UPSC 2020 Science and Technology Questions with Answers
14 previous year UPSC Prelims questions on Science and Technology in the UPSC 2020 Prelims. Choose an option to see the answer and explanation.
Explanations state facts as of the year each question was asked; words like “recently” refer to that year.
Showing 11–14 of 14 questions
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UPSC 2020Science and Technology · Miscellaneous
Q11. Which of the following statements are correct regarding the general difference between plant and animal cells? 1. Plant cells have cellulose cell walls whilst animal cells do not. 2. Plant cells do not have plasma membranes unlike animal cells which do. 3. Mature plant cell has one large vacuole whilst an animal cell has many small vacuoles. Select the correct answer using the code given below:
Explanation
Statement 1 is correct: Both plants and animals contain eukaryotic cells, their cell structures are quite similar. The plasma membrane, nucleus, cytoplasm, ribosomes, and mitochondria in general make up each eukaryotic cell. The plant cell differs significantly from other cells in that it has a hard cell wall surrounding it. While the cells of other species are surrounded by a cell wall, cellulose and proteins are present in plant cells.
Statement 2 is incorrect: Both plant and animal cells have a plasma membrane that surrounds the cytoplasm and regulates the movement of substances in and out of the cell. The plasma membrane is essential for maintaining homeostasis and facilitating communication between the cell and its environment in both plant and animal cells.
Statement 3 is correct: A mature plant cell typically contains a single, large central vacuole, which can occupy up to 90% of the cell’s volume. This vacuole stores water, nutrients, and waste products and helps maintain turgor pressure, providing structural support to the plant. Animal cells often have multiple small vacuoles scattered throughout the cytoplasm. These vacuoles perform similar storage and waste-management functions but are smaller and less prominent than those in plant cells. Animal Cell Plant Cell
UPSC 2020Science and Technology · Miscellaneous
Q12. In the context of recent advances in human reproductive technology. "Pronuclear Transfer" is used for
Explanation
Pronuclear transfer is an advanced reproductive technique primarily utilized to prevent the transmission of mitochondrial diseases from mother to offspring. Mitochondrial diseases are genetic disorders caused by mutations in mitochondrial DNA (mtDNA), which is inherited exclusively from the mother. These disorders can lead to severe health issues, affecting organs with high energy demands, such as the brain, heart, and muscles.
UPSC 2020Science and Technology · Miscellaneous
Q13. With reference to solar water pumps, consider the following statements: 1. Solar power can be used for running surface pumps and not for submersible pumps. 2. Solar power can be used for running centrifugal pumps and not the ones with piston. Which of the statements given above is/are correct?
Explanation
Statement 1 is incorrect: Solar power is capable of operating both surface and submersible pumps. Surface Pumps are installed above the water surface and are suitable for applications where water is drawn from shallow sources. They can be effectively powered by solar energy. Submersible pumps are designed to operate underwater. These pumps are ideal for deep wells or boreholes. Solar-powered submersible pumps are widely used for extracting water from significant depths.
Statement 2 is incorrect: Solar power can be utilized to run both centrifugal and piston (positive displacement) pumps. Centrifugal Pumps are commonly used in solar applications for higher flow rates with lower lift. They are efficient when adequate solar power is available. Piston Pumps also known as positive displacement pumps, piston pumps are suitable for applications requiring high lift with lower flow rates. Their ability to maintain efficiency under varying conditions makes them well-suited for solar-powered systems.
Exam tip:
Solar power is just a source of electricity. It can power any device that runs on electricity -- depending on how much power (wattage) you generate. Why would solar care about pump mechanism? It just supplies electricity. The motor and circuit handle the internal mechanics. Hence both statements are restrictive by saying "NOT"and hence likely false.
UPSC 2020Science and Technology · Miscellaneous
Q14. With reference to the current trends in the cultivation of sugarcane in India, consider the following statements: 1. A substantial saving in seed material is made when ‘bud chip settings’ are raised in a nursery and transplanted in the main field. 2. When direct planting of seeds is done, the germination percentage is better with single -budded setts as compared to setts with many buds. 3. If bad weather conditions prevail when seeds are directly planted, single - budded seeds have better survival as compared to large setts. 4. Sugarcane can be cultivated using settlings prepared from tissue culture. Which of the statements given above is/are correct?
Explanation
Tissue culture (TC) is the cultivation of plant cells, tissues, or organs on specially formulated nutrient media. Under the right conditions, an entire plant can be regenerated from a single cell. Commercial planting of sugarcane uses setts (cuttings that can form roots) at a rate of 6 to 8 tonnes per hectare, or around 10% of total production.
Statement 1 is correct: Due to its bulky attire and physical restrictions, the tissue culture method is becoming uneconomical. Planting excised axillary canestalk buds, sometimes referred to as budchips, would help reduce the mass and enhance the quality of the seed cane. After four to five weeks, healthy settlings are transplanted on a well-prepared field with a row spacing of 90 cm and a gap of 30 cm between each settling (small setts).
Statement 2 is incorrect: Due to moisture loss from the other cut end, the germination percentage of a single bud sett is extremely low. Numerous studies and trials demonstrate that the germination rate of 3 bud sets is higher than the setts having more or less than three buds. Additionally, even if the entire can stem is planted without being trimmed, only the top end will sprout, resulting in a poor germination percentage.
Statement 3 is incorrect: Under bad weather conditions, larger setts (multi-budded) generally have better survival rates compared to single-budded setts. This is because they store more nutrients and moisture, which helps them withstand adverse conditions better than single-budded setts.
Statement 4 is correct: The most crucial and labour-intensive step in sugarcane agriculture is planting. Supplying disease-free seed cane of current commercial types quickly is an innovative new technique, called tissue culture. It employs meristems to clone the mother plant. Tissue culture plants’ cane and sugar yields are comparable to those of plants grown using traditional methods.
Exam tip:
S2 and S3 seems counterintuitive. A sett with multiple buds has a higher chance that at least one will germi-nate. Single-budded setts are more vulnerable. Hence both are likely false. In bad weather, again, single buds are more fragile. Bigger setts might be physically more resilient and offer redundancy.
Answer key for these questions
Q
UPSC year
Correct answer
11
2020
(c) 1 and 3 only
12
2020
(d) prevention of mitochondrial diseases in offspring
13
2020
(d) Neither 1 nor 2
14
2020
(c) 1 and 4 only
Frequently asked questions
How many previous year UPSC questions are there on Science and Technology?
This page covers 14 previous year UPSC Prelims GS Paper-I questions on Science and Technology in the UPSC 2020 Prelims, asked from 1996 to 2025. Each has the correct answer and an explanation.
How should I use previous year UPSC questions for Prelims?
Attempt each question first, then open the answer and read the explanation for every option. Repeat by chapter, and track which statements UPSC reuses across years. Previous year questions show the exam pattern and difficulty level.
Which years are covered for Science and Technology?
Questions on Science and Technology in the UPSC 2020 Prelims are available for 30 years, from 1996 to 2025. Use the Year filter to practise a single paper.
