Miscellaneous: UPSC Previous Year Questions (Science and Technology)

Explanation

A drone, technologically, is an unmanned aircraft.

They are formally known as unmanned aerial vehicles (UAVs). A drone is essentially a flying robot that can be remotely piloted or can fly on its own using software-controlled flight plans in embedded systems in conjunction with onboard sensors and GPS.

Statement 1 is correct: Modern agriculture has increasingly adopted drones for the application of pesticides and fertilizers. These drones offer precision in spraying, ensuring uniform coverage and reducing the exposure of farmers to harmful chemicals. For instance, a study published in Springer highlights that drones equipped with advanced sensors and high-resolution cameras can distinguish between healthy and infested crops, allowing for targeted pesticide application.

Statement 2 is correct: Drones equipped with visual and thermal cameras are utilized in geological studies to inspect active volcano craters. They can safely approach hazardous areas, capturing high-resolution images and collecting gas samples. Researchers from the German Research Centre for Geosciences (GFZ) successfully employed drones to study the active Santa Maria volcano in Guatemala.

Statement 3 is correct: Marine biologists have innovated methods to collect biological samples from whales using drones. By flying drones through the spouts of whales, researchers can gather respiratory droplets containing DNA, hormones, and microorganisms without disturbing the animals. This technique was employed in the Ocean Alliance’s SnotBot program.

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

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.

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.

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.