Question 1

Which of the following best describes the difference between the coding strand and the template strand during transcription?

Accepted Answer

The template strand is used by RNA polymerase to synthesize a complementary RNA molecule, while the coding strand has the same sequence as the RNA (except T is replaced by U).

Question 2

Which of the following RNA secondary structures is depicted in the image showing a single-stranded region flanked by two double-stranded regions on either side?

Accepted Answer

Internal loop

Question 3

Which of the following is a function of the 5' cap added to eukaryotic mRNA during processing?

Accepted Answer

It signals the start of translation by providing a binding site for ribosomes.

Question 4

Which consensus sequence is most commonly found at the -10 position in bacterial promoters?

Accepted Answer

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

Question 5

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

Accepted Answer

Promoter recognition and initiation

Question 6

Which of the following statements about Rho-independent (intrinsic) termination in bacteria is correct?

Accepted Answer

It involves the formation of a GC-rich stem-loop followed by a poly-U tail in the mRNA.

Question 7

Which of the following is NOT a function of eukaryotic RNA polymerase II?

Accepted Answer

Transcription of tRNA genes

Question 8

Which of the following best explains why bacterial RNA polymerase does not have exonuclease proofreading activity?

Accepted Answer

RNA is a temporary molecule and errors are less detrimental than in DNA.

Question 9

Which of the following is a key difference between bacterial and eukaryotic gene structure?

Accepted Answer

Eukaryotic genes contain introns and require extensive RNA processing before translation.

Question 10

Which of the following modifications is added to the 3' end of eukaryotic mRNA during processing?

Accepted Answer

A poly(A) tail

Question 11

A researcher discovers a eukaryotic gene that produces multiple protein isoforms in different tissues. Which mechanism most likely explains this observation?

Accepted Answer

Alternative splicing of pre-mRNA

Question 12

Which of the following is a role of small nuclear RNA (snRNA) in eukaryotic cells?

Accepted Answer

It helps remove introns from pre-mRNA during splicing.

Question 13

Which of the following best describes the function of enhancer sequences in eukaryotic transcription?

Accepted Answer

They increase the level of transcription by binding activator proteins, which interact with the promoter.

Question 14

During eukaryotic mRNA splicing, which sequence is nearly invariant at the 5' splice site of an intron?

Accepted Answer

$$	ext{GU}$$

Question 15

Which of the following is a plausible consequence of increased alternative splicing in cancer cells?

Accepted Answer

Increased splicing variants, cell proliferation and metastasis

Question 16

Which of the following best describes the torpedo model of transcription termination in eukaryotes?

Accepted Answer

An exonuclease degrades the RNA downstream of the poly(A) site and displaces RNA polymerase II from the DNA.

Question 17

Which of the following is NOT a function shared by the 5' cap and 3' poly(A) tail of eukaryotic mRNA?

Accepted Answer

Facilitating the removal of exons from pre-mRNA

Question 18

Which of the following statements about group I and group II introns is correct?

Accepted Answer

They are capable of self-splicing and are classified as ribozymes.

Question 19

A mutation eliminates the CAAT box from a eukaryotic gene promoter. Which of the following is the most likely effect?

Accepted Answer

Reduced transcription efficiency due to loss of a promoter element.

Question 20

Which of the following best explains why translation and transcription can occur simultaneously in bacteria but not in eukaryotes?

Accepted Answer

Bacterial transcription and translation both occur in the cytoplasm, while in eukaryotes, transcription occurs in the nucleus and translation in the cytoplasm.

Chapter 8

Guida di studio - Domande di pratica

Study guide - Flashcard