 Hello everyone, welcome to Shankar's summary for Science and Technology part 2. In this video, we are going to cover 15 most important science and technology topics with MCQs. And we are going to cover it from June 2023 to February 2024. So watch this video fully and post your answers in the comment section. Now we shall move on to the first topic. So in this question, they are asking about zero trust authentication. So let us learn about this concept and come back to this question. So what is zero trust authentication? Zero trust authentication, ZTA is a security concept and framework that operates on the principle of never trust always verify. This is a cyber security approach, which is a significant shift from traditional security models that operated under the assumption that everyone inside an organization's network should be trusted. In contrast, zero trust assumes that trust is never granted implicitly, but must be continuously evaluated and authenticated, regardless of the user's location or the network's perimeter. I'll give you an example to understand this concept. Imagine your home is like a computer network. In the old days, security was like having a strong fence and a locked front door. Once you were inside the house, that is the network, it was assumed you were supposed to be there and you could go anywhere you liked, like the kitchen, living room, everywhere. This is how the traditional computer networks work. If you were inside the system trusts you, but there is a problem with this approach. What if someone who isn't supposed to be there gets in? This is a big risk in computer networks too. Once inside, a hacker could do a lot of damage. Zero trust authentication, that is ZTA changes the game. It's like having a guard inside your house who checks your ID card every time you want to enter into a new room, even if you are just going from kitchen to living room. It doesn't matter that you are already inside the house. You need to prove you're allowed to be there every single time you move. So that is all about zero trust authentication. So in the context of zero trust authentication, consider the following statements. First statement, it shifts from the traditional security model by assuming potential threats can exist both inside and outside of an organization's network. Yes, this statement is correct. Next, under zero trust authentication, once a user or device is authenticated and granted access, no further verification is required for subsequent action within the network. This statement is incorrect. They're asking which of the statements are incorrect. So the answer is option B only two. So with this, let us move to the next topic. So in this question, they're asking about deep fakes. So deep fakes have been in use for many times recently. So let us learn a few things and come back to this question. So what is deep fakes? See deep fakes are like digital puppetry, but instead of using strings to control the puppet, they use advanced computer programs. These programs can take videos, images or sounds of real people and can change them into look like those people are saying or doing things they never actually did. The secret ingredient behind deep fake is a type of artificial intelligence known as deep learning, which helps explaining the deep and deep fake. So creating a deep fake involves a special team of between two AI systems called Generative Adversarial Network, GAN. One part of the GAN, the generator is like an artist that creates fake images or videos. The other part, the discriminator acts like a critic trying to part which creations are fake. They keep going back and forth with the artist trying to outsmart the critic by making more and more convincing fakes and the critic getting better at spotting them. This process keeps going until the fakes are so good they are almost indistinguishable from the real videos or images. So this is how deep fakes are made. So in this question, first statement, deep fakes are fake videos or audios that look and sound real. Yes, this statement is correct. Next, these are created using artificial intelligence specifically through a technique called Generative Adversarial Networks. Yes, this statement is also correct and it explains the statement one. So the answer is option A, both one and two are correct and statement two is the correct explanation of statement one. So with this, let us move to the next topic. So in this question, they are asking about Matsya 6000. So India's deep ocean mission was in use for many times. So let us learn about the deep ocean mission and come back to this question. So what is the deep ocean mission? Deep ocean mission is India's ambitious mission to explore and harness the depths of ocean that is approximately 6000 meters. The Ministry of Ed Science will be the nodal ministry for implementing this particular mission. Know that the estimated cost of this mission is 4,077 crores and the mission is for the period of five years that is 2021 to 2026. Moreover, this mission is one of the nine missions under the Prime Minister's Science, Technology and Innovation Advisory Council PM STIAC. Now let us see about the important component of this mission that is Matsya 6000. Matsya 6000 is also known as Samudrayan Mission. It is a part of deep ocean mission and in fact the first component of the mission. Moreover, this is India's first manned mission to explore the deep of the oceans. It aims to send three personnel to 6000 meter depth in a vehicle called Matsya 6000. The purpose of this mission is to explore the deep sea resources like polymetallic nodals, etc. Know that Matsya 6000 vehicle is designed and developed by National Institute of Ocean Technology, NEOT, which is located in Chennai under the Ministry of Earth Science. Let us see the details about Matsya 6000. Look at this picture. Matsya 6000 has a spherical titanium hull made up of titanium alloy. This was developed by Vikram Sara by Space ISRO. Know that it is equipped with life support system, support for floating underwater and provisions for collecting underwater samples. It has a 6000 meter deep rated remotely operated vehicle. The vehicle has an endurance time of 12 hours under the normal operation and 96 hours in case of emergency for human safety. So this is all about the deep ocean mission. Which of the following statements is correctly describes Matsya 6000. First, it is a space mission by India to explore underwater galaxies. Know it is wrong. It is an initiative to digitally map agricultural lines. Know it is not correct. It is a deep sea exploration project aimed at studying ocean biodiversity. Yes, this statement is correct. It is a government scheme to provide financial assistance to 6000 farmers. This statement is also incorrect. So the answer is option C, deep sea exploration project. So with this, let us move to the next topic. So in this question, they are asking about autoimmune disease. So UPSC is frequently asking about immune system. For example, see this question. In 2022, they asked about B cells and T cells. So let us learn about autoimmune disease and come back to these questions. So what is autoimmune disease? See, generally the body's immune system protects us against illness and infection. However, when the immune system is damaged, it wrongly targets healthy cells, tissues and organs for assault. These types of diseases are called as autoimmune diseases. So there are more than 80 autoimmune diseases in the world. Some are well known such as type 1 diabetes, multiple sclerosis, lupus and primotoid arthritis, etc. Research show that about 10% of people have autoimmune disease with women being more affected compared to men. Even recently, Bollywood heroine was also died of dermatomyositis, which is an autoimmune disease. So why are women more affected? Scientists have been trying for a long time to figure this out. A recent discovery suggests that a molecular coating on the X chromosome could be a key factor in the higher rate of autoimmune diseases in the women. See, this disease involves a process called X chromosome inactivation. Here, out of two set of chromosomes in a female body, one set is inactivated. This is done by a long strand of RNA, which is also called as ZIST. It is found in the molecular coating on X chromosome. The ZIST attracts proteins and silences the expression of the gene inside. Since it is expressed only in the cells with two X chromosomes, women are more susceptible to autoimmune diseases and attacks. However, not all genes on the X chromosomes get silenced. Those that remain active might trigger autoimmune disease. Note that majority of the autoimmune diseases are chronic and there is no definite cure. So in conclusion, we can say that the presence of two X chromosomes and the behavior of ZIST RNA in women make them more prone to autoimmune diseases. So which of the following statements is true about autoimmune diseases? As we know, the answer is option A. Autoimmune diseases occur when the immune system mistakenly attacks the body's own tissues, recognizing them as foreign. So in this previous request, they are asking about the role of B cell and T cell. Here the answer is option D. They protect the body from the disease caused by pathogens. So with this, let us move to the next topic. Look at this question. Here they are asking about zero-click exploit and about Pegasus. So let us learn a few things about this and come back to this question. So let us understand zero-click exploit. First we know that Pegasus software is like a sneaky computer virus created by a company in Israel called NSO Group. Imagine someone could secretly pick into your smartphone, reading your messages, listening to your calls and even watching through your camera without you doing anything to let them in. That's what Pegasus can do. It uses special tricks called zero-click exploit to sneak into any smartphones without needing the owner to click on bad link or download a harmful app. Once it is in, Pegasus has the key to everything on the phone. It can see text, hear calls, access emails and even turn on the camera and microphone to spy in real time. A zero-click exploit is like a magic trick for hackers. Normally to install bad software on your phone or computer, they would trick you into clicking on something you shouldn't like a fake email link. But with the zero-click exploit, they don't need you to do anything at all. You could just be sitting there and if your device is targeted, this exploit can install spyware without your knowledge or action from you. It's a scary thought because it means that just about any device can be attacked without warning. So in the context of zero-click exploit, consider the following statements. A zero-click exploit refers to malicious software and it does not require the device owner to perform any actions to initiate or complete the installation. Yes, this statement is correct. Next, Pegasus is a malware or spyware developed to access any smartphone through zero-click exploit remotely. Yes, this statement is also correct. They're asking which are all the statements are correct. So answer is option C, both one and two. So with this, let us move to the next topic. Look at this question. Here they're asking about nicotine. We know that e-cigarette was in use. So let us learn few things about e-cigarette and come back to this question. So what are e-cigarettes? E-cigarettes or electronic cigarettes is a gadget that mimics smoking tobacco. The components of e-cigarette includes your mouthpiece, a cartridge, a heating element or automizer, a microprocessor, a battery and some of them have LED light on the end. Let's briefly look at the functions of these components. See, once the e-cigarette is on, the power source from the battery is converted into heat energy. This heat energy is fed into the heating component or the automizer. The automizer evaporates the liquid solution inside the cartridge into a fine mist of vapor and air that soon cools. This creates smoke which is inhaled using a mouthpiece. In between, there is an air flow sensor that detects when you suck in the air from the mouthpiece. Once the air is sucked into the device, the sensor alerts the microprocessor to start the heating element that turns the liquid solution into vapor. This is how e-cigarette works. Remember, there are many different types of e-cigarettes in use. It includes electronic nicotine delivery system, ENDS and electronic non-nicotine delivery system, ENNDS. See, the difference here is that if the solution in the cartridge is filled with nicotine, it is known as ENDS. And if it is filled with nicotine-flavored additives, then it is known as ENNDS. Here, you should know about the nicotine. Nicotine is an alkaloid that is found in certain plants like nicotine or tobacco plant that is used to produce tobacco products. Within the tobacco plant, nicotine is synthesized in the roots and accumulates in the leaves. In tobacco, nicotine makes up between 0.6 and 3% of the total dry weightage, which is about 1.2 to 1.4 mg per milliliter. But the same nicotine is used as a direct substance in e-cigarettes and the content ranges up to 36 mg per milliliter. One of the issues with nicotine is that it reaches the brain within seconds of taking a puff. In the brain, nicotine increases the release of brain chemicals called neurotransmitters, which help regulate mood and behavior. Dobermine, one of these neurotransmitters, is released in the river-center of the brain and causes feeling of pleasure and improved mood. So, the more you smoke, the more nicotine you need to feel good. It quickly becomes a part of your daily routine and interwind with your habits and feelings. Nicotine can also cause an increase in blood pressure, heart rate, flow of blood to heart and a narrowing of the arteries. It may also contribute to hardening of the arterial walls, which in turn may lead to heart attack. So, what is the primary effect of nicotine on the human body? Here, the answer is C. It stimulates the central nerve system leading to increased alternates and heart rate. So, with this, let us move to the next topic. Next question. So, here they are asking about lumpy skin disease. We know that lumpy skin disease affected many cattle population in Northern India. So, let us learn about this disease and come back to this question. So, what is lumpy skin disease? Lumpy skin disease is a highly infectious viral disease that affects cattle and poses a threat to income and full security of the country. It is caused by the lumpy skin disease virus LSDV, which belongs to the genus of capripox virus and a part of poxviride family. Know that smallpox and monkey poxviruses are also part of this poxviride family. Actually, you might have seen this earlier. It looks like a large pimples on the face and body. An important point to be noted is LSDV is not a genomic virus, meaning that disease cannot spread from animal to humans. So, let us see how it spreads. See, LSDV spreads through blood-sucking vectors like ticks, mites, house flies, mosquitoes, etc. It also spreads through contaminated water, fodder and feed. In some cases, LSDV directly spreads from animal to animal. Now, let us see the symptoms of LSDV. First of all, LSDV affects the lymph nodes of an infected animal. It will cause the nodes to enlarge and appear like lumps on the skin. It is because of this, it is called as lumpy skin disease. The other symptoms are high fever, sharp drop in milk yield, discharge from the eyes or nose, salivation, loss of appetite, depression, damaged hides, emaciation, that is, thinness or weakness of animals, infertility and abortions. The LSDV can even lead to death of a cattle. Finally, let us see the treatment process. See, LSDV has no direct antiviral treatment, so the infected animals will receive supportive care. This means the use of antibiotics, painkillers and wound care sprays to treat the symptoms. As it has no treatment, it is better to use vaccines and prevent the transmission of the disease. In understanding this, the LSDV is covered under the Livestock Health and Disease Control Program of India. Moreover, in January 2023, a live attornated vaccine for LSD called Lumpy Provac Ind is jointly developed by Indian Council for Agriculture Research National Research Centre on Equines and the Indian Vatinity Research Institute. Note that it will provide 100% protection against this disease. So, this is all about the lumpy skin disease. So, coming back to the question, in the context of lumpy skin disease, consider the following statements. It is caused by virus that belong to genus Capripox virus, which is a part of poxviridae family. Yes, this statement is correct. It can spread from animal to humans, classifying it as a zoonotic virus. This statement is incorrect because it spreads from animals to animals, not animals to humans. So, it is not zoonotic virus. Next, a live attornated vaccine called Lumpy Provac Ind has been developed to provide 100% protection against lumpy skin disease. Yes, this statement is correct. Next, LSD is primarily transmitted through direct contact between animals. This statement is incorrect because it is primarily transmitted through the fluid. So, the answer is option D1 and 3. So, with this, let us move to the next topic. So, in this question, they are asking about ketamine. So, let us learn about ketamine and come back to this question. So, what is ketamine? Ketamine is a dissociative anesthetic halosinogen that has been used as an anesthetic for animals since 1960s. Later, it was approved for human use by US Food and Drug Administration. Ketamine is known for creating a feeling of detachment from pain and the environment. In recent years, ketamine has gained attention for its potential therapeutic effects in treating depression and other serious mental health issues. Especially, in case where traditional therapies have not been effective. So, talking about the method of consumption, the patients with mental health issues typically take ketamine through an intravenous line i.e., IV. Then, nasal spray or tablet once or twice a week for a specified treatment period. For recreational purposes, the ketamine is often snored as a white crystalline powder. It can also be injected or smoked. So, talking about the effects of ketamine, some patients undergoing ketamine treatment report positive experiences describing it as a reset button for their brain. During treatment sessions, individuals may have pleasant visualizations and sense of detachment leading to reduction in the perceived weight of daily problems. Ketamine affects brain receptors that traditional antidepressants do not target, leading to a psychedelic-like experience. This aspect is considered by many to be integral to the drug's therapeutic effect. Remember, when used for medical purposes and in the right doses, some doctors argue that ketamine can be safe and effective in treating mental illness. There are concerns about potential addiction and health risks, especially when taken chronically in higher doses. Chronic use may lead to severe bladder damage and there are indications that abuse could result in cognitive impairment. So, that's all about ketamine. So, ketamine originally developed as an anaesthetic is being researched for its potential therapeutic effects in treating common cold and flu symptoms. No, it isn't correct. Chronic pain management. No. Treating resistant depression. Yes, this is correct. Next, high blood pressure. So, here the answer is option C, treat resistant depression. So, with this, let us move to the next topic. So, look at this previous question. They're asking about qubit. So, let us learn about quantum computing and qubits. So, what is quantum computing? See, quantum computing deals with the development of computer technologies which are centered around the principle of quantum theory. Know that quantum theory explains the nature and behavior of energy and matter on the quantum level. That is atomic and subatomic level. So, keeping this as a base, quantum computing uses subatomic particles such as electrons or photons to do their operations. Moreover, quantum computing uses a combination of bits to perform specific computational tasks. These bits are called as qubits. These help the quantum computers to function at a higher efficiency than the classical counterparts. Now, let us see how qubit do this. See, quantum computers gain much of its processing power through the ability of bits to be in multiple states at the same time. It means they can perform tasks using combination of ones, zeros and both one and zero simultaneously. Now, let us see the technology behind the working of quantum computing. They use the concepts of superposition and entanglement to solve calculations and complex problems in a matter of seconds. Here, we shall have a brief on them to understand it better. Firstly, with respect to superposition, subatomic particles like protons or electrons exhibit this strange property which is pivotal for quantum computing. Know that these particles can exist at multiple locations at the same time and this phenomenon is known as superposition. Secondly, entanglement. It is the ability of particles to instantaneously influence the behavior of another particle with whom it had an earlier interaction. Know that this will happen even when they are separated by great distance. See, quantum computers are increasingly adopted due to their relatively smaller size vis-a-vis conventional. Moreover, they do not rely on transistors like traditional machines and they also consume comparatively less powers. Now, look at this table to know more differences between quantum computers and classical computers. So, that's all about quantum computing. So, in this question, they are asking which one of the following is the context in which the term qubit is mentioned. Here, the answer is option B, quantum computing. So, with this, let us move to the next topic. Next, these are all some of the previous questions related to vaccines. UPAC is asking repeatedly on this particular topic. So, look at these questions. So, in 2022, they asked about COVID-19 vaccines like covid shield, sputnik-5 co-vaccine. And in 2021, they asked about recombinant vector vaccines. And in 2020, they asked about pneumococcal conjugate vaccines. And in 2019, they asked about hepatitis vaccine. So, there has been so many developments in the COVID-19 vaccines recently. So, let us learn a few things about COVID-19 vaccines and come back to these questions. So, let's see different types of vaccines available for COVID-19. So, there are different types of vaccines like mRNA vaccines, viral vector vaccines, inactivated vaccines, spike protein vaccines and live adornated vaccines. We shall see them one by one. See, the messenger RNA, in short, mRNA vaccines are created using messenger RNA, which is a single-strand RNA molecule. The mRNA vaccines work by introducing a piece of mRNA into the human body. By using this mRNA, the cells in our body can produce the viral protein. Subsequently, our immune system recognizes that the protein is foreign and it produces antibodies to fight the disease. The COVID vaccines, such as Pfizer and Moderna are some of the examples of mRNA vaccines. Here note that in 2023, noble price in medicine was given jointly for two people, that is Kariko and Drew Weisman, for their discoveries in mRNA technology, which was used in Pfizer, BioNTech and Modena's vaccine. Secondly, the viral vector vaccines use a modified version of a different virus as a vector to deliver the protection. Several different viruses have been used as a vector, which includes influenza, measles virus and adenovirus, that are known to cause common cold. Adenovirus is one of the viral vectors used in some COVID-19 vaccines. The COVID-19 vaccines, such as Sputnik 5, Johnson & Johnson and AstraZeneca are some of the examples of viral vector vaccines. Here the Sputnik 5 has been developed by Gamalaya National Research Institute of Epidemiology and Microbiology in Moscow. And Johnson & Johnson vaccine developed by Janssen vaccines in Leiden, Netherlands. Similarly, the Oxford-AstraZeneca vaccine known as Vax Jevira in Europe and licensed as Covid Shield in India. It is technically referred to as A2D-1-222 or CH-8U-OX-1N-COV-19. CRUM Institute of India is the manufacturing partner of Covid Shield in India. Third type is inactivated vaccine. See, these vaccines are created by inactivating a pathogen, typically using heat or chemicals such as formaldehyde or formalin. This process destroys the pathogen's ability to replicate, but the process keeps the virus or bacteria intact. So, the immune system of our body can still recognize the bacteria or virus and develop antibodies. However, inactivated vaccines tend to provide shorter protection than live vaccines and they are more likely to require boosters to create long-term immunity. So, co-vaccine is the example of inactivated vaccine and it requires booster shots to generate long-term immunity. So, co-vaccine was developed by Bharat Biotech which is located in Hyderabad in collaboration with the Indian Council of Medical Research, National Institute of Virology, Pune. Next, spike protein vaccines. As you all know, the members of coronavirus family have a sharp bump that protrude from the surface of their outer envelopes. Those bumps are known as spike proteins. These spike proteins allow the virus to enter the cells in the body so that it can replicate and cause disease. Using the spike protein vaccine, the spike protein alone is given to the body and the body is expected to develop an immune response against the injected spike protein. Therefore, when the real virus attempts to infect the body, it will already have an immune response ready that will make it unlikely for the person to fall severely ill. Corbvax is an example for spike protein vaccine. Corbvax is India's indigenously developed receptor binding domain, RBD protein subunit vaccine. It was developed by Biological Elimiter. Those who have received COVID shield or co-vaccine as their first or second dose for COVID-19 can take Corbvax as the third booster shot. Finally, live atonated vaccine. Live vaccines use a weakened or atonated form of the germ that causes the disease because these vaccines are so similar to the natural infection that they help prevent and they can create strong and long-lasting immune response. So that's all about COVID-19 vaccines. So in this previous request, they're asking about COVID-19 vaccines. The Serum Institute of India produced COVID-19 vaccine named COVID shield using mRNA platform. This statement is incorrect because COVID shield was not developed by mRNA method. Rather, it was developed under viral vector vaccines method. Next, the Sputnik 5 vaccine is manufactured using vector-based platform. Yes, this statement is correct. Next, co-vaccine is an inactivated pathogen-based vaccine. Yes, this statement is also correct. Here, they're asking which are all the statements are correct. So the answer is option B213. So in this question, with reference to the recent developments regarding re-component vector vaccines, consider the following statements. First, genetic engineering is applied in the development of these vaccines. Yes, this statement is correct. Next, bacteria and virus are used as a vector. This statement is also correct. So here the answer is option C1 and 2. Next, in this question, what is the importance of using pneumococcal conjugate vaccine in India? These vaccines are effective against pneumonia as well as meningitis and sepis. This statement is correct. Dependence on antibiotics that are not effective against drug-resistant bacteria can be reduced. This statement is also correct. These vaccines have no side effects and cause no allergic reactions. This statement is very extreme and we cannot surely say there will not be any side effects and allergic reactions. So obviously the third statement is incorrect. So the answer is option B1 and 2 only. So in this question, they're asking what are all not correct. Here the answer is option B because here hepatitis C has a vaccine but hepatitis B does not have any vaccine as of now. So let us move on to the next topic. Here in this question, they're asking about lithium. First, let us learn a few things about lithium and come back to this question. So lithium is the third chemical element in the periodic table. It is soft in nature and appears shiny with silvery white colour. It is actually a non-ferrous alkali metal and it has the lowest density compared to other metals. It is highly reactive and does not occur freely in nature. Also note that lithium has a high specific heat capacity. Here specific heat capacity is the amount of heat required to change the temperature of a substance by 1 degree. For example, we need more heat to warm one unit of water by 1 degree Celsius when compared to heating one unit of air by 1 degree Celsius. So this is about specific heat. Coming back to lithium, lithium has the lowest melting point of all the metals and has high boiling point. Talking about their global distribution, lithium makes up mere 0.007% of the earth crust. Latin American nations primarily, CHIL and ARGENTINA accounts for 30 to 35% of world's supplies. CHIL alone has 11% of world's lithium reserves and supplies 26% of the global lithium requirements. While Argentina with nearly one-fifth of global resources supplies about 6% of the requirements. Bolivia, another Latin American country, has the richest known lithium deposits in the world. Due to the contribution of these three Latin American countries, they are together known as lithium triangle of the world. Apart from this, Australia is among the other large lithium producers globally. Some of the other countries with largest lithium deposits are given in this picture. You can go through it. Talking about the lithium reserves distribution in India, they are concentrated in states like Chattisgarh, Nagaland, Meghalaya, Arunachal Pradesh, Karnataka, Rajasthan, Jharkhand and Andhra Pradesh. Recently, there was a discovery of 5.9 million metric tons of lithium in the Salil-Aimana area of Jammu Ghashmir. This is the first major lithium reserve that has been found in India. Talking about the applications of lithium, lithium is often referred to as white gold due to its market value. Remember, lithium is found in two forms. One is lithium hydroxide and another one is lithium carbonate. Both are used in batteries and electric vehicles. Lithium carbonate has a wide range of uses, since they are lightweight and can quickly recharge. So, it is used in manufacturing of EV batteries. Lithium carbonate is even listed by the World Health Organization as an essential medication for treating bipolar disorder. Lithium carbonate can also be converted into lithium hydroxide, which is preferred in manufacturing, high-performing and long-lasting EV batteries. So, in this question, consider the following statements about lithium. Lithium is the lightest metal and has highest specific heat capacity of all solid elements. This is correct. Lithium occurs freely in nature and is found in large quantities across the globe. No, this is incorrect. The lithium triangle comprising of Argentina, China and Bolivia. Yes, this is correct. India's major lithium reserves have been discovered in the Salil-Aimana area of Jammu Ghashmir. Yes, this statement is correct. So, the answer is option C, 1, 3 and 4 only. Look at this question. Here, they are asking the diseases and their causes. Here, Huntington's disease was frequently in use. First, let us see Huntington's disease and come back to this question. So, what is Huntington's disease? Huntington's disease is an inherited disease that causes the degeneration of nerve cells in the brain. It is also called as Huntington's Chorea. Note that it is an autosomal dominant disorder. This means it is linked to a defect in a gene on one of the autosomal chromosomes, specifically chromosome 4 and does not involve the sex chromosomes. This changes the Huntington that is HTT gene and causes Huntington's disease. The HTT gene is responsible to make a protein called Huntington. This protein helps your nerve cells to function. So, if someone has Huntington's disease, then their DNA will lack the information required to make the Huntington's protein. As a result, these proteins grow in an abnormal shape and destroy the neurons. What happens if neurons start to degrade? We know that neurons communicate with each other through electrical and chemical signals. When neurons are degrade, the transmission of signals becomes compromised. This can result in disruptions to sensory perception, motor control and cognitive functions. Otherwise, the person might have uncontrolled movements like jerking or twitching, loss of coordination, trouble in walking, difficulty in swallowing, memory loss and slurred speech. All these happen due to the stop in signals shared between the neurons. Hope you get it. Remember, the disease is progressive in nature, meaning it gets worse over time. This is the cause for the disease. Know that Huntington's disease cannot be cured, but healthcare providers can offer medications to help with certain symptoms. So, that's all about Huntington's Korea. Now, moving on to the question. Consider the following pairs. First, Huntington's disease. This is caused by the expansion of CAG repeats in the HDD gene. So, first is incorrect. Sickle cell anemia, which was caused by the mutation in the HPB gene on chromosome 11. Next, Down syndrome, which is caused by trizomy of chromosome 21. This is correct. Cystic fibrosis is caused by the mutation in the CFTR gene. Here, first and fourth pair are correct. So, the answer is option B, two pairs. Now, let's move to the next topic. Look at this question. Here, they are asking about the principle of piezoelectricity. So, let us see about piezoelectricity and come back to this question. So, what is piezoelectric effect? It is a phenomenon whereby some materials can generate an electric current in response to the mechanical stress. For example, materials like quartz, ceramics such as lead, zirconate, titanate, certain biological substances like bone, tendons, etc. So, this piezoelectric effect was discovered in 1880 in quartz by Jacquels and Piricuri. So, let us see how this happens. Know that when the material is subjected to a mechanical stress, it will make the molecules of the material to become polarized. It means positive and negative charges within the material are separated from each other. Moreover, when this polarization occurs, an electric potential is generated across the material. And if the material is connected to the circuit, the current can flow through it. Moreover, we should be aware of the phenomenon called reverse piezoelectric effect. In this effect, a crystal becomes mechanically stressed or deformed in shape when a voltage is applied across its end. Thus, piezoelectric materials allow the conversion of energy from mechanical domain to the electric domain and vice versa. Now, let us see some of the piezoelectric materials. So, there are wide varieties of materials which exhibit this phenomenon. This includes natural quartz crystals, semi-crystalline, polyvinylidene, polymer, cane sugar, quartz, ratchel, salt, topaz, bone and even wood. So, now let us see what is the application of piezoelectric materials. See, piezoelectric materials are used in varieties of applications such as in sensors, actuators and energy harvesting devices, etc. Know that they are used in ultrasonic applications like intrusion detectors and alarms. They are also employed at AF, that is, audio frequencies, as pickups, microphones, airphones, beepers and buzzers. Recently, scientists from Indian Institute of Technology, Madras and the Defence Research and Development Organisation, DRO, developed piezoelectric ME-MS, that is, micro-electromechanical system technology for underwater communication. So, this will add Indian underwater combat capabilities. So, this is all about piezoelectric effect. Now, moving on to the question, which of the following statements correctly describes the principle of piezoelectricity? Here, the answer is option A. Piezoelectricity is the electrical charge that accumulates in certain solid materials in response to applied mechanical stress. That's it. Now, let us move to the next topic. Look at this question. Here, they are asking about Agnipath scheme. So, let us see some of the details about Agnipath scheme and come back to this question. So, what is the Agnipath scheme? Agnipath is a defence personnel recruitment scheme under which 45,000 to 50,000 soldiers will be recruited annually. They are also called as Agnivis. Here, note that most of them will leave the service in just four years. Of the total annual recruits, only 25% will be allowed to continue for another 15 years under permanent commission. The most important thing is to note here is that the new system of recruitment under Agnipath scheme is only for personnel below the officer ranks. Now, coming to the eligibility criteria, aspirants between the age of 17.5 years and 21 years will be eligible to apply. For the recruitment year 2022-2023, the upper age limit has been increased from 21 to 23 years old. The recruitment standards will remain the same and the recruitment will be done twice a year through recruitment rallies organized across the country. Now, coming to the question, what happens after the selection? One selector, the aspirants will go through training for six months and then will be deployed for three and a half years to perform their duties as defence personnel. During this period, they will get a starting salary of 30,000 rupees along with the additional benefits which will go up to 40,000 by the end of the four year service. Importantly, during this period, 30% of their salary will be set aside under the SEVA NIDI program and the government will contribute an equal amount every month and it will also have interest. At the end of the four years, each soldier will get 11.71 lakh as the lump sum amount which will be tax free. They also get 48 lakh life insurance cover for four years. In case of death, the payout will be over 1 crore including pay for the unserved tenure. However, as earlier said, after four years, only 25% of the batch will be recruited back into their respective service for the period of 15 years. For those who are reselected, the initial four year period will not be considered for the recruitment benefits. So, that's all about Agnipat scheme. So, moving on to the question, which one of the following statements is not correct regarding the Agnipat scheme? Here the answer is A. The scheme envisages recruitment of soldiers annually, half of whom will be retained after the period of four years. This is incorrect because only 25% of soldiers will be retained after the four years and all other statements are correct. So, the PDF of this summary is in the description. Please download it and use it for your future reference. With this, second part of science and technology discussion is over. Your next summary will be posted on next Monday. So, let's wind up for today. For more information regarding UPSC preparation, do like, share and subscribe to Shankar Agis Academy. Now, thank you so much for watching.