2021 Archives

171. Consider the following : Bacteria Fungi Virus Which of the ab

Consider the following :

Bacteria
Fungi
Virus

Which of the above can be cultured in artificial/synthetic medium?

[amp_mcq option1=”1 and 2 only” option2=”2 and 3 only” option3=”1 and 3 only” option4=”1, 2 and 3″ correct=”option1″]

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Bacteria and Fungi can be cultured in artificial/synthetic medium.

– Bacteria and Fungi are generally heterotrophic organisms that can obtain nutrients from their environment. They can be grown in laboratory settings using various artificial media (like nutrient broth, agar plates, etc.) that provide the necessary nutrients, carbon sources, and growth factors.
– Viruses, on the other hand, are obligate intracellular parasites. They lack the cellular machinery required for replication and must infect living host cells to reproduce. They cannot replicate or be cultured in artificial/synthetic media alone. Instead, viruses are cultured using techniques involving live cells or tissues, such as cell cultures, embryonated eggs, or living animals.

Artificial media are typically composed of a defined mixture of salts, sugars, amino acids, vitamins, and sometimes complex organic substances like peptone or yeast extract. The composition of the medium can be adjusted to suit the specific nutritional requirements of different types of bacteria or fungi.

172. In a pressure cooker, the temperature at which the food is cooked depe

In a pressure cooker, the temperature at which the food is cooked depends mainly upon which of the following?

Area of the hole in the lid
Temperature of the flame
Weight of the lid

Select the correct answer using the code given below.

[amp_mcq option1=”1 and 2 only” option2=”2 and 3 only” option3=”1 and 3 only” option4=”1, 2 and 3″ correct=”option3″]

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The temperature at which food is cooked in a pressure cooker depends mainly upon the area of the hole in the lid and the weight of the lid.

– A pressure cooker works by creating a sealed environment that traps steam, increasing the internal pressure.
– The boiling point of water increases with pressure. At standard atmospheric pressure (1 atm), water boils at 100°C (212°F). In a pressure cooker, the pressure can rise to about 2 atm (or more), raising the boiling point to around 120-125°C (248-257°F).
– The maximum pressure inside the cooker is regulated by a pressure release valve, which typically consists of a small hole or vent in the lid covered by a weight or spring mechanism.
– The pressure at which steam is released depends directly on the weight placed on the vent and inversely on the area of the vent hole under the weight. A heavier weight or a smaller hole area will result in higher pressure and thus a higher cooking temperature.
– The temperature of the flame affects the *rate* at which the water heats up and turns into steam, and thus how quickly the desired pressure is reached. However, once the pressure regulator starts venting steam, the temperature inside stabilizes at a level determined by the pressure, not the flame temperature (as long as the heat input is sufficient to maintain that pressure).
– Therefore, the main factors determining the cooking temperature are the weight of the lid (specifically the pressure regulator) and the area of the hole it covers, which together regulate the internal pressure.

Cooking at a higher temperature under pressure significantly reduces cooking time compared to boiling at atmospheric pressure. Different pressure cookers and their regulators are designed to operate at specific pressures, typically “low” or “high” pressure settings, corresponding to different weights or spring tensions.

173. Bollgard I and Bollgard II technologies are mentioned in the context

Bollgard I and Bollgard II technologies are mentioned in the context of

[amp_mcq option1=”clonal propagation of crop plants” option2=”developing genetically modified crop plants” option3=”production of plant growth substances” option4=”production of biofertilizers” correct=”option2″]

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UPSC IAS – 2021

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Bollgard I and Bollgard II technologies are used in the context of developing genetically modified crop plants.

– Bollgard I and Bollgard II are trade names for genetically modified (GM) cotton seeds developed by Monsanto (now part of Bayer).
– These technologies involve introducing genes from the bacterium *Bacillus thuringiensis* (Bt) into the cotton plant’s genome.
– The Bt genes (specifically *cry1Ac* in Bollgard I and *cry1Ac* and *cry2Ab* in Bollgard II) produce proteins that are toxic to certain insect pests, particularly the cotton bollworm (Helicoverpa armigera) and other lepidopteran pests.
– This genetic modification makes the cotton plant resistant to these pests, reducing the need for chemical insecticides and improving yields. This is a classic example of genetic modification for pest resistance in crops.

Bollgard cotton is widely cultivated in India and other parts of the world. While beneficial for pest control, its use has also raised concerns about pest resistance evolution and environmental impacts.

174. In the context of hereditary diseases, consider the following statemen

In the context of hereditary diseases, consider the following statements :

Passing on mitochondrial diseases from parent to child can be prevented by mitochondrial replacement therapy either before or after in vitro fertilization of egg.
A child inherits mitochondrial diseases entirely from mother and not from father.

Which of the statements given above is/are correct?

[amp_mcq option1=”1 only” option2=”2 only” option3=”Both 1 and 2″ option4=”Neither 1 nor 2″ correct=”option3″]

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Statement 1 is correct, and statement 2 is correct.

– Statement 1: Mitochondrial Replacement Therapy (MRT), including Pronuclear Transfer or Maternal Spindle Transfer techniques, aims to prevent the transmission of mitochondrial diseases from mother to child. These procedures involve transferring the nucleus from the affected mother’s egg (or zygote) into a donor egg (or zygote) that has had its nucleus removed but retains healthy mitochondria. This can be performed either before or after fertilization (in vitro fertilization).
– Statement 2: Mitochondria, organelles responsible for energy production within cells, contain their own DNA (mtDNA). In humans, mtDNA is almost exclusively inherited from the mother because the egg contributes the vast majority of cytoplasm (containing mitochondria) to the zygote, while the sperm contributes primarily nuclear DNA. Therefore, mitochondrial diseases are maternally inherited.

Mitochondrial diseases are a group of chronic, genetic disorders that occur when mitochondria fail to produce enough energy for the body to function properly. MRT is a relatively new and complex technique with ethical and regulatory considerations, approved in some countries under specific conditions.

175. With reference to recent developments regarding Recombinant Vector Vac

With reference to recent developments regarding Recombinant Vector Vaccines, consider the following statements:

Genetic engineering is applied in the development of these vaccines.
Bacteria and viruses are used as vectors.

Which of the statements given above is/are correct?

[amp_mcq option1=”1 only” option2=”2 only” option3=”Both 1 and 2″ option4=”Neither 1 nor 2″ correct=”option3″]

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The correct answer is C) Both 1 and 2.

– Statement 1 is correct. Recombinant vector vaccines are developed using genetic engineering techniques. A gene from the target pathogen (e.g., the spike protein gene of SARS-CoV-2) is inserted into the genome of a harmless vector organism (usually a virus or bacterium). This process involves genetic manipulation.
– Statement 2 is correct. Both viruses (e.g., adenoviruses, vaccinia virus) and bacteria (e.g., attenuated Salmonella, Listeria) are used as vectors in the development of recombinant vector vaccines. The vector delivers the pathogen’s genetic material into host cells to trigger an immune response.

– Recombinant vector vaccines are one of the modern approaches to vaccine development. They combine elements of traditional vaccine approaches with genetic engineering, offering advantages in terms of safety and the ability to elicit strong immune responses. Several COVID-19 vaccines (e.g., AstraZeneca, Sputnik V, Johnson & Johnson) are examples of viral vector vaccines.

176. The black cotton soil of India has been formed due to the weathering

The black cotton soil of India has been formed due to the weathering of

[amp_mcq option1=”brown forest soil” option2=”fissure volcanic rock” option3=”granite and schist” option4=”shale and limestone” correct=”option2″]

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The correct answer is B) fissure volcanic rock.

– The black cotton soils of India, also known as Regur soils, are predominantly found in the Deccan Plateau region.
– These soils are formed by the weathering of basaltic lava rocks, which are the result of massive fissure volcanic eruptions that occurred during the formation of the Deccan Traps in the late Cretaceous period.
– Basalt is a type of extrusive igneous rock formed from the rapid cooling of magnesium-rich and iron-rich lava exposed at or very near the surface of a terrestrial planet or a moon.

– Black cotton soils are rich in clay minerals like montmorillonite, which causes them to swell when wet and shrink when dry, leading to characteristic cracks. They are known for their fertility and suitability for cotton cultivation, hence the name.
– Weathering of granite and schist typically produces red or yellow soils (e.g., in the Peninsular Plateau).

177. Consider the following statements : 1. Moringa (drumstick tree) is

Consider the following statements :

1. Moringa (drumstick tree) is a leguminous evergreen tree.
2. Tamarind tree is endemic to South Asia.
3. In India, most of the tamarind is collected as minor forest produce.
4. India exports tamarind and seeds of moringa.
5. Seeds of moringa and tamarind can be used in the production of biofuels.

Which of the statements given above are correct?

[amp_mcq option1=”1, 2, 4 and 5″ option2=”3, 4 and 5″ option3=”1, 3 and 4″ option4=”1, 2, 3 and 5″ correct=”option2″]

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UPSC IAS – 2021

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The correct answer is B) 3, 4 and 5.

– Statement 1 is incorrect. Moringa (Moringa oleifera) belongs to the family Moringaceae, not the Leguminosae (Fabaceae).
– Statement 2 is incorrect. The Tamarind tree (Tamarindus indica) is native to tropical Africa, although it is widely cultivated in South Asia.
– Statement 3 is likely considered correct in this context. Tamarind is listed as a Minor Forest Produce (MFP) in India, and significant quantities are collected from forests and non-cultivated areas, particularly benefiting tribal and rural populations. While commercial cultivation exists, collection as MFP is a notable source.
– Statement 4 is correct. India is a major producer and exporter of tamarind and various moringa products, including seeds, powder, and oil, due to their economic and nutritional value.
– Statement 5 is correct. Both moringa seeds (for oil) and tamarind seeds (for carbohydrates and oil) are being explored and used in the production of biofuels.

– Moringa is known as a “miracle tree” for its high nutritional value and various uses.
– Tamarind is a tropical fruit tree widely used for its pulp in culinary applications.
– The classification of produce as MFP varies by region and state in India.

178. With reference to the water on the planet Earth, consider the followin

With reference to the water on the planet Earth, consider the following statements :

1. The amount of water in the rivers and lakes is more than the amount of groundwater.
2. The amount of water in polar ice caps and glaciers is more than the amount of groundwater.

Which of the statements given above is/are correct?

[amp_mcq option1=”1 only” option2=”2 only” option3=”Both 1 and 2″ option4=”Neither 1 nor 2″ correct=”option2″]

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The correct answer is B) 2 only.

– Statement 1 is incorrect. The amount of groundwater on Earth is significantly greater than the amount of water in all rivers and lakes combined. Approximately 30% of the world’s freshwater is groundwater, while surface water bodies like rivers and lakes hold a much smaller fraction (less than 1%).
– Statement 2 is correct. The largest reservoir of freshwater is in polar ice caps and glaciers, which hold approximately 68.7% of the total freshwater. This amount is greater than the groundwater reservoir, which holds about 30.1% of freshwater.

– The vast majority (around 97.3%) of Earth’s water is saline water in oceans. Freshwater accounts for only about 2.7%, most of which is locked up in ice and groundwater.

179. The vegetation of savannah consists of grassland with scattered small

The vegetation of savannah consists of grassland with scattered small trees, but extensive areas have no trees. The forest development in such areas is generally kept in check by one or more or a combination of some conditions.
Which of the following are such conditions?

1. Burrowing animals and termites
2. Fire
3. Grazing herbivores
4. Seasonal rainfall
5. Soil properties

Select the correct answer using the code given below.

[amp_mcq option1=”1 and 2″ option2=”4 and 5″ option3=”2, 3 and 4″ option4=”1, 3 and 5″ correct=”option3″]

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The correct answer is C) 2, 3 and 4.

– Savannas are characterized by grasslands with scattered trees due to factors that limit dense forest growth.
– Fire (2) is a major factor, as seasonal dry periods make savannas prone to fires that kill young trees and favor fire-resistant grasses.
– Grazing herbivores (3) consume young trees and shrubs, preventing them from establishing and growing into mature trees.
– Seasonal rainfall (4), particularly the prolonged dry season, creates water stress that limits tree growth and increases fire frequency, contributing to the maintenance of the savanna structure.

– Burrowing animals and termites (1) can affect soil and vegetation locally but are not typically considered the primary factors controlling forest development across extensive savanna areas.
– Soil properties (5) can influence vegetation, but fire, grazing, and climate (seasonal rainfall patterns) are generally regarded as the dominant factors preventing savanna from transitioning into forest.

180. Which one of the following factors constitutes the best safeguard of l

Which one of the following factors constitutes the best safeguard of liberty in a liberal democracy?

[amp_mcq option1=”A committed judiciary” option2=”Centralization of powers” option3=”Elected government” option4=”Separation of powers” correct=”option4″]

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The correct answer is D) Separation of powers.

– In a liberal democracy, the principle of separation of powers ensures that governmental powers are divided among distinct branches (legislative, executive, and judicial), preventing the concentration of power in any single entity. This system of checks and balances limits the potential for arbitrary rule and protects individual liberties.

– A committed judiciary (A) is essential for upholding liberty, but it is a critical component *within* the framework of separation of powers.
– Centralization of powers (B) is generally detrimental to liberty, leading towards potential authoritarianism.
– An elected government (C) is fundamental to democracy, but without constitutional limits and separation of powers, even an elected body can infringe upon liberties (e.g., tyranny of the majority).
– Thus, separation of powers is considered the foundational principle that best safeguards liberty by distributing authority and establishing checks and balances.