Question 1

Which of the following statements 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 in the 3' to 5' direction.

Question 2

Which of the following is a unique feature of eukaryotic mRNA processing that is NOT found in prokaryotes?

Accepted Answer

Addition of a 5' cap structure consisting of 7-methylguanosine via a 5',5'-triphosphate linkage.

Question 3

Which RNA polymerase is responsible for transcribing tRNA genes in eukaryotes?

Accepted Answer

RNA polymerase III

Question 4

A mutation in the -10 region (TATAAT) of a prokaryotic promoter would most likely affect which process?

Accepted Answer

The initiation of transcription by RNA polymerase

Question 5

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

Accepted Answer

RNA polymerase lacks a 3' to 5' exonuclease proofreading activity.

Question 6

Which of the following is a function of small nuclear RNAs (snRNAs)?

Accepted Answer

They participate in the splicing of introns from pre-mRNA.

Question 7

A researcher isolates a catalytic RNA that can self-splice an intron using a guanine nucleotide as a cofactor. This RNA is most likely an example of:

Accepted Answer

A Group I intron

Question 8

Which of the following sequences signals the addition of the poly(A) tail during eukaryotic mRNA processing?

Accepted Answer

$$\mathrm{AAUAAA}$$

Question 9

Which of the following best describes the role of the 5' cap and 3' poly(A) tail in eukaryotic mRNA?

Accepted Answer

They protect mRNA from degradation and aid in translation initiation.

Question 10

Which of the following is TRUE regarding the 'RNA world' hypothesis?

Accepted Answer

It is supported by the discovery of ribozymes, which are catalytic RNAs.

Question 11

A eukaryotic gene contains several introns and exons. Which process ensures that only exons are joined together in the mature mRNA?

Accepted Answer

Splicing by the spliceosome

Question 12

Which of the following is a key difference between prokaryotic and eukaryotic gene expression?

Accepted Answer

Eukaryotic mRNAs are processed with a 5' cap, 3' poly(A) tail, and splicing.

Question 13

Which of the following best describes the function of the Shine-Dalgarno sequence in prokaryotic mRNAs?

Accepted Answer

It serves as a ribosome-binding site for translation initiation.

Question 14

Which of the following is a plausible consequence of a mutation that disrupts the GU/AG rule at the intron-exon boundaries in a eukaryotic gene?

Accepted Answer

Failure of the spliceosome to recognize and remove the intron, resulting in abnormal mRNA.

Question 15

Which of the following best explains why eukaryotic rRNA genes are present in multiple tandem copies within the nucleolus?

Accepted Answer

To meet the high cellular demand for ribosome production.

Question 16

Which of the following is a function of small nucleolar RNAs (snoRNAs)?

Accepted Answer

They are involved in the modification and processing of rRNA precursors.

Question 17

Which of the following statements about ribozymes is CORRECT?

Accepted Answer

They are RNA molecules with catalytic activity, such as self-splicing introns.

Question 18

A mutation in the gene encoding the sigma ($$\sigma) $$subunit of bacterial RNA polymerase would most likely affect which aspect of transcription?

Accepted Answer

The recognition and binding of specific promoter sequences

Question 19

Which of the following best describes the role of tRNA nucleotidyl transferase in tRNA processing?

Accepted Answer

It adds the CCA sequence to the 3' end of tRNA, which is essential for amino acid attachment.

Question 20

Which of the following is a key feature of housekeeping genes?

Accepted Answer

They are constitutively expressed at nearly constant levels in all cells.

RNA Metabolism: Transcription, RNA Processing, and Ribozymes

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