S&T 2021

Question 1

Why is water known as the universal solvent?

Answer 1

It is dipolar in nature

Water can dissolve more compounds than any other solvent due to its polar nature, which creates hydrophobic and hydrophilic sides.

Question 2

What is the characteristic wavelength of light produced by sodium-vapor lamps?

Answer 2

Near 589 nm

Sodium-vapor lamps produce a warm yellow glow and their spectrum of visible light is almost monochromatic.

Question 3

What are the two varieties of sodium lamps?

Answer 3

Low pressure and high pressure

Low-pressure sodium lamps emit monochromatic yellow light, while high-pressure sodium lamps emit a broader spectrum.

Question 4

What is the average lifespan of high-pressure sodium lamps?

Answer 4

24,000 hours

High-pressure sodium lights maintain their luminance for most of their lifespan.

Question 5

What does LED stand for?

Answer 5

Light Emitting Diode

LEDs are semiconductor devices that emit light when an electric current passes through.

Question 6

What is a significant environmental advantage of LED lights over incandescent bulbs?

Answer 6

They do not contain mercury

LEDs have a lower environmental impact compared to traditional bulbs.

Question 7

What is ACE2 associated with?

Answer 7

Spread of viral diseases

ACE2 acts as a receptor for the SARS-CoV-2 virus, enabling its entry into human cells.

Question 8

BPA is a key component in the manufacture of which type of plastic?

Answer 8

Polycarbonate

BPA is commonly used in the production of polycarbonate plastics and epoxy resins.

Question 9

What is the primary use of low-density polyethylene (LDPE)?

Answer 9

Products like grocery bags and cling wrap

LDPE is flexible, transparent, and recyclable, making it popular for various packaging applications.

Question 10

What is the main characteristic of polycarbonate plastics?

Answer 10

Outstanding strength and impact resistance

Polycarbonate is lightweight and an excellent alternative to glass.

Question 11

What is polyethylene terephthalate (PET) primarily used for?

Answer 11

Manufacturing water bottles and packaging

PET is known for its strength, flexibility, and resistance to moisture.

Question 12

What type of polymer is polyvinyl chloride (PVC)?

Answer 12

Synthetic polymer of plastic

PVC is produced by polymerizing vinyl chloride and comes in rigid and flexible forms.

Question 13

What is a notable property of PVC?

Answer 13

Lightweight and sturdy

PVC is resistant to inorganic chemicals and is used in various construction applications.

Question 14

Fill in the blank: The angiotensin-converting enzyme 2 (ACE2) acts as a ______ for the virus that causes COVID-19.

Answer 14

receptor

ACE2 allows the SARS-CoV-2 virus to enter human cells.

Question 15

True or False: High-pressure sodium lamps have better color rendering than LED lamps.

Answer 15

False

High-pressure sodium lamps have poorer color rendering compared to LEDs.

Question 16

What is the environmental impact of bisphenol A (BPA)?

Answer 16

It can disrupt the endocrine system

BPA affects hormones and can lead to health issues in humans and wildlife.

Question 17

What is produced by the process of polymerization of the vinyl chloride monomer?

Answer 17

PVC

PVC stands for polyvinyl chloride, a widely used synthetic plastic polymer.

Question 18

What is the nature of PVC?

Answer 18

Amorphous

Being amorphous allows PVC to be easily combined with other chemicals and substances.

Question 19

List some qualities that can be imbued in PVC products through additives.

Answer 19

• Anti-mist
• Different colours
• Elasticity
• Fire retarding
• Flexibility
• Impact resistance
• Microbe prevention

Question 20

What are the properties of PVC?

Answer 20

• Lightweight
• Sturdy
• Abrasion-resistant
• Resistant to all inorganic chemicals
• Excellent insulation material
• High dielectric strength
• Vapour barrier capacity
• Corrosion-free

Question 21

What makes PVC suitable for outdoor applications?

Answer 21

It can withstand extreme climatic conditions, shock and is free from corrosion.

Question 22

How can PVC be made more flexible?

Answer 22

By adding plasticizers such as phthalate.

Question 23

True or False: PVC products are self-extinguishing due to high chlorine content.

Answer 23

True

Question 24

What is the primary use of plasticized PVC?

Answer 24

In flooring

PVC-U (unplasticized PVC) is used for making window frames.

Question 25

What are some applications of PVC?

Answer 25

* Sewage pipes * Insulation on electrical wires * Flooring for sterile environments * Various industries like building, electronics, automotive, medical, and packaging

Question 26

What is Triclosan?

Answer 26

An antibacterial and anti-fungal agent.

Question 27

Which products is Triclosan commonly found in?

Answer 27

* Antibacterial soaps * Body washes * Toothpaste * Some cosmetics

Question 28

What is a major concern regarding Triclosan?

Answer 28

It may contribute to making bacteria resistant to antibiotics.

Question 29

Define 'superbugs'.

Answer 29

Strains of bacteria, viruses, parasites, and fungi resistant to most common medications.

Question 30

What is Antimicrobial Resistance (AMR)?

Answer 30

The ability of a microorganism to stop an antimicrobial drug from working against it.

Question 31

What are some actions that may increase the spread of antimicrobial-resistant germs?

Answer 31

* Misusing antibiotics * Poor infection control practices * Living in unclean conditions * Mishandling food

Question 32

What is a light-year?

Answer 32

The distance light travels in one year.

Question 33

Why are astronomical distances measured in light-years?

Answer 33

Because the speed of light is always the same.

Question 34

What is the speed of light in miles per second?

Answer 34

186,000 miles per second.

Question 35

What is a DNA vaccine?

Answer 35

A type of vaccine that transfects a specific antigen-coding DNA sequence into cells to induce an immune response.

Question 36

List some advantages of DNA vaccines.

Answer 36

* Focused immune response * Cost-effective * Less risk for infection * Long-term persistence of immunogen

Question 37

What is mitochondrial disease?

Answer 37

A group of disorders caused by mitochondrial dysfunction.

Question 38

Who can pass on mitochondrial diseases?

Answer 38

Only from mother to child.

Question 39

What is mitochondrial replacement therapy (MRT)?

Answer 39

A reproductive technique that replaces a woman’s mitochondrial DNA with that of a donor.

Question 40

What are Bollgard I and Bollgard II technologies used for?

Answer 40

Developing genetically modified crop plants.

Question 41

What does Bollgard I cotton provide?

Answer 41

In-built protection against American Bollworm infestations.

Question 42

What is the primary benefit of genetically modified (GM) crops?

Answer 42

To give plants new properties such as increased yield or disease resistance.

Question 43

True or False: Bt cotton was the first and only transgenic crop approved by the GEAC.

Answer 43

True

Question 44

What are genetically modified crops?

Answer 44

Crops derived from plants whose genes are artificially modified to give them new properties such as increased yield and disease resistance. ## Footnote Examples include crops with herbicide tolerance, drought resistance, and improved nutritional value.

Question 45

What is golden rice?

Answer 45

A variety of GM rice enriched with Vitamin A, created by inserting genes from daffodils, maize, and a soil bacterium. ## Footnote Golden rice is intended to combat Vitamin A deficiency.

Question 46

Which GM crop was approved for commercial cultivation in India?

Answer 46

Bt cotton. ## Footnote GM Mustard has also been recommended for commercial use.

Question 47

What is one advantage of genetically modified seeds?

Answer 47

Increased yield. ## Footnote Farmers can produce more crops from the same plot of land.

Question 48

What is a disadvantage of genetically modified seeds?

Answer 48

Seeds can’t be replanted. ## Footnote GM seeds do not produce viable offspring, requiring farmers to repurchase seeds each planting season.

Question 49

What environmental concern is associated with GM crops?

Answer 49

They can decrease species diversity. ## Footnote Insect-resistant plants may harm non-target insect species.

Question 50

What ethical concern is raised regarding GM crops?

Answer 50

Violation of natural organisms’ intrinsic values by mixing species. ## Footnote There are also concerns about mixing animal genes in plants.

Question 51

What is Dhara Mustard Hybrid (DMH-11)?

Answer 51

An indigenously developed transgenic mustard that is herbicide tolerant. ## Footnote It contains two alien genes from a soil bacterium for breeding high-yielding hybrids.

Question 52

What is the significance of GM mustard in India?

Answer 52

It aims to make India self-reliant in oil production. ## Footnote India currently imports a significant amount of edible oil, costing billions in foreign exchange.

Question 53

Which organisms can be cultured in an artificial/synthetic medium?

Answer 53

Bacteria and fungi. ## Footnote Viruses require living host cells for replication and cannot be grown in synthetic media.

Question 54

True or False: Adenoviruses have single-stranded DNA genomes.

Answer 54

False. ## Footnote Adenoviruses have double-stranded DNA genomes.

Question 55

Which virus causes the common cold?

Answer 55

Adenovirus. ## Footnote AIDS is caused by a retrovirus.

Question 56

What is a retrovirus?

Answer 56

A type of virus that uses RNA as its genomic material and inserts a DNA copy of its RNA genome into a host cell. ## Footnote Retroviruses include HIV, which is classified as a retrovirus due to its use of reverse transcriptase.

Question 57

What is reverse transcription in the context of retroviruses?

Answer 57

The process of converting RNA into DNA using reverse transcriptase. ## Footnote This allows the viral RNA genome to integrate into the host cell's DNA.

Question 58

Fill in the blank: Retroviruses have _______ as their genomic material.

Answer 58

RNA.

Question 59

Fill in the blank: Only _______ viruses undergo reverse transcription.

Answer 59

RNA.