1) In bacteria, which of the following helps guide RNA polymerase to the -10 and

Question

1) In bacteria, which of the following helps guide RNA polymerase to the -10 and -35 box of the promoter?

a) regulator

b) basal transcription factor

c) inducer

d) sigma factor

e) TATA director

2) Listed below are the events of transcription initiation in a typical bacterial cell, but they are out of chronological order. Use this information to answer question 14.

i. Sigma binds to the promoter region.

ii. The double helix of DNA is unwound, breaking hydrogen bonds between complementary strands.

iii. Sigma binds to RNA polymerase.

iv. Sigma is released.

Which of the following puts the events in the correct chronological order?

a) ii, iii, iv, i

b) ii, iii, i, iv

c) iii, i, ii, iv

d) iii, ii, i, iv

3) Which of the following will trigger transcription to stop in a bacterial cell?

a) RNA polymerase releases when it reaches a distinct site termed the transcription-termination signal (“terminator”).

b) RNA polymerase releases when it reaches the poly (T) signal.

c) RNA polymerase releases when it reaches a stop codon.

d) RNA polymerase releases when it reaches the -10 box.

e) RNA polymerase releases when it reaches a telomere.

4) Which of the following protects the 5’ end of mRNA from enzymes that degrade RNA molecules?

a) small nuclear ribonucleoproteins (snRNPs)

b) promoter

c) Poly(A) tail

d) introns

e) Cap made of a modified guanine nucleotide

5) Which of the following triggers translation to stop causing the mRNA, tRNA, ribosome and newly synthesized polypeptide to release?

a) The ribosome reaches a stop codon.

b) A release factor enters the ribosome filling the A site.

c) The ribosome reaches the termination signal.

d) A and B are correct

e) A and C are correct

f) B and C are correct

Explanation / Answer

i.e the order as follows :-The double helix of DNA is unwound, breaking hydrogen bonds between complementary strandsàSigma binds to RNA polymeraseà Sigma binds to the promoter regionàSigma is released.

3.in bacterial cell trancreiption is stop when RNA polymerase releases when it reaches a stop codon which are present on DNA sequence

4. Poly (A) tail protects the 5’ ends of mRNA from enzymes that degrade RNA molecule.

5.both A and C ( the ribosomes reches a stop codon and the ribosomes reaches the termination signal ) trigger translation stop .

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