Q: Which equation correctly represents the direction of RNA synthesis by RNA polymerase?

$$\text{RNA is synthesized in the 5' \rightarrow 3' direction}$$

Question 1

Which of the following statements best describes the role of sigma protein in bacterial transcription initiation?

Accepted Answer

Sigma protein recognizes promoter regions and orients RNA polymerase to the correct DNA strand.

Question 2

During transcription in bacteria, which sequence is typically found about 10 bases upstream of the transcription start site?

Accepted Answer

The TATAAT sequence (−10 box)

Question 3

What is the primary difference between RNA polymerase in bacteria and eukaryotes?

Accepted Answer

Bacteria have one RNA polymerase, while eukaryotes have at least three distinct types.

Question 4

Which of the following best explains why the direction of RNA polymerase movement is determined during transcription initiation?

Accepted Answer

The orientation of the promoter determines which DNA strand is used as the template.

Question 5

In eukaryotic cells, what is the function of the 5' cap added to pre-mRNA?

Accepted Answer

It enables ribosomes to bind and protects the RNA from degradation.

Question 6

Which equation correctly represents the direction of RNA synthesis by RNA polymerase?

Accepted Answer

$$	ext{RNA is synthesized in the 5' ightarrow 3' direction}$$

Question 7

A mutation prevents the formation of the poly(A) tail in eukaryotic mRNA. Which outcome is most likely?

Accepted Answer

The mRNA will be rapidly degraded and translation will be impaired.

Question 8

Which of the following is TRUE regarding introns and exons in eukaryotic genes?

Accepted Answer

Exons are present in the mature mRNA.

Question 9

What is the role of small nuclear ribonucleoproteins (snRNPs) in RNA processing?

Accepted Answer

They catalyze the removal of introns by forming the spliceosome.

Question 10

During bacterial transcription termination, what structure forms in the RNA and what is its effect?

Accepted Answer

A hairpin loop forms, causing RNA polymerase to separate from the RNA transcript.

Question 11

Which of the following best describes the process of RNA splicing in eukaryotes?

Accepted Answer

snRNPs bind to exon-intron boundaries, form a spliceosome, and remove introns as a lariat.

Question 12

A scientist heats viral DNA to form single-stranded DNA and incubates it with viral mRNA. Loops form along the hybrid molecules. What do these loops represent?

Accepted Answer

Stretches of DNA not present in mature mRNA, corresponding to introns.

Question 13

Which of the following is a consequence of alternative splicing in eukaryotes?

Accepted Answer

A single gene can produce multiple mRNAs and proteins.

Question 14

Which event occurs after splicing and addition of the cap and tail to pre-mRNA in eukaryotes?

Accepted Answer

The product is a mature mRNA ready for translation.

Question 15

Which of the following is NOT a difference between bacterial and eukaryotic transcription?

Accepted Answer

Both bacteria and eukaryotes use a poly(A) signal for termination.

Question 16

Which of the following best describes the relationship between the coding strand of DNA and the mRNA produced during transcription?

Accepted Answer

The coding strand is identical to the mRNA except that T is replaced by U.

Question 17

Which of the following is a function of untranslated regions (UTRs) in mature mRNA?

Accepted Answer

They regulate translation and stability of the mRNA.

Question 18

A researcher observes that a bacterial gene is not being transcribed. Which of the following is a plausible explanation based on promoter function?

Accepted Answer

The sigma protein cannot bind to the promoter region.

Question 19

Which of the following steps occurs LAST during the splicing of a primary RNA transcript?

Accepted Answer

The lariat is cut out and the two exons are linked.

Transcription, RNA Processing, and Translation: Study Notes

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