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25. Pick the correct statement(s) with respect to the inter-conversion of the topoisomers of a circularly closed double stranded DNA. (A) Only one strand needs to be cut (B) Both […]

24. A mutation in the operator locus of lac operon that confers constitutive expression of β- galactosidase is . (A) cis dominant (B) trans dominant (C) co-dominant (D) dominant negative […]

23. A cDNA was synthesized from the mRNA of a eukaryotic gene. After cloning and sequence analysis, the double-stranded cDNA of 614 bp revealed 125 bp 5′-UTR and 120 bp […]

22. Which of the following statement(s) is/are CORRECT for lac repressor expressed from the lacI gene? (A) The lac repressor is allosterically controlled and it binds to lac operator (B) […]

21. Which of the following statement(s) is/are CORRECT about ‘stringent response’ in bacteria? (A) It is linked to reduced growth rate (B) Guanosine tetraphosphate (ppGpp) alone is sufficient to trigger […]

20. The 5′ cap of eukaryotic mRNAs contains (A) a modified guanine nucleotide (B) a modified adenine nucleotide (C) a modified cytosine nucleotide (D) a modified uracil nucleotide 5′ Cap […]

19. The first evidence of ‘gene transfer’ was demonstrated in 1928 by (A) Joshua Lederberg in Escherichia coli (B) Frederick Griffith in Streptococcus pneumoniae  (C) Joshua Lederberg in bacteriophages (D) […]

18. Which of the following statement(s) about eukaryotic DNA topoisomerase is/are correct? (A) Topoisomerase I creates transient single-strand breaks (B) Topoisomerase I creates transient double-strand breaks (C) Topoisomerase II creates […]

17. Adenine constitutes 0.16 mole fraction in a given single-stranded DNA. What is the mole fraction of uracil in the resultant RNA, if this entire DNA fragment is transcribed? (A) […]

16. Which one of the following has a catalytic RNA? (A) Ribonuclease H (B) Ribozyme (C) RNA polymerase I (D) RNA polymerase II Catalytic RNA: Which One of the Following […]