2019 GS Paper I, all questions

UPSC Prelims 2019 · GS Paper I

Question 93: Science and Technology

With reference to the recent developments in science, which one of the following statements is not correct?

aFunctional chromosomes can be created by joining segments of DNA taken from cells of different species.
bPieces of artificial functional DNA can be created in laboratories.
cA piece of DNA taken out from an animal cell can be made to replicate outside a living cell in a laboratory.
dCells taken out from plants and animals can be made to undergo cell division in laboratory petri dishes.

AnswerUPSC’s answer is (a).

Option (a) is the statement UPSC treats as not correct. Pieces of artificial functional DNA can be made in laboratories, DNA taken from an animal cell can be copied outside a living cell, as in PCR, and cells from plants and animals can be grown and made to divide in culture dishes, which is tissue culture. A functional chromosome built by joining DNA segments from different species is not treated as an established development.

Why each option is right or wrong
  • (a) Correct: this is the statement UPSC marks as not correct.
  • (b) True: artificial DNA can be synthesised in laboratories.
  • (c) True: DNA can be replicated outside a living cell, as in PCR.
  • (d) True: plant and animal cells divide in culture dishes.

Worth knowing: Artificial chromosomes carrying DNA from other species, such as yeast artificial chromosomes, exist, so option (a) is arguable; UPSC's key marks it as the incorrect statement.

Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.

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Source: UPSC, Civil Services (Preliminary) Examination 2019, General Studies Paper I, Series A. The paper on upsc.gov.in.