Transcription And Regulation(Biochemistry ) Questions and Answers

Question 1. The complex of RNA polymerase, DNA template and new RNA transcript is called
  1.    replication bubble
  2.    none of these
  3.    transcription bubble
  4.    a translation bubble
Explanation:-
Answer: Option C. -> transcription bubble
Question 2. RNA polymerase in prokaryotes has a removable
  1.    both (a) and (b)
  2.    sigma subunit
  3.    alpha subunit
  4.    beta subunit
Explanation:-
Answer: Option B. -> sigma subunit
Question 3. Promoters for tRNAs are located
  1.    both (a) and (b)
  2.    upstream from the start codon
  3.    none of these
  4.    downstream from the start codon
Explanation:-
Answer: Option D. -> downstream from the start codon
Question 4. Rho-dependent termination of transcription in E. coli
  1.    both (a) and (b)
  2.    requires ATP
  3.    removes mRNA and holoenzyme from the DNA
  4.    requires about 50 nucleotides of uncomplexed mRNA
Explanation:-
Answer: Option A. -> both (a) and (b)
Question 5. The binding of lac repressor to DNA could be considered to be analogous to
  1.    uncompetitive inhibition of an enzyme
  2.    competitive inhibition of an enzyme
  3.    mixed-type inhibition of an enzyme
  4.    allosteric effects in enzyme regulation
Explanation:-
Answer: Option B. -> competitive inhibition of an enzyme
Question 6. Enhancers are regions that
  1.    bind RNA polymerase
  2.    are CAT box binding proteins
  3.    modulate transcription
  4.    are adjacent to the TATA box
Explanation:-
Answer: Option C. -> modulate transcription
Question 7. Multiple copies of 5S genes, located at a chromosomal site distinct from the other rRNA genes
  1.    are transcribed by rRNA polymerase III and the 5S rRNA
  2.    are transcribed by DNA polymerase I
  3.    are transcribed by rRNA polymerase II
  4.    are transcribed by rRNA polymerase I and the 5S rRNA
Explanation:-
Answer: Option A. -> are transcribed by rRNA polymerase III and the 5S rRNA
Question 8. Which of the following is necessary for transcription to occur?
  1.    DNA polymerase
  2.    RNA polymerase
  3.    Both DNA & RNA polymerase
  4.    DNA molecule
Explanation:-
Answer: Option C. -> Both DNA & RNA polymerase
Question 9. Transcription by E. coli polymerase occurs in
  1.    four phases known as initiation, propagation, elongation and termination
  2.    three phases known as initiation, elongation and termination
  3.    two phases known as initiation and termination
  4.    None of these
Explanation:-
Answer: Option B. -> three phases known as initiation, elongation and termination
Question 10. Each tRNA molecule has a cloverleaf secondary structure consisting of
  1.    three stem loops
  2.    four stem loops
  3.    two stem loops
  4.    either (a) or (b)
Explanation:-
Answer: Option A. -> three stem loops
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