fires as a result. While they release high-energy radiation, it does not directly ignite fires on Earth.

Statement 6 is correct: Particles from a CME can potentially collide with a satellite’s critical electronics, causing the satellite’s systems to malfunction.

Explanation

The Fractional Orbital Bombardment System (FOBS) is a missile technology designed to place a nuclear warhead into a partial Earth orbit before deorbiting to strike a target. Unlike intercontinental ballistic missiles (ICBMs), FOBS takes an unpredictable orbital path, bypassing traditional radar systems and potentially striking from unexpected directions, such as via the South Pole. Originally developed by the Soviet Union in the 1960s, FOBS was tested with the R-36ORB missile but later abandoned under arms control treaties like SALT II and the Outer Space Treaty. Recent reports indicate renewed interest, with countries like China reportedly testing FOBS integrated with hypersonic glide vehicles. Its capability to evade missile defenses has raised global security concerns and spurred advancements in countermeasures. ICBM Radar Beam Launch site FOBS FOBS Apogee ~150 km ~1200 km Target Early-warning Radar Fig: Fractional Orbital Bombardment System (FOBS)

Explanation

A biofilm is a collection of microbial cells that are encased in a polysaccharide-based matrix and are permanently attached to a surface (i.e., cannot be removed by gentle rinsing). Microorganisms that form biofilms include bacteria, fungi, and protists. Noncellular materials such as mineral crystals, corrosion particles, clay or silt particles, or blood components, depending on the environment in which the biofilm has developed, may also be found in the biofilm matrix.

Statement 1 is correct: Biofilms may form on a wide variety of surfaces, including living tissues, food and food processing surfaces, indwelling medical devices (devices in the body like catheters, heart valves), human and animal tissue, industrial or potable water system piping, or natural aquatic systems.

Statement 2 is correct: Biofilms are a significant concern in the food industry, forming on surfaces such as cutting boards, conveyor belts, and food packaging equipment. Contaminated biofilms can lead to foodborne illnesses caused by pathogens like Listeria monocytogenes, Salmonella, and Escherichia coli.

Statement 3 is correct: Microorganisms in biofilms are significantly more resistant to antibiotics compared to planktonic (free-floating) cells because:

The EPS (extracellular polymeric substance) matrix acts as a barrier, limiting antibiotic penetration. Cells within biofilms have reduced metabolic activity, making them less susceptible to antibiotics targeting active processes. Some bacteria within biofilms can exchange antibiotic resistance genes via horizontal gene transfer. This resistance complicates treatment, especially in chronic infections such as cystic fibrosis, where Pseudomonas aeruginosa biofilms are common.

Explanation

Some species of ants such as leafcutter ants (of genus Atta and Acromyrmex) are well-known for cultivating fungi. These ants cut leaves and use them to grow fungi in specialized underground gardens. The fungi serve as the primary food source for the ant colony. This relationship between ants and fungi is a classic example of mutualism where both species benefit. The ants provide the fungi with a controlled environment and a constant supply of plant material while the fungi provide the ants with a nutritious food source. Leafcutter ants are primarily found in Central and South America,