Q: Which of the following equations correctly represents the reaction catalyzed by RNA polymerase during chain elongation?

$$\text{RNA}_n + \text{rNTP} \rightarrow \text{RNA}_{n+1} + \text{PP}_i$$

Question 1

Which of the following best describes the central dogma of molecular biology?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 2

Which enzyme is responsible for synthesizing RNA from a DNA template during transcription?

Accepted Answer

RNA polymerase

Question 3

In prokaryotes, what is the function of the sigma ($$ \sigma ) $$factor in transcription?

Accepted Answer

It recognizes the promoter and initiates transcription.

Question 4

Which of the following statements about the template and coding strands during transcription is correct?

Accepted Answer

The coding strand is equivalent in sequence to the RNA product (except T is replaced by U).

Question 5

Which of the following is a consensus sequence found in prokaryotic promoters that is recognized by the sigma factor?

Accepted Answer

$$5'\ 	ext{TATAAT}\ 3'$$

Question 6

Which of the following best explains why RNA polymerase has a higher error rate than DNA polymerase?

Accepted Answer

RNA polymerase has less efficient 3'→5' exonuclease activity compared to DNA polymerase.

Question 7

Which of the following is NOT a function of microRNA (miRNA)?

Accepted Answer

Carrying genetic information for protein synthesis

Question 8

What is the main difference between intrinsic (Rho-independent) and Rho-dependent termination in prokaryotic transcription?

Accepted Answer

Intrinsic termination involves a hairpin structure followed by uracils, while Rho-dependent termination requires the rho protein to break the RNA-DNA hybrid.

Question 9

Which of the following equations correctly represents the reaction catalyzed by RNA polymerase during chain elongation?

Accepted Answer

$$	ext{RNA}_n + 	ext{rNTP} ightarrow 	ext{RNA}_{n+1} + 	ext{PP}_i$$

Question 10

A mutation in the Pribnow box (−10 region) of a prokaryotic promoter would most likely result in which of the following?

Accepted Answer

Reduced or abolished transcription initiation

Question 11

Which of the following best describes the directionality of RNA synthesis during transcription?

Accepted Answer

RNA is synthesized in the 5' to 3' direction, using the template DNA strand read 3' to 5'.

Question 12

Which of the following is a real-world application of small interfering RNAs (siRNAs)?

Accepted Answer

Triggering the degradation of foreign RNA molecules, such as viral RNA

Question 13

Which of the following statements about the nucleolus is correct?

Accepted Answer

It is primarily involved in ribosomal RNA synthesis and ribosome assembly.

Question 14

Which of the following best explains why CRISPR-Cas systems are found only in prokaryotes?

Accepted Answer

CRISPR-Cas is an adaptive immune system evolved specifically in bacteria and archaea to defend against foreign genetic elements.

Question 15

Which of the following is a key difference between DNA replication and transcription?

Accepted Answer

DNA replication copies the entire genome, while transcription copies only specific genes.

Question 16

Which of the following best describes the role of tRNA during translation?

Accepted Answer

It carries amino acids to the ribosome and matches them to the coded mRNA message.

Question 17

Which of the following is a plausible consequence of a mutation that disrupts the formation of a hairpin structure in the RNA during intrinsic termination in bacteria?

Accepted Answer

Transcription will not terminate efficiently, leading to longer RNA transcripts.

Question 18

Which of the following best describes the function of noncoding RNAs (ncRNAs)?

Accepted Answer

They function as RNA molecules without being translated, often regulating gene expression.

Transcription and the Genetic Code: Mechanisms and Regulation in Prokaryotes

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