πŸ“Š Molecular Biology and Genetics
Q. During transcription,
  • (A) DNA gyrase introduces negative supercoils and DNA topoisomerase I removes negative supercoils
  • (B) DNA topoisomerase I introduces negative supercoils and DNA gyrase removes negative supercoils
  • (C) Both DNA gyrase and DNA topoisomearse I introduce negative supercoils
  • (D) Both DNA gyrase and DNA topoisomearse I remove negative supercoils
πŸ’¬ Discuss
βœ… Correct Answer: (C) Both DNA gyrase and DNA topoisomearse I introduce negative supercoils
πŸ“Š Molecular Biology and Genetics
Q. What will be the binding status of regulatory proteins in lac operon when concentrations of both lactose and glucose are very low in the culture medium?
  • (A) Only the repressor remains bound to the operator
  • (B) Only the cyclic AMP-Catabolic Activator Protein (cAMP-CAP) complex remains bound to the CAP binding site
  • (C) Neither the repressor nor cAMP-CAP complex remain bound to their respective binding sites
  • (D) Both the repressor and cAMP-CAP complex remain bound to their respective binding sites
πŸ’¬ Discuss
βœ… Correct Answer: (D) Both the repressor and cAMP-CAP complex remain bound to their respective binding sites
πŸ“Š Molecular Biology and Genetics
Q. The 5' ends of the mature forms of the prokaryotic mRNAs and tRNAs are
  • (A) A triphosphate group in mRNAs and a monophosphate group in tRNAs
  • (B) Triphosphate groups in both mRNAs and tRNAs
  • (C) Monophosphate groups in both mRNAs and tRNAs
  • (D) A monophosphate group in mRNAs and a triphosphate group in tRNAs
πŸ’¬ Discuss
βœ… Correct Answer: (A) A triphosphate group in mRNAs and a monophosphate group in tRNAs
πŸ“Š Molecular Biology and Genetics
Q. Nuclease-hypersensitive sites in the chromosomes are sites that appear to be
  • (A) H2 and H4 histone free
  • (B) H1 and H2 histone free
  • (C) H3 and H4 histone free
  • (D) Nucleosome free
πŸ’¬ Discuss
βœ… Correct Answer: (D) Nucleosome free
πŸ“Š Molecular Biology and Genetics
Q. How many different protein sequences of 100 residues can be generated using 20 standard amino acids?
  • (A) 10020
  • (B) 100 × 20
  • (C) 20100
  • (D) 100! × 20!
πŸ’¬ Discuss
βœ… Correct Answer: (C) 20100
πŸ“Š Molecular Biology and Genetics
Q. The G + C content of bacteriophage M13 double stranded DNA is 68%. What would you expect the G + C content of its mRNA?
  • (A) About 68%
  • (B) About 34%
  • (C) About 32%
  • (D) About 86%
πŸ’¬ Discuss
βœ… Correct Answer: (A) About 68%
πŸ“Š Molecular Biology and Genetics
Q. Efficient expression of a heterologous protein product is influenced by
  • (A) Transcriptional efficiency
  • (B) Copy number of the plasmid
  • (C) Codon bias
  • (D) All of the above
πŸ’¬ Discuss
βœ… Correct Answer: (D) All of the above
πŸ“Š Molecular Biology and Genetics
Q. The 4-amino or 4-keto group of pyrimidine bases is located in the
  • (A) Major groove of the double stranded DNA
  • (B) Minor groove of the double stranded DNA
  • (C) Minor groove of the B form DNA but not the A form DNA
  • (D) Major groove of the B form DNA but not the A form DNA
πŸ’¬ Discuss
βœ… Correct Answer: (A) Major groove of the double stranded DNA
πŸ“Š Molecular Biology and Genetics
Q. RNA is very much susceptible to hydrolysis in alkali because
  • (A) It contains uracil residues in its structure
  • (B) its 2'-OH group participate in intramolecular cleavage of phosphodiester backbone
  • (C) Cleavage occurs in the glycosylic bonds of purine bases
  • (D) Cleavage occurs in the glycosylic bonds of pyrimidine bases
πŸ’¬ Discuss
βœ… Correct Answer: (B) its 2'-OH group participate in intramolecular cleavage of phosphodiester backbone

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