Question 1

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

Accepted Answer

Information flows from DNA to RNA to protein.

Question 2

In prokaryotic cells, what allows translation of mRNA to begin before transcription is complete?

Accepted Answer

Lack of compartmentalization between DNA and ribosomes.

Question 3

Which sequence is commonly found about 10 base pairs upstream of the transcription start site in bacterial promoters?

Accepted Answer

TATAAT (the Pribnow box)

Question 4

What is the role of the sigma ($$ \sigma ) $$factor in bacterial transcription?

Accepted Answer

It promotes binding of RNA polymerase to the -35 and -10 promoter elements.

Question 5

During transcription in eukaryotes, which RNA polymerase is responsible for synthesizing mRNA?

Accepted Answer

RNA polymerase II

Question 6

Which of the following statements about RNA processing in eukaryotes is TRUE?

Accepted Answer

Eukaryotic mRNA undergoes capping, polyadenylation, and splicing before translation.

Question 7

A mutation in the AAUAAA sequence of a eukaryotic gene would most likely affect which process?

Accepted Answer

Cleavage and polyadenylation of the pre-mRNA

Question 8

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

Accepted Answer

It facilitates ribosome binding during translation.

Question 9

What is the main difference between transcription termination in prokaryotes and eukaryotes?

Accepted Answer

In eukaryotes, RNA cleavage is more important than termination signals for determining the 3' end of transcripts.

Question 10

Which of the following best explains why errors in RNA molecules are less critical than errors in DNA replication?

Accepted Answer

RNA molecules are transient and have a high turnover rate.

Question 11

A scientist isolates a eukaryotic cell and finds a large nucleolus occupying 25% of the nuclear volume. What can be inferred about the cell's activity?

Accepted Answer

The cell has a high rate of ribosome synthesis and protein production.

Question 12

Which of the following is TRUE regarding alternative splicing?

Accepted Answer

It allows a single gene to produce multiple protein products.

Question 13

Which enzyme catalyzes the process of reverse transcription in retroviruses?

Accepted Answer

Reverse transcriptase

Question 14

During bacterial transcription, what is the consequence of a mutation in the Pribnow box?

Accepted Answer

Transcription will initiate at random sites.

Question 15

Which of the following statements about the direction of RNA synthesis is correct?

Accepted Answer

RNA is synthesized in the 5' to 3' direction, with nucleotides added to the 3' end.

Question 16

A patient has a genetic disorder caused by a splicing error. Which cellular structure is most likely malfunctioning?

Accepted Answer

Spliceosome

Question 17

Which of the following is NOT a function of the poly(A) tail in eukaryotic mRNA?

Accepted Answer

Initiating transcription

Question 18

Which of the following best describes the role of topoisomerases during transcription elongation?

Accepted Answer

They unwind the DNA double helix ahead of RNA polymerase and prevent supercoiling.

Question 19

Which of the following is a plausible consequence of a mutation that prevents the formation of the hairpin loop in bacterial transcription termination?

Accepted Answer

Transcription will require the rho factor for termination.

Question 20

A researcher is studying a eukaryotic gene and finds that its promoter is located downstream of the transcription start site. Which RNA polymerase is most likely responsible for transcribing this gene?

Accepted Answer

RNA polymerase III

Gene Expression I: Transcription – Study Notes (Becker's World of the Cell, Ch. 18)

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