Science and Technology (Part-II)

Total Questions: 50

11. Microbial fuel cells are considered a source of sustainable energy. Why? [2011-1]

1. They use living organisms as catalysts to generate electricity from certain substrates.

2. They use a variety of inorganic materials as substrates.

3. They can be installed in waste water treatment plants to cleanse water and produce electricity.

Which of the following statements given above is/ are correct?

Correct Answer: (d) 1, 2 and 3
Solution:Atypical microbial fuel cell consists of anode and cathode compartments separated by a cation positively charged ion specific membrane. In the anode compartment fuel is oxidized by microorganisms generating electrons and protons. Electrons are transferred to the cathode compartment through an external electric circuit while protons are transferred to the cathode compartment through the membrane. Electrons and protons are consumed in the cathode compartment combining with oxygen to form water.

12. With reference to 'stem cells', frequently in the news, which of the following statements is/are correct? [2012-1]

1. Stem cells can be derived from mammals only.

2. Stem cells can be used for screening new drugs.

3. Stem cells can be used for medical therapies.

Select the correct answer using the codes given below :

Correct Answer: (b) 2 and 3 only
Solution:Stem cells can be used for medical therapies also can be used for screening new drugs.
About Stem Cells:
  • These are cells with the potential to develop into many different types of cells in the body.
  • Under the right conditions in the body or a laboratory, stem cells divide to form more cells called daughter cells.
  • These daughter cells become either new stem cells or specialized cells (differentiation) with a more specific function, such as blood cells, brain cells, heart muscle cells or bone cells.
  • No other cell in the body has the natural ability to generate new cell types.
  • They serve as a repair system for the body.
  • Stem cells are present inside different types of tissue. Scientists have found stem cells in tissues, including the brain, bone marrow, blood, and blood vessels, etc.

13. What are the reasons for the people's resistance to the introduction of Bt brinjal in India? [2012-1]

1. Bt brinjal has been created by inserting a gene from a soil fungus into its genome.

2. The seeds of Bt brinjal are terminator seeds and therefore, the farmers have to buy the seeds before every season from the seed companies.

3. There is an apprehension that the consumption of Bt brinjal may have adverse impact on health.

4. There is some concern that the introduction of Bt brinjal may have adverse effect on the biodiversity.

Select the correct answer using the codes given below:

Correct Answer: (c) 3 and 4 only
Solution:Bt Brinjal is created by inserting the Cry 1 Ac gene from the soil bacterium bacillus thuringiensis into Brinja. Seeds from Bt brinjal open-pollinated varieties will be free for farmers to save and replant as they wish. They have not terminated seeds.
Concerns related to Bt Brinjal
  • Risk to human health: The consumption ofBt Brinjal is harmful to human health because it contains antibiotic markers.
  • It produces a protein in vegetable cells that causes antibiotic resistance, leading to the ineffectiveness of medicines.
  • Toxicity studies done by Mahyco show that consuming genetically modified brinjal on a regular basis can cause immunological, liver, and reproductive issues.
  • Issues of Safety Test: The plant family Solanaceaeto, to which brinjal belongs, is problematic because it contains several natural toxins that can resurface when metabolism is disturbed. It is criticized that the testing is not specific or stringent enough
    to detect toxins.
  • Loss of biodiversity: There are about 2000 varieties grown across India. Transgene transfer to local and hybrid brinjal varieties will effectively eliminate brinjal diversity,
  • Economic Impact: While doing agronomic studies, Bt brinjal has not been compared with best agricultural practices like non-pesticide management.
  • The majority of the farmers in India are small and marginal farmers, so the possibility of maintaining isolation distances is nonexistent.

14. Other than resistance to pests, what are the prospects for which genetically engineered plants have been created? [2012-1]

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:

Correct Answer: (c) 1, 2 and 4 only
Solution:Except 3rd, all the statements are correct.
GM Crops have several advantages which include
  • Better than conventional breeding: Genetic Modification is one of the best methods to develop pest-resistant crops such as Bt crops. It is faster to introduce the required traits than by the conventional breeding process. It enables genetic modification in such a way that may not have been possible through conventional breeding methods, such as the introduction of a gene from different organisms.
  • Pest resistance: The Bt genes are toxic to many pests, thus eliminating the need for externally applied chemicals. This reduces the need for environmentally damaging pesticides. This increases yield, saves farmers' money and reduces environmental pollution.
  • Virus resistance: Virus-resistant traits can be introduced into vulnerable plants that lack natural resistance. This increases the productivity of crops.
  • Drought-resistant plants: Plants can be modified to express tolerance to drought hence, it reduces the use of groundwater.
  • Herbicide tolerance: GM crops are engineered to be resistant to specific herbicides that can be used to control weeds. It reduces soil erosion because the weed removal process such as ploughing and tilling is not required for these crops. This also reduces soil, water and air pollution.
  • Sustainable agricultural practice: Genetically modified crops enable farmers to use more sustainable agricultural practices, such as no-till farming, which keeps the carbon within the soil rather than in the atmosphere.
  • Enhanced nutritional value: Food crops can be modified genetically to increase their nutritional value. This can be beneficial to health, and increase food security around the world.

15. Mycorrhizal biotechnology has been used in rehabilitating degraded sites because mycorrhiza enables the plants to : [2013-1]

1.  resist drought and increase absorptive area

2. tolerate extremes of pH

3. resist disease infestation

Select the correct answer using the codes given below.

Correct Answer: (d) 1, 2 & 3
Solution:Mycorrhizal associations play vital role in plant nutrition. They greatly increase the efficiency of nutrient and water uptake; enhance resistance to pathogens, and buffer plant species against several environmental stresses and drought resistance. Mycorrhizal also improve plant growth and survival in soils contaminated by heavy metals.

16. Recombinant DNA technology (Genetic Engineering) allows genes to be transferred : [2013-1]

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:

Correct Answer: (d) 1, 2 and 3
Solution:Recombinant DNA are DNA sequences, which result from bringing genetic material form different sources. The genes can be transferred between any species, that is across different species of plants, from animals to plants and from microorganisms to higher organisms.

17. There is some concern regarding the nanoparticles of some chemical elements that are used by the industry in the manufacture of various products. Why? [2014-1]

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:

Correct Answer: (d) 1, 2 and 3
Solution:All are correct. Inhaled nanoparticles may represent a potential health risk. Aerosols in workplace environments may be derived from a wide variety of sources, depending on the type of activity and processes taking place.

In the presence of larger microparticles, as with the wide size distribution in aerosols such as smoke, the highly diffusive character of nanoparticles may lead to faster agglomeration or impaction on the larger particles. Furthermore, many particles, including metallic particles, are highly pyrophoric and there is a considerable risk of dust explosions.

18. With reference to the use of nano-technology in health sector, which of the following statements is/are correct? [2015-1]

1. Targeted drug delivery is made possible by nanotechnology.

2. Nanotechnology can largely contribute to gene therapy.

Select the correct answer using the code given below.

Correct Answer: (c) Both 1 and 2
Solution:Targeted drug delivery is made possible by nanotechnology. Medical nanotechnology can largely contribute to genetic therapy and improvement. Diseases can be easily treated if approached at the genetic level. So instead of treating diseases based on the symptoms, nanotechnology will help medical practitioners treat the problem by looking at the root cause.

19. The Genetic Engineering Appraisal Committee is constituted under the : [2015-1]

Correct Answer: (c) Environment (Protection) Act, 1986
Solution:

About Genetic Engineering Appraisal Committee (GEAC):

  • It is the statutory committee constituted under the “Rules for the Manufacture, Use/Import/Export and Storage of Hazardous Micro Organisms/Genetically Engineered Organisms or Cells (Rules, 1989)” framed under the Environment (Protection) Act, 1986.
  • It was earlier called the Genetic Engineering Approval Committee, which was changed to Genetic Engineering Appraisal Committee in the year 2010.
  • It functions in the Ministry of Environment, Forest, and Climate Change (MoEF&CC).

The functions of GEAC as prescribed in the Rules 1989 are as follows:

  • To appraise activities involving large-scale use of hazardous microorganisms and recombinants in research and industrial production from the environmental angle.
  • To appraise proposals relating to the release of genetically engineered organisms and products into the environment, including experimental field trials.
  • The committee or any persons authorized by it has powers to take punitive action under the Environment Protection Act.
  • It keeps a check on the use, import, and export of genetically modified (GM) organisms and crops.
  • Clearance of GEAC is mandatory for the environmental releaseof GM crops.

20. With reference to 'fuel cells' in which hydrogen-rich fuel and oxygen are used to generate electricity, consider the following statements: [2015-1]

1. If pure hydrogen is used as a fuel, the fuel cell emits heat and water as by- products.

2. Fuel cells can be used for powering buildings and not for small devices like laptop computers.

3. Fuel cells produce electricity in the form of Alternating Current (AC)

Which of the statements given above is/are correct?

Correct Answer: (a) 1 only
Solution:A fuel cell is a device that converts chemical energy into electrical energy by using hydrogen gas and oxygen gas. The products of this reaction are water electricity and heat.
  • Ballard fuel cell modules power trucks, buses, and trams in Europe and the US.
  • Small methanol fuel cells charge mobiles and laptops during natural disasters when grid power is disrupted.
  • A 1.4 MW phosphoric acid fuel cell system powered by biogas provides electricity and thermal energy to the ONGC Energy Center in Uran, Maharashtra.
  • Indian Railways is testing fuel cell-battery hybrid systems to power coaches and reduce diesel consumption.
  • Kerala Startup Mission has deployed micro-PEMfuel cell systems that provide power for telecom towers and weather stations in remote areas.
  • DRDO is developing portable methanol-based fuel cells to charge military batteries and equipment in the field.