Prelims Daily MCQs - Science and Technology (27 April)

1. Consider the following statements regarding the Rare Earth Minerals:

  1. India has a monopoly over rare earth minerals followed by china.
  2. Rare earth minerals are very crucial for India in order to reduce the energy burden and manufacturing of advanced defence equipment.
  3. Recently established Minerals Security Partnership (MSP) is an initiative led by India to secure supply chains of critical minerals, aimed at reducing dependency on China.

Select the correct answer using the code given below:

a) 3 only

b) 2 only

c) 1 and 3 only

d) None of the above

Ans: b

Exp: Statement 1 is incorrect: The 17 rare earth elements (REE). REEs are classified as light RE elements (LREE) and heavy RE elements (HREE).India has the fifth-largest reserves of rare earth minerals in the world. Due to the radioactivity of monazite sands, Indian Rare Earths Ltd under the Department of Atomic Energy is the sole producer of rare earth compounds. Globally, China has a monopoly over rare earth, after the USA's retreat in this industry due to high environmental and health concerns.

Statement 2 is correct: Rare earth minerals are very crucial for India in order to reduce the energy burden. It is an important component in the manufacture of hybrid vehicles, fuel cells and LEDs. According to India's ambitious plan, 80 % of the country’s two- and three wheeler fleet, 40% of buses, and 30 to 70 % of cars will be EVs by 2030. It is indispensable in the manufacture of advanced defence equipment and Essential for purifying the rivers flowing across the country. It is used in the manufacture of electronic gadgets which would help in our Digital India programme. Minerals like Cobalt, Nickel, and Lithium are required for batteries used in electric vehicles.

Statement 3 is incorrect: The United States and key partner countries have announced the establishment of the Minerals Security Partnership (MSP), a new initiative to bolster critical mineral supply chains.It is an alternative to China to ensure key industrial supplies. India is not part of this arrangement.The US and 10 countries including Australia, France, Canada, Finland, Germany, Japan, South Korea, Sweden, the United Kingdom, and the European Commission have come together to form the MSP. The goal of the MSP is to ensure that critical minerals are produced, processed, and recycled in a manner that supports the ability of countries to realise the full economic development benefit of their geological endowments. The alliance is seen as an alternative to China, which has created processing infrastructure in rare earth minerals and has acquired mines in Africa for elements such as Cobalt.

2. Consider the following statements regarding Gene modulation:

  1. Gene modulation refers to the process of permanently altering gene expression levels making heritable changes to the underlying cellular DNA.
  2. Unlike genetic modification no outside gene is used in gene modulation as it only seeks to alter the expression of an endogenous gene.

Select the correct answer using the code given below:

a) 1 only

b) 2 only

c) Both 1 and 2

d) Neither 1 nor 2

Ans: d

S1: Gene modulation refers to the process of temporarily altering gene expression levels without making heritable changes to the underlying cellular DNA.

S2: In contrast, genetic modification involves the introduction of foreign genetic material into an organism's genome. Therefore, statement 2 is incorrect as gene modulation can involve the alteration of endogenous genes, but it does not exclude the possibility of introducing outside genes.

3. With reference to Measles, consider the following statements:

  1. It is a highly contagious bacterial disease.
  2. It can spread via droplets from the nose, mouth or throat of an infected person.
  3. There is no specific treatment for measles.

Select the correct answer using the code given below:

a) 1 only

b) 2 and 3 only

c) 3 only

d) 1, 2 and 3

Ans: b

Exp: Statement 1 is incorrect: Measles is a highly contagious viral disease caused by Rubella virus, a member of the paramyxovirus family. Measles symptoms do not show for 10 to 14 days after exposure. A rash on the body is the most typical sign of measles.

Statement 2 is correct: It is spread by droplets from an infected person's nose, throat, or mouth. It is an important cause of death among young children. Though the vaccine for measles was introduced in 1963, the number of deaths is high. Measles, if not treated effectively, can lead to long-term problems such as pneumonia and encephalitis.

Statement 3 is correct: There is no specific treatment for measles, nor is there antiviral therapy. For prevention, necessary precautions should be taken like children should be immunised within the first 12 months of birth. Further MMR (Mumps, Measles, and Rubella) is available to protect against the disease.

4. Consider the following as the benefits of using “biodiesel”:

  1. It is made from renewable sources and can be prepared locally.
  2. Increases engine performance It has excellent lubricity.
  3. Increased safety in storage and transport.
  4. Reduction of greenhouse gases.

Select the correct answer using the code given below.

a) 1 and 3

b) 1,2 and 4

c) 2 and 3

d) 1, 2, 3 and 4

Ans: d

Exp: Bio-diesel is an eco-friendly, alternative diesel fuel prepared from domestic renewable resources ie. vegetable oils (edible or non- edible oil) and animal fats. These natural oils and fats are primarily made up of triglycerides. These triglycerides when reacted chemically with lower alcohols in presence of a catalyst result in fatty acid esters. These esters show striking similarity to petroleum derived diesel and are called "Biodiesel". As India is deficient in edible oils, non-edible oil may be material of choice for producing biodiesel. Examples are Jatropha curcas, Pongamia, Karanja, etc.

The benefits of using biodiesel are as follows:

It reduces vehicle emission which makes it eco friendly. It is made from renewable sources and can be prepared locally. Increases engine performance because it has higher cetane numbers as compared to petro diesel. It has excellent lubricity. Increased safety in storage and transport because the fuel is nontoxic and biodegradable (Storage, high flash point)  Production of bio diesel in India will reduce dependence on foreign suppliers, thus helpful in price stability. Reduction of greenhouse gases at least by 3.3 kg CO2 equivalent per kg of biodiesel.

5.  Consider the following sentences:

  1. Crispr Cas9 technology can be used to modify certain sections of the DNA apart from repairing the damaged DNA.
  2. Cas9 acts as a molecular scissor to cut DNA at specific locations.
  3. Cas9 enzymes cannot function under very low temperatures.

Select the correct answer using the code given below:

a) 1 and 3 only

b) 1 and 2 only

c) 2 and 3 only

d) 1, 2 and 3

Ans: b

Exp: CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats.

Statement 2 is correct: The CRISPR-Cas9 system is made up of two essential molecules that induce mutations into the DNA. (i) Cas9- An enzyme that functions as a pair of "molecular scissors," allowing it to cut the two strands of DNA at a specified point in the genome. (ii) Guide RNA (gRNA)- That is intended to discover and attach to a certain sequence of DNA.

Statement 1 is correct: The Crispr Cas9 technology can be used for a variety of applications: edit parts of the genome by removing, adding or altering sections of the DNA sequence. It can also identify damaged parts of DNA and can be repaired. Further, it can be used in fundamental disease research, drug screening, and therapy development, rapid diagnostics, in-vivo editing and correction of heritable conditions.

Statement 3 is incorrect: Recently, Indian scientists have, for the first time, demonstrated that Cas9 enzyme can be used to bind to and cut the target DNA at very low temperatures.

6. Cost of 4 pens, 6 notebooks and 9 files is Rs. 305. Cost of 3 pens, 4 notebooks and 2 files is Rs. 145. What is the cost (in Rs) of 5 pens, 8 notebooks and 16 files?

a) 415

b) 440

c) 465

d) Cannot be determined.

Ans: c


Let the price of one pen be Rs. P, one notebook is Rs. N and one file be Rs. F

According to the problem statement

⇒ 4P + 6N + 9F = 305     ---- (i)

⇒ 3P + 4N + 2F = 145     ---- (ii)

Now 2 × (i) – (ii)

⇒ (8 – 3)P + (12 – 4)N + (18 – 2)F = 5P + 8N + 16F = 2 × 305 – 145 = 465

∴ The cost of 5 pens, 8 notebooks and 16 files is Rs. 465

7. Sonam borrowed a sum of money and returned it in two equal annual installments of Rs. 5,547 each. If the rate of interest was 7.5% per annum compounded yearly, then the total interest paid by her was :

a) 1124

b) 1134

c) 1144

d) 1154

Ans: b


Two equal annual installments = Rs. 5,547 each, the rate of interest(R) was 7.5% compounded yearly

P = [(Installment)/(1 + R/100)1  + (Installment)/(1+R/100)2 ]

(1 + R/100) = (1+15/200) = 215/200 = 43/40

⇒ P = [5547/(43/40)1 + 5547/(43/40)2 ]

⇒ P = 5547(40/43 + 1600/1849)

⇒ P = 5547(3320/1849)

⇒ P = Rs. 9960

⇒ Total Installment = 5547 × 2 = Rs. 11094

⇒ Total Interest = Rs(11094 - 9960)

⇒ Rs. 1134∴ Total interest is  Rs. 1134

Cover the entire CSAT syllabus in 70 hours.

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