[Solution] – Friday Science Quiz #5

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[Solution]

Q.1) Consider the following pairs:
Vitamin Deficiency :        Disease

1. Vitamin C       :         Scurvy
2. Vitamin D       :         Rickets
3. Vitamin E       :         Night blindness

Which of the pairs given above is/are correctly matched?
a) 1 and 2 only
b) 3 only
c) 1, 2 and 3
d) None

Ans-[A]
Explanation – Nightblindness is caused by deficiency of vitamin A.
See the following link and learn the concepts very thoroughly.

Q.2) There is some concern regarding the nano-particles of some chemical elements that are used by the industry in the manufacture of various products. Why?

1. They can accumulate in the environment, and contaminate water and soil.
2. They can enter the food chains.
3. They can trigger the production of free radicals.

Select the correct answer using the code given below.
a) 1 and 2 only
b) 3 only
c) 1 and 3 only
d) 1, 2 and 3

Ans-[D]
Explanation- All statements are correct.

A nanoparticle (or nanopowder or nanocluster or nanocrystal) is a microscopic particle with at least one dimension less than 100 nm. Nanoparticle research is currently an area of intense scientific research, due to a wide variety of potential applications in biomedical, optical, and electronic fields.

Nanoparticles can easily contaminate the environment. They may be directly toxic to microbes, plants, and animals. Silver nanoparticles, for instance (though they are not toxic to humans), dissolve in water and release silver ions which are antibacterial. If silver nanoparticles are released into the environment, these types of concentrated silver ion releases could devastate local bacterial populations, with drastic consequences for the affected ecosystems. In this way, it can also enter into the food chain if some bacteria like this infects the food. There are other ways too but nanoparticles can enter the food chains.

Free radicals are an uncharged molecule typically highly reactive and short-lived, having an unpaired valency electron. Nanoparticles are capable of making free radicals. For example, at nanoscale these particles can easily enter inside the cells and cause biochemical changes via formation of free radicals. In human cells also they enter like this. Free radicals in biochemical reaction of humans have been linked with the Alzheimer’s and Parkinson’s diseases.

Q.3)  What is the difference between a CFL and an LED lamp?

1. To produce light, a CFL uses mercury vapour and phosphor while an LED lamp uses semi-conductor material.
2. The average life span of a CFL is much longer than that of an LED lamp.
3. A CFL is less energy-efficient as compared to an LED lamp.

Which of the statements given above is/are correct ?
a) 1 only.
b) 2 and 3 only.
c) 1 and 3 only.
d) 1, 2, and 3.

Ans- [C]
Explanation– Statement 1 is correct .CFLs, like all fluorescent lamps, contain mercury  as vapor inside the glass tubing. Most CFLs contain 3–5 mg per bulb, with the bulbs labeled “eco-friendly” containing as little as 1 mg.

Statement 2 is wrong as life of LED bulbs is upto 60-70 thousand hours and of CFL is 20-30 thousand hours

Statement 3 is correct. CFL are very much efficient than as compared to LED bulbs. This is one of the reason that government has started distributing LEDs in subsidised rates to phase out CFLs and bulbs.

Q.4) Which one of the following is the process involved in photosynthesis?
a) Potential energy is released to form free energy
b) Free energy is converted into potential energy and stored
c) Food is oxidized to release carbon dioxide and water
d) Oxygen is taken, and carbon dioxide and water vapour are given out

Ans-[B]
Explanation – The energy that drives photosynthesis originates in the center of the sun, where mass is converted to heat by the fusion of hydrogen. Over time, the heat energy reaches the sun’s surface, where some of it is converted to light by black body radiation that reaches the earth. A small fraction of the visible light incident on the earth is absorbed by plants. Through a series of energy transducing reactions, photosynthetic organisms are able to transform light energy into chemical free energy in a stable form that can last for hundreds of millions of years (e.g., fossil fuels). Statement B is thus correct.

Q.5) Other than resistance to pests, what are the prospects for which genetically engineered plants have been created?

1. To enable them to withstand drought
2. To increase the nutritive value of the produce
3. To enable them to grow and do photosynthesis in spaceships and space stations
4. To increase their shelf life

Select the correct answer using the codes given below:
a) 1 and 2 Only
b) 3 and 4 Only
c) 1, 2 and 4 Only
d) 1, 2, 3 and 4

Ans-[C]
Explanation- Genetically engineered plants involves insertion of some outside gene to insert some desirable property in the genome of the plant. This technique have been produced to do mainly statement 1,2 and 4. Statement 3 is wrong. There are experiments growing on to make plant grow in zero gravity. This is not the application yet of GMO. You can read about this growth of plant experiment here

Q.6) Recombinant DNA technology (Genetic Engineering) allows genes to be transferred

1. across different species of plants
2. from animals to plants
3. from microorganisms to higher organisms

Select the correct answer using the codes given below.
a) 1 only
b) 2 and 3 only
c) 1 and 3 only
d) 1, 2 and 3

Ans-[D]
Explanation – Recombinant DNA (rDNA) technology involves  laboratory methods of genetic recombination to bring together genetic material from multiple sources, creating sequences that would not otherwise be found in the genome. Thus it allows genes to transfer genes across all these organisms.

Q.7 Which one of the following sets of elements was primarily responsible for the origin of life on the Earth?
a) Hydrogen, Oxygen, Sodium
b) Carbon, Hydrogen, Nitrogen
c) Oxygen, Calcium, Phosphorus
d) Carbon, Hydrogen, Potassium

Ans-[B]
Explanation- Origin of the life depends upon 6 elements-carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus.

Q.8) Due to improper / indiscriminate disposal of old and used computers or their parts, which of the following are released into the environment as e-waste?

1. Beryllium
2. Cadmium
3. Chromium
4. Heptachlor
5. Mercury
6. Lead
7. Plutonium

Select the correct answer using the codes given below.
a) 1, 3, 4, 6 and 7 only
b) 1, 2, 3, 5 and 6 only
c) 2, 4, 5 and 7 only
d) 1, 2, 3, 4, 5, 6 and 7

Ans-[B]
Explanation- Heptachlor is an organochlorine compound that was once used as an insecticide. Plutonium is a radioactive material used in the nuclear reactors and bombs. Leaving these two all other are commonly used elements in the electronic circuits of computers.

Q.9) Consider the following phenomena:

1. Size of the sun at dusk
2. Colour of the sun at dawn
3. Moon being visible at dawn
4. Twinkle of stars in the sky
5. Polestar being visible in the sky

Which of the above are optical illusions?
a) 1, 2 and 3
b) 3, 4 and 5
c) 1, 2 and 4
d) 2, 3 and 5

Ans-[C]
Explanation– An optical illusion also called a visual illusion is characterized by visually perceived images that differ from object than reality. The information gathered by the eye is processed in the brain to give a perception that does not tally with a physical measurement of the stimulus source. Moon being visible in dawn and polestar being visible in sky are not any illusion. Size of the sun which appears big, color of the sun at dawn and twinkle of stars in the sky are not actual phenomenon but happens due to various factors such as refraction, different density of the air layers etc.