Daily Quiz: UPSC Prelims Marathon – October 25, 2018

Statement 1 is correct. Bioluminescence occurs through a chemical reaction that produces light energy within an organism’s body. For a reaction to occur, a species must contain luciferin, a molecule that, when it reacts with oxygen, produces light. There are different types of luciferin, which vary depending on the animal hosting the reaction. Many organisms also produce the catalyst luciferase, which helps to speed up the reaction.

The light emitted by a bioluminescent organism is produced by energy released from chemical reactions occurring inside (or ejected by) the organism.

Statement 2 is correct. Bioluminescence is found in many marine organisms: bacteria, algae, jellyfish, worms, crustaceans, seastars, fish, and sharks to name just a few. In some cases, animals take in bacteria or other bioluminescent creatures to gain the ability to light up. For example, the Hawaiian bobtail squid has a special light organ that is colonized by bioluminescent bacteria within hours of its birth.

All of the above events can produce gravitational waves.

Gravitational waves are ‘ripples’ in the fabric of space-time caused by some of the most violent and energetic processes in the Universe.

Einstein’s mathematics showed that massive accelerating objects (such as neutron stars or black holes orbiting each other) would disrupt space-time in such a way that ‘waves’ of distorted space would radiate from the source (like the movement of waves away from a stone thrown into a pond). Furthermore, these ripples would travel at the speed of light through the Universe, carrying with them information about their cataclysmic origins, as well as invaluable clues to the nature of gravity itself.

The strongest gravitational waves are produced by catastrophic events such as colliding black holes, the collapse of stellar cores (supernovae), coalescing neutron stars or white dwarf stars, the slightly wobbly rotation of neutron stars that are not perfect spheres, and the remnants of gravitational radiation created by the birth of the Universe itself.

Statement 1 is correct. The Hubble Space Telescope is a large telescope in space. NASA launched Hubble in 1990.

Statement 2 is correct. The mixture of gases that surround a planet is called its atmosphere. Earth’s atmosphere changes and blocks some of the light that comes from space. Hubble flies around, or orbits, high above Earth and its atmosphere. So, Hubble can see space better than telescopes on Earth can.

Statement 1 is incorrect. Only the cells of advanced organisms, known as eukaryotes, have a nucleus. Generally there is only one nucleus per cell, but there are exceptions, such as the cells of slime molds and the Siphonales group of algae. Simpler one-celled organisms (prokaryotes), like the bacteria and cyanobacteria, don’t have a nucleus.

In these organisms, all of the cell’s information and administrative functions are dispersed throughout the cytoplasm.

Statements 2 and 3 are correct. The nucleus is a highly specialized organelle that serves as the information processing and administrative center of the cell. This organelle has two major functions: it stores the cell’s hereditary material, or DNA, and it coordinates the cell’s activities, which include growth, intermediary metabolism, protein synthesis, and reproduction (cell division).

Statement 1 is incorrect. Excitonium is a condensate made up of excitons. Excitons are particles that are formed in a very strange quantum mechanical pairing. They are obtained by combining escaped electrons and “holes”.

This quirky quantum-mechanical pairing is possible because, in semiconductors, electrons on edge of one energy level in atom are able to jump into the next energy level when excited, leaving behind a “hole” in previous level. This hole acts like a positively charged particle, attracting the negatively charged electron that escaped.

Statement 2 is correct.Excitonium exhibits macroscopic quantum phenomena, like a superconductor and this findings holds great promise for unlocking further quantum mechanical mysteries. As a superconductor and superfluid, this material can be used to further existing technologies. These applications, especially those in practical technologies, are purely speculative at this point.

Exocrine glands are cellular sub-structures, organs, in a body that provide a system to secrete substances out and external to the body.

They are distinct from the other type of gland, endocrine, in that exocrine gland secretions end up external to the body, while endocrine secretions go into the bloodstream/internal. Exocrine glands secrete their substances through a ductal system.

Depending on the exocrine gland, they can function to regulate body temperature, lubricate, nurture newborns (lactation), aid in digestion, and aid in reproduction.

Examples of Exocrine Glands (and Secreted Product)

Lacrimal gland (Tear ducts and glands near each eye)

Mammary gland (Breast milk)

Eccrine sweat glands (Perspiration or salty water release)

Salivary glands (Saliva consisting of fluid with digestive enzymes)

Pancreas (Pancreatic juice with digestive enzymes into the stomach)

Liver (Bile, green-brown fluid that contains salts and digestion substances)

Note: Examples 5 and 6 are also considered endocrine glands because they also secrete other substances into the bloodstream

Concave mirror is used as a Shaving mirror.

The passenger-side mirror on a car is typically a convex mirror.

These mirrors are often found in the hallways of various buildings (commonly known as “hallway safety mirrors”), including hospitals, hotels, schools, stores, and apartment buildings.

They are usually mounted on a wall or ceiling where hallways intersect each other, or where they make sharp turns.

Convex mirrors are used in some automated teller machines as a simple and handy security feature, allowing the users to see what is happening behind them.

Convex mirrors make everything seem smaller but cover a larger area of surveillance.