Question 1

Which of the following best describes the main difference between transcription and replication in eukaryotic cells?

Accepted Answer

Replication copies the entire DNA molecule, while transcription only copies specific genes as needed.

Question 2

A mutation occurs in the -10 consensus sequence (Pribnow box) of a bacterial promoter, changing TATAAT to TATGAT. What is the most likely effect on transcription?

Accepted Answer

Transcription initiation will decrease because RNA polymerase binds less efficiently.

Question 3

Which of the following statements about the directionality of transcription is correct?

Accepted Answer

RNA is synthesized in the 5' to 3' direction, antiparallel to the template strand.

Question 4

Which enzyme is responsible for catalyzing the synthesis of RNA during transcription in both prokaryotes and eukaryotes?

Accepted Answer

RNA polymerase

Question 5

What is the role of the sigma factor in bacterial transcription?

Accepted Answer

It directs RNA polymerase to specific promoter sequences to initiate transcription.

Question 6

Which of the following is a feature of rho-independent termination in bacteria?

Accepted Answer

A hairpin structure forms in the RNA followed by a string of uracils.

Question 7

A researcher treats bacterial cells with rifampicin, an antibiotic that inhibits RNA polymerase. What is the expected outcome?

Accepted Answer

Bacterial transcription is inhibited, but eukaryotic transcription is unaffected.

Question 8

Which of the following best explains why RNA can form more secondary structures than DNA?

Accepted Answer

RNA is usually single-stranded, allowing complementary regions within the same molecule to pair and form structures like hairpins.

Question 9

Which of the following is NOT a component of a typical transcription unit in DNA?

Accepted Answer

Origin of replication

Question 10

In eukaryotes, which RNA polymerase is primarily responsible for transcribing genes that encode proteins?

Accepted Answer

RNA polymerase II

Question 11

A mutation in the regulatory promoter of a eukaryotic gene most likely affects which aspect of transcription?

Accepted Answer

The rate at which transcription is initiated

Question 12

Which of the following best describes a consensus sequence?

Accepted Answer

A sequence that represents the most commonly found nucleotides at a specific location in DNA or RNA

Question 13

Which of the following is true regarding the direction of transcription and the template strand?

Accepted Answer

Transcription proceeds in the 3' to 5' direction on the template strand, producing a 5' to 3' RNA that is antiparallel to the template.

Question 14

Which of the following is a function of ribosomal RNA (rRNA)?

Accepted Answer

Catalyzes peptide bond formation during translation

Question 15

Which of the following best explains why not all genes are transcribed at all times in a cell?

Accepted Answer

Transcribing all genes at once would be highly inefficient and unnecessary since not all gene products are needed at the same time.

Question 16

Which of the following is true about the role of transcription factors in eukaryotic transcription?

Accepted Answer

They bind to DNA sequences and help assemble the basal transcription apparatus at the promoter.

Question 17

A bacterial gene is part of an operon and is transcribed as part of a polycistronic mRNA. What does this mean?

Accepted Answer

The gene is transcribed together with other genes into a single mRNA molecule that encodes multiple proteins.

Question 18

Which of the following best describes the function of the core enzyme of bacterial RNA polymerase?

Accepted Answer

It catalyzes the elongation of the RNA molecule by adding RNA nucleotides.

Question 19

Which of the following is a key difference between eukaryotic and bacterial transcription initiation?

Accepted Answer

Bacterial transcription initiation involves sigma factors, while eukaryotic transcription initiation involves general transcription factors and chromatin remodeling.

Question 20

A mutation in the gene encoding the rho factor in bacteria would most directly affect which process?

Accepted Answer

Termination of transcription at rho-dependent terminators

Genetic Principles: Chapter 13 – Transcription

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