Daily Quiz 21 April 2024

Answer: B
Explanation:
● Statement 1 is not correct: India is the second largest producer of silk and also the largest consumer of silk in the world. In India, mulberry silk is produced mainly in the states of Karnataka, Andhra Pradesh, Tamil Nadu, Jammu & Kashmir and West Bengal, while the non-mulberry silks are produced in Jharkhand, Chattisgarh, Orissa and north-eastern states.
● Statement 2 is correct: Mulberry silk comes from silkworms that eat only mulberry leaves. It is soft, smooth, and shiny with a bright glow, making it perfect for luxury sarees and high-end fabrics. 92% of the country’s total raw silk production comes from mulberry.
● Statement 3 is correct: Non-mulberry silk (also known as Vanya silk) comes from wild silkworms that feed on leaves from trees like oak, castor and arjun. This silk has a natural, earthy feel with less shine but is strong, durable, and eco-friendly.

Answer: A

Explanation:

• Recently, Defence Research and Development Organisation (DRDO) successfully conducted the Release Trials of Long-Range Glide Bomb (LRGB) ‘Gaurav’.
• Option A is correct: Long-range glide bombs, sometimes called standoff glide munitions, are unpowered or minimally powered precision-guided weapons that rely on aerodynamic lift to travel extended distances after being released from an aircraft.
• Unlike traditional free-fall bombs, glide bombs have wings or fins that allow them to glide toward their target, often covering ranges from tens to hundreds of kilometers.
• They typically incorporate advanced guidance systems—such as GPS, inertial navigation, or laser homing—to ensure accuracy, even against moving or heavily defended targets.
• So, Both Statement-I and Statement-II are correct and Statement-II explains Statement-I.

Answer: C

Explanation:

• Statements 1, 2 and 3 are correct: Vitamin D (also referred to as calciferol) is a fat-soluble vitamin that is naturally present in a few foods, added to others, and available as a dietary supplement. It is also produced endogenously when ultraviolet (UV) rays from sunlight strike the skin and trigger vitamin D synthesis.
• Vitamin D obtained from sun exposure, foods, and supplements is biologically inert and must undergo two hydroxylations in the body for activation. The first hydroxylation, which occurs in the liver, converts vitamin D to 25-hydroxyvitamin D [25(OH)D], also known as calcidiol. The second hydroxylation occurs primarily in the kidney and forms the physiologically active 1,25-dihydroxyvitamin D [1,25(OH)2D], also known as calcitriol.

Vitamin D promotes calcium absorption in the gut and maintains adequate serum calcium and phosphate concentrations to enable normal bone mineralization and to prevent hypocalcemic tetany (involuntary contraction of muscles, leading to cramps and spasms). It is also needed for bone growth and bone remodeling by osteoblasts and osteoclasts [1-3]. Without sufficient vitamin D, bones can become thin, brittle, or misshapen. Vitamin D sufficiency prevents rickets in children and osteomalacia in adults. Together with calcium, vitamin D also helps protect older adults from osteoporosis.

Answer: C

Explanation:

• Statement 1 is correct: Bioluminescence is a type of chemiluminescence occurring inside living organisms and produces “cold light” (less than 20% heat).
• Statement 2 is not correct: Although most bioluminescent organisms are marine, some are terrestrial (e.g., fireflies, fungi); freshwater bioluminescent organisms are rare but not entirely absent.
• Statement 3 is correct: The chemical reaction that results in bioluminescence requires two unique chemicals: luciferin and either luciferase or photoprotein. Luciferin is the compound that actually produces light. In a chemical reaction, luciferin is called the substrate. The bioluminescent color (yellow in fireflies, greenish in lanternfish) is a result of the arrangement of luciferin molecules.
  • Some bioluminescent organisms produce (synthesize) luciferin on their own. Dinoflagellates, for instance, bioluminesce in a bluish-green color. Bioluminescent dinoflagellates are a type of plankton—tiny marine organisms that can sometimes cause the surface of the ocean to sparkle at night.
  • Some bioluminescent organisms do not synthesize luciferin. Instead, they absorb it through other organisms, either as food or in a symbiotic relationship. Some species of midshipman fish, for instance, obtain luciferin through the “seed shrimp” they consume. Many marine animals, such as squid, house bioluminescent bacteria in their light organs. The bacteria and squid have a symbiotic relationship.
  • Luciferase is an enzyme. An enzyme is a chemical (called a catalyst) that interacts with a substrate to affect the rate of a chemical reaction. The interaction of the luciferase with oxidized (oxygen-added) luciferin creates a byproduct, called oxyluciferin. More importantly, the chemical reaction creates light. Bioluminescent dinoflagellates produce light using a luciferin-luciferase reaction. The luciferase found in dinoflagellates is related to the green chemical chlorophyll found in plants.
• Statement 4 is correct: Kavaru’ or bioluminescence, the environmental phenomenon that gives the waters an electric blue backlight in Kochi, Kerala.

Answer: A

Explanation:

Option A is correct: China has unveiled the “Three Gorges Antarctic Eye,” a 3.2-metre aperture radio/millimetre-wave telescope, at a scientific research station in Antarctica. The “Three Gorges Antarctic Eye” has officially begun scientific observations of the Milky Way’s neutral hydrogen and ammonia molecular spectral lines, providing vital data to help unravel the dynamics of interstellar gas and the processes of star formation.