'Wolbachia method' is sometimes talked about with reference to which one of the following?
- A.Controlling the viral diseases spread by mosquitoes
- B.Converting crop residues into packing material
- C.Producing biodegradable plastics
- D.Producing biochar from thermo-chemical conversion of biomass
Correct answer
Explanation
The correct answer is A, Controlling the viral diseases spread by mosquitoes. The method uses a natural bacterium to stop mosquitoes from passing on viruses.
Wolbachia is a common bacterium that lives inside the cells of many insects. When scientists introduce it into Aedes aegypti mosquitoes, which do not carry it naturally, the bacterium competes with viruses such as dengue, Zika and chikungunya and makes it much harder for the mosquito to transmit them. The mosquitoes carrying Wolbachia are released to breed with the wild population, and because the bacterium passes from mother to offspring, it spreads through the local mosquito population on its own. Field releases in several countries have cut dengue cases sharply, and ICMR has studied it in India.
B is wrong because turning crop residue into packing material is a paddy-straw use, not a bacterial mosquito method. C is wrong because biodegradable plastics come from polymers such as polylactic acid. D is wrong because biochar is made by pyrolysis of biomass.
Exam tip: Wolbachia + Aedes aegypti = fewer dengue, Zika and chikungunya infections.
Practice Questions
View allThe fact that the planets move around the Sun, not in circles but in ellipses, was first demonstrated by
- A.Galileo
- B.Martin Luther
- C.Johannes Kepler
- D.Copernicus
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In 1609 Kepler showed that the planets move around the Sun in elliptical orbits, with the Sun at one focus of the ellipse.
Read the full explanation →Which one of the following statements is correct?
- A.Urea is produced in liver.
- B.Urea is produced in blood.
- C.Urea is produced from digestion of starch.
- D.Urea is produced in lung and kidney.
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Liver cells turn the toxic ammonia released from the breakdown of amino acids into urea through the ornithine cycle, also called the urea cycle.
Read the full explanation →Which one of the following is the correct sequence of passage of light in a compound microscope?
- A.Condenser-Objective lens-Eyepiece-Body tube
- B.Objective lens-Condenser-Body tube-Eyepiece
- C.Condenser-Objective lens-Body tube-Eyepiece
- D.Eyepiece-Objective lens-Body tube-Mirror
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Light passes through the condenser to the specimen, is picked up by the objective lens, travels up the body tube and reaches the eye through the eyepiece.
Read the full explanation →Which one of the following statements regarding haemoglobin is correct?
- A.Haemoglobin present in RBC can carry only oxygen but not carbon dioxide.
- B.Haemoglobin of RBC can carry both oxygen and carbon dioxide.
- C.Haemoglobin of RBC can carry only carbon dioxide.
- D.Haemoglobin is only used for blood clotting and not for carrying gases.
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It binds oxygen at its iron-containing haem groups and carries some carbon dioxide on its protein chains. Each haemoglobin molecule has four polypeptide chains and four haem groups, and each haem iron can hold one oxygen molecule, forming oxyhaemoglobin in the lungs.
Read the full explanation →Which one of the following statements regarding histone proteins is correct?
- A.Histones are proteins that are present in mitochondrial membrane.
- B.Histones are proteins that are present in nucleus in association with DNA.
- C.Histones are proteins associated with lipids in the cytosol.
- D.Histones are proteins associated with carbohydrates in the cytosol.
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They are the proteins around which DNA winds to form chromatin in the nucleus of eukaryotic cells. Histones are small basic proteins, rich in the positively charged amino acids lysine and arginine, which attract the negatively charged phosphate groups of DNA.
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