QUASARS

1. Context 

2. About Quasars

• Quasars short for "quasi-stellar radio sources" were first discovered six decades ago. 
• They are located in supermassive black holes, which sit in the centre of galaxies.
• As a supermassive black hole feed on gas and dust, it releases extraordinary amounts of energy in the form of radiation, resulting in a quasar.
• The mechanisms that trigger quasars have been hotly debated. Some studies suggest galaxy mergers are responsible, while others found little evidence to support the theory.

3. Findings of the Study

• The mixed results are because the images used in many studies were not sensitive enough to detect them.
• To tackle this issue, the image is a large sample of quasars with the appropriate depth to identify these signatures.
• To do this, researchers relied on the Isaac Newton Telescope in La Palma in the Canary Islands. They compared 48 galaxies that host quasars with over 100 non-quasar galaxies.
• Galaxies that host a quasar showed morphological features that are consistent with galaxy mergers, the researchers noted.
• When galaxies collide, it pushes the gas from the outer reaches of galaxies to the centre. And as the supermassive black hole gorges on the gas, it releases ferocious fountains of energy in the form of radiation, leading to the quasar.
• These results present strong evidence that galaxy interactions are the dominant trigger for quasars in the local universe.
• However, they are unlikely to be the sole factor, the researchers wrote in their study.

4. Significance of quasars

• When a quasar is ignited, it can drive the rest of the gas out of the galaxy. 
• The radiation from these objects is so intense that intervening gas within the galaxy feels a pressure that moves it away from the quasar in the nucleus, driving "outflows" of material.
• In extreme cases, a significant fraction of the total gas in a galaxy gets displaced. This has drastic consequences on star formation. 
• Also, the collision of the Milky Way galaxy with the Andromeda galaxy could likely trigger a quasar, the scientists predict in their study.
• Quasars are one of the most extreme phenomena in the universe and what we see is likely to represent the future of our own Milky Way galaxy when it collides with the Andromeda galaxy in about five billion years.
• It's exciting to observe these events and finally understand why they occur but thankfully, Earth won't be anywhere near one of these apocalyptic episodes for quite some time.
• Further, quasars act as "cosmic lighthouses" allowing researchers to see the outer reaches of the universe.
• NASA's James Webb Space Telescope will study the earliest galaxies in the universe.
• The telescope is capable of detecting light from even the most distant quasars, emitted nearly 13 billion years ago.
• The galaxy collisions are very important for triggering this activity in galaxies closer to us, we can consider whether these events were also important for igniting quasars in earlier epochs of the universe.

Source: Down to Earth

GENOME MAPPING

1. Context

2. Human Genome Project (HGP)

• One of the most comprehensive genome mapping projects in the world is the Human Genome Project (HGP), which began in 1990 and reached completion in 2003.
• The international project, which was coordinated by the National Institutes of Health and the US Department of Energy, was undertaken with the aim of sequencing the human genome and identifying the genes that contain it.
• The project was able to identify the locations of many human genes and provide information about their structure and organization.

3. Genome Mapping

• Gene mapping refers to the technique used to identify a gene's location and distance between genes.
• The distances between various sites inside a gene can also be described through gene mapping.
• Placing several molecular markers at specific locations on the genome is the fundamental element of all genome mapping.
• There are many types of molecular markers. When creating genome maps, genes can be observed as a particular class of genetic markers mapped similarly to other markers.

4. Types of Gene Mapping

• Genetic linkage maps and physical maps are the two main categories of "Maps" used in gene mapping.
• Both maps consist of genetic markers and gene loci. While physical maps involve actual physical distances, often measured in a number of base pairs, distances of genetic maps are based on genetic linkage information.
• There are many gene mapping methods, including comparative, physical, and genetic-linkage mapping. However, physical, and genetic-linkage mapping are more common.

5. What does genome mapping tell us?

• According to the Human Genome Project, there are estimated to be over 20,500 human genes.
• Genome refers to an organism's complete set of DNA, which includes all its genes, and mapping these genes simply means finding out the location of these genes in a chromosome.
• In humans, each cell consists of 23 pairs of chromosomes for a total of 46 chromosomes, which means that for 23 pairs of chromosomes in each cell, there are roughly 20,500 genes located on them.
• Some of the genes are lined up in a row on each chromosome, while others are lined up quite close to one another and this arrangement might affect the way they are inherited.
• For Example, if the genes are placed sufficiently close together, there is a probability that they get inherited as a pair.
• Genome mapping, therefore, essentially means figuring out the location of a specific gene on a particular region of the chromosome and also determining the location of relative distances between other genes on that chromosome.
• Significantly, genome mapping enables scientists to gather evidence if a disease transmitted from the parent to the child is linked to one or more genes.
• Furthermore, mapping also helps in determining the particular chromosome which contains that gene and the location of that gene in the chromosome.
• According to the National Human Genome Research Institute (NHGRI), genome maps have been used to find out genes that are responsible for relatively rare, single-gene inherited disorders such as cystic fibrosis and Duchenne muscular dystrophy.
• Genetic maps may also point out scientists to the genes that play a role in more common disorders and diseases such as asthma, cancer, and heart disease among others.

6. Why it is more important?

• A complete human genome makes it easier to study genetic variation between individuals or between populations.
• A genome refers to all of the genetic material in an organism, and the human genome is mostly the same in all people, but a very small part of the DNA does vary between one individual and another.
• By constructing a complete human genome, scientists can use it for reference while studying the genome of various individuals, which would help them understand which variations, if any, might be responsible for the disease.

7. What was missing?

• The genetic sequence made available in 2003 from the Human Genome Project, an international collaboration between 1990 and 2003, contained information from a region of the human genome known as the euchromatin.
• Here, the chromosome is rich in genes, and the DNA encodes for protein. The 8% that was left out was in the area called heterochromatin. This is a smaller portion of the genome and does not produce protein. 
• There were at least two key reasons why heterochromatin was given lower priority. This part of the genome was thought to be “junk DNA” because it had no clear function.
• Besides, the euchromatin contained more genes that were simpler to sequence with the tools available at the time.
• Now, the fully sequenced genome is the result of the efforts of a global collaboration called the Telomere-2- Telomere (T2T) project.
• The invention of new methods of DNA sequencing and computational analysis helped complete the reading of the remaining 8% of the genome. 

8. What is in the 8%?

• The new reference genome, called T2TCHM13, includes highly repetitive DNA sequences found in and around the telomeres (structures at the ends of chromosomes) and the centromeres (at the middle section of each chromosome).
• The new sequence also reveals long stretches of DNA that are duplicated in the genome and are known to play important roles in evolution and disease.
• The fact that the sequences are repetitive is enlightening. The findings have revealed a large number of genetic variations, and these variations appear in large part within these repeated sequences.
• A significant amount of human genetic material turns out to be long, repetitive sections that occur over and over.
• Although every human has some repeats, not everyone has the same number of them. And the difference in the number of repeats is where most of the human genetic variation is found,” the University of Connecticut said in a press release.
• Many of the newly revealed regions have important functions in the genome even if they do not include active genes. 

Previous year Question

1. With reference to agriculture in India, how can the technique of 'genome sequencing', often seen in the news, be used in the immediate future? (UPSC 2017) 1. Genome sequencing can be used to identify genetic markers for disease resistance and drought tolerance in various crop plants. 2. This technique helps in reducing the time required to develop new varieties of crop plants. 3. It can be used to decipher the host-pathogen relationships in crops. Select the correct answer using the code given below: A. 1 only B. 2 and 3 only C. 1 and 3 only D. 1, 2 and 3 Answer: D

 

Source: The Indian Express

DEOXYRIBONUCLEIC ACID (DNA)

 

1. Context

Seventy years ago, two male scientists, Francis Crick, and James Watson, proclaimed they had discovered the secret of life: The structure of DNA. Since then, history has acknowledged how Rosalind Franklin was sidelined. But new archive evidence has cast doubt on the widely accepted narrative that Franklin collected an all-important image but didn’t appreciate the meaning of what she was looking at.

2. Deoxyribonucleic Acid (DNA)

• Deoxyribonucleic acid (abbreviated DNA) is the molecule that carries genetic information for the development and functioning of an organism.
• DNA is made of two linked strands that wind around each other to resemble a twisted ladder a shape known as a double helix.
• Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups.
• Attached to each sugar is one of four bases: adenine (A), cytosine (C), guanine (G), or thymine (T).
• The two strands are connected by chemical bonds between the bases: adenine bonds with thymine, and cytosine bonds with guanine.
• The sequence of the bases along DNA’s backbone encodes biological information, such as the instructions for making a protein or RNA molecule. 

Image Source: National Human Genome Research Institute

3. DNA Structure and Function

• DNA is the information molecule. It stores instructions for making other large molecules, called proteins.
• These instructions are stored inside each of your cells, distributed among 46 long structures called chromosomes.
• These chromosomes are made up of thousands of shorter segments of DNA, called genes. Each gene stores the directions for making protein fragments, whole proteins, or multiple specific proteins.
• DNA is well-suited to perform this biological function because of its molecular structure, and because of the development of a series of high-performance enzymes that are fine-tuned to interact with this molecular structure in specific ways.
• The match between DNA structure and the activities of these enzymes is so effective and well-refined that DNA has become, over evolutionary time, the universal information-storage molecule for all forms of life.
• Nature has yet to find a better solution than DNA for storing, expressing, and passing along instructions for making proteins.

3.1 Molecular structure of DNA

• In order to understand the biological function of DNA, you first need to understand its molecular structure.
• This requires learning the vocabulary for talking about the building blocks of DNA, and how these building blocks are assembled to make DNA molecules.

3.2 DNA Molecules are Polymers

• Polymers are large molecules that are built up by repeatedly linking together smaller molecules, called monomers.
• Think of how a freight train is built by linking lots of individual boxcars together, or how this sentence is built by sticking together a specific sequence of individual letters (plus spaces and punctuation).
• In all three cases, the large structure of a train, a sentence, and a DNA molecule is composed of smaller structures that are linked together in non-random sequences boxcars, letters, and, in the biological case, DNA monomers.

3.3 DNA Monomers are called Nucleotides

• Just like the sentence “polymer” is composed of the letter “monomers,” a DNA polymer is composed of monomers called nucleotides.
• A molecule of DNA is a bunch of nucleotide monomers, joined one after another into a very long chain.

4. Four Nucleotide Monomers

• The English language has a 26-letter alphabet. In contrast, the DNA “alphabet” has only four “letters,” the four nucleotide monomers.
• They have short and easy-to-remember names: A, C, T, G. Each nucleotide monomer is built from three simple molecular parts: a sugar, a phosphate group, and a nucleobase. (Don’t confuse this use of “base” with the other one, which refers to a molecule that raises the pH of a solution; they’re two different things.)

5. The sugar and acid in all four monomers are the same

• All four nucleotides (A, T, G, and C) are made by sticking a phosphate group and a nucleobase to a sugar.
• The sugar in all four nucleotides is called deoxyribose. It’s a cyclical molecule most of its atoms are arranged in a ring structure.
• The ring contains one oxygen and four carbons. A fifth carbon atom is attached to the fourth carbon of the ring.
• Deoxyribose also contains a hydroxyl group (-OH) attached to the third carbon in the ring.

6. Four Nucleotide Monomers are distinguished by their bases

Each type of nucleotide has a different nucleobase stuck to its deoxyribose sugar.

• A nucleotide contains adenine
• A nucleotide contains thymine
• G nucleotide contains guanine
• C nucleotide contains cytosine

All four of these nucleobases are relatively complex molecules, with the unifying feature that they all tend to have multiple nitrogen atoms in their structures. For this reason, nucleobases are often also called nitrogenous bases.

7. DNA Fingerprinting

• It is known that every individual has unique fingerprints. These occur at the tips of the fingers and have been used for identification for a long time but these can be altered by surgery.
• A sequence of bases on DNA is also unique for a person and information regarding this is called DNA fingerprinting. It is the same for every cell and cannot be altered by any known treatment.
• DNA fingerprinting is now used (i) in forensic laboratories for the identification of criminals. (ii) to determine the paternity of an individual. (iii) to identify the dead bodies in any accident by comparing the DNAs of parents or children. (iv) to identify racial groups to rewrite biological evolution.

8. Recombinant DNA

• Recombinant DNA (rDNA) molecules are DNA molecules formed by laboratory methods of genetic recombination (such as molecular cloning) to bring together genetic material from multiple sources, creating sequences that would not otherwise be found in the genome.
• Recombinant DNA is possible because DNA molecules from all organisms share the same chemical structure. They differ only in the nucleotide sequence within that identical overall structure.
• In most cases, organisms containing recombinant DNA have apparently normal phenotypes. That is, their appearance, behavior, and metabolism are usually unchanged.

For Prelims: Deoxyribonucleic acid (DNA), adenine (A), cytosine (C), guanine (G), or thymine (T), RNA molecule, Polymers, Nucleotide, Nucleotide Monomers, DNA Fingerprinting and Recombinant DNA (rDNA). For Mains: 1. What is Deoxyribonucleic acid (DNA)? Discuss the structure and function of the Deoxyribonucleic acid (DNA) and explain how it is different from RNA.(250 Words)

 

Previous year Question

 

1. Recombinant DNA technology (Genetic Engineering) allows genes to be transferred (UPSC 2013) 1. across different species of plants 2. from animals to plants 3. from microorganisms to higher organisms Select the correct answer using the codes given below. A. 1 only B. 2 and 3 only C. 1 and 3 only D. 1, 2 and 3 Answer: D   2. With reference to the recent developments in science, which one of the following statements is not correct? (UPSC 2019) A. Functional chromosomes can be created by joining segments of DNA taken from cells of different species. B. Pieces of artificial functional DNA can be created in laboratories. C. A piece of DNA taken out from an animal cell can be made to replicate outside a living cell in a laboratory. D. Cells taken out from plants and animals can be made to undergo cell division in laboratory Petri dishes. Answer: A   3. Consider the following statements: (UPSC 2022) DNA Barcoding can be a tool to: 1. assess the age of a plant or animal. 2. distinguish among species that look alike. 3. identify undesirable animal or plant materials in processed foods. Which of the statements given above is/are correct? A. 1 only B. 3 only C. 1 and 2 D. 2 and 3 Answer: D

 

Source: Down to Earth

QUANTUM COMPUTING

1. Context 

India decided to join in this global effort in a big way, by setting up a Rs 6,000 crore National Mission on Quantum Technologies and Applications.

The development of homegrown quantum computers is one of the major objectives of the mission. 

 

2. About quantum computing

• Quantum computing is a rapidly-emerging technology that harnesses the laws of quantum mechanics to solve problems too complex for classical computers. 
• IBM Quantum makes real quantum hardware a tool scientists only began to imagine three decades ago available to hundreds of thousands of developers.
• Engineers deliver ever-more-powerful superconducting quantum processors at regular intervals, alongside crucial advances in software and quantum-classical orchestration.
• This work drives toward the quantum computing speed and capacity necessary to change the world. 
• These machines are very different from the classical computers that have been around for more than half a century.

Image Source: IBM

3. Need for quantum computers

• For some problems, supercomputers aren’t that super. When scientists and engineers encounter difficult problems, they turn to supercomputers.
• These are very large classical computers, often with thousands of classical CPU and GPU cores. However, even supercomputers struggle to solve certain kinds of problems.
• If a supercomputer gets stumped, that's probably because the big classical machine was asked to solve a problem with a high degree of complexity. When classical computers fail, it's often due to complexity
• Complex problems are problems with lots of variables interacting in complicated ways.
• Modelling the behaviour of individual atoms in a molecule is a complex problem, because of all the different electrons interacting with one another.
• Sorting out the ideal routes for a few hundred tankers in a global shipping network is complex too.

4. Quantum computers work

• Quantum computers are elegant machines, smaller and requiring less energy than supercomputers.
• An IBM Quantum processor is a wafer not much bigger than the one found in a laptop.
• And a quantum hardware system is about the size of a car, made up mostly of cooling systems to keep the superconducting processor at its ultra-cold operational temperature.
• A classical processor uses bits to perform its operations. A quantum computer uses qubits (CUE-bits) to run multidimensional quantum algorithms.

4.1. Superfluids

• A desktop computer likely uses a fan to get cold enough to work.
• Quantum processors need to be very cold about a hundredth of a degree above absolute zero.
• To achieve this, we use super-cooled superfluids to create superconductors.

4.2. Superconductors

• At those ultra-low temperatures, certain materials in our processors exhibit another important quantum mechanical effect: electrons move through them without resistance. This makes them "superconductors." 
• When electrons pass through superconductors they match up, forming "Cooper pairs."
• These pairs can carry a charge across barriers, or insulators, through a process known as quantum tunnelling.
• Two superconductors placed on either side of an insulator form a Josephson junction.

4.3. Control

• Our quantum computers use Josephson junctions as superconducting qubits.
• By firing microwave photons at these qubits, we can control their behaviour and get them to hold, change, and read out individual units of quantum information.

4.4. Superposition

• A qubit itself isn't very useful. But it can perform an important trick: placing the quantum information it holds into a state of superposition, which represents a combination of all possible configurations of the qubit.
• Groups of qubits in superposition can create complex, multidimensional computational spaces. Complex problems can be represented in new ways in these spaces.

4.5. Entanglement

• Entanglement is a quantum mechanical effect that correlates the behaviour of two separate things.
• When two qubits are entangled, changes to one qubit directly impact the other.
• Quantum algorithms leverage those relationships to find solutions to complex problems.

5. Making quantum computers useful

• Right now, IBM Quantum leads the world in quantum computing hardware and software. It is a clear and detailed plan to scale quantum processors, overcomes the scaling problem, and build the hardware necessary for quantum advantage.
• Quantum advantage will not be achieved with hardware alone.
• IBM has also spent years advancing the software that will be necessary to do useful work using quantum computers.
• They developed the Qiskit quantum SDK. It is open-source, python-based, and by far the most widely-used quantum SDK in the world.
• The Qiskit Runtime is the most powerful quantum programming model in the world.
• Achieving quantum advantage will require new methods of suppressing errors, increasing speed, and orchestrating quantum and classical resources.

 

For Prelims: Quantum computing, supercomputers, Qiskit Runtime, IBM, National Mission on Quantum Technologies and Applications, superconductors,  For Mains:  1. What is Quantum computing? Discuss the need for Quantum Computers in emerging countries like India. (250 Words) 2. What are quantum computers and how are they different from conventional computers? Where does India stand in the race to build quantum computers that can realise their full potential? (250 Words)

 

 

Previous Year Questions   1. India's first Supercomputer is  (TSPSC AEE 2015) A. Aditya B. Param Yuva C.  Param D. Vikram-100 Answer: C   2. What is the full form of IBM? (SSC Steno  2017)  A. International Business Machine B. Indian Beta Machine C. Integral Business Machine D. Internal Beta Machine   Answer: A   3. Which one of the following is the context in which the term "qubit" is mentioned? (UPSC 2022)  A. Cloud Services B. Quantum Computing C. Visible Light Communication Technologies D. Wireless Communication Technologies   Answer: B   4. Quantum computing uses  (ACC 124 CGAT  2021) A. Qubit B. Bits C. Bytes D. Qubytes   Answer: A

 

Source: IBM

 

CONSTITUENT ASSEMBLY 

 

 

 

1. Background

The Constitution of India was drafted by the Constituent Assembly. The idea was initially proposed in December 1934 by M.N. Roy, a pioneer of the Communist movement in India and an advocate of radical democracy.

It became an official demand of the Indian National Congress in 1935 and was officially adopted in the Lucknow session in April 1936 presided by Jawaharlal Nehru, who also drafted the Objectives Resolution.

The proceedings of the Constituent Assembly show the richness of ideas that characterised it. The Drafting Committee was presided over by B.R. Ambedkar

2. Composition of the Council

It was constituted in 1946 ,Some of the important aspects related to this are:

1. Total strength of the assembly: 389
2. 296 seats for British India and 93 seats to princely states
3. 292 seats allocated for British India were to be from eleven governor’s provinces and four from Chief commissioner’s provinces
4. Seats were allocated based in proportion to their respective population.
5. Seats allocated to each British province were to be decided among the three principal communities- Muslims, Sikhs and general
6. Representatives of each communities were to be elected by members of that community in the provincial legislative assembly and voting was to be by the method of proportional representation by means of single transferrable vote
7. Representatives of princely states were to be nominated by head of these princely states

• Partly elected and partly nominated
• Indirect election by provincial assemblies who themselves were elected on a limited franchise
• Though indirect mode of election, it included representatives from all sections of the society

3. Committees of the Constituent Assembly

Several committees were constituted to perform the various tasks associated with framing of the Constitution. Some of the major and minor constituent assembly committees are given below:

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