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, which feature 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 factor in bacterial transcription?

Accepted Answer

It promotes binding of RNA polymerase to specific promoter sequences.

Question 5

During transcription elongation, in which direction is the RNA strand synthesized?

Accepted Answer

5' to 3' direction

Question 6

Which of the following is TRUE regarding RNA polymerase proofreading?

Accepted Answer

RNA polymerase possesses weak proofreading abilities and can remove incorrect nucleotides via backtracking.

Question 7

Which of the following statements about eukaryotic RNA polymerases is CORRECT?

Accepted Answer

RNA polymerase III synthesizes tRNA and is sensitive to a-amanitin only at high concentrations.

Question 8

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

Accepted Answer

Addition of the poly(A) tail

Question 9

Which of the following best explains why most bacterial mRNAs do not require extensive processing before translation?

Accepted Answer

Bacterial mRNAs are synthesized in a form ready for translation and lack introns.

Question 10

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

Accepted Answer

It protects mRNA from nucleases and aids in ribosome binding during translation.

Question 11

A patient is found to have a genetic disease caused by improper removal of introns from pre-mRNA. Which cellular structure is most likely malfunctioning?

Accepted Answer

Spliceosome

Question 12

Which of the following sequences marks the typical 5' and 3' boundaries of an intron in eukaryotic pre-mRNA?

Accepted Answer

5' GU ... AG 3'

Question 13

Alternative splicing allows for which of the following outcomes?

Accepted Answer

Production of multiple protein products from a single gene

Question 14

Which enzyme is responsible for catalyzing the addition of the poly(A) tail to eukaryotic mRNA?

Accepted Answer

Poly(A) polymerase

Question 15

Which of the following is a consequence of the existence of introns in eukaryotic genes?

Accepted Answer

Introns allow for exon shuffling, contributing to the evolution of new protein-coding genes.

Question 16

Which of the following statements about the nucleolus is CORRECT?

Accepted Answer

The nucleolus is the site of ribosomal RNA synthesis and ribosomal subunit assembly.

Question 17

A scientist isolates a eukaryotic RNA molecule that contains both exons and introns, a 5' cap, and a poly(A) tail. Which stage of RNA processing is most likely incomplete?

Accepted Answer

Splicing of introns

Question 18

Which of the following best describes the role of general transcription factors in eukaryotic transcription?

Accepted Answer

They are required for RNA polymerase binding to promoters and formation of the preinitiation complex.

Question 19

Which process is catalyzed by the enzyme reverse transcriptase, and in which biological context is it most commonly found?

Accepted Answer

Reverse transcription of RNA to DNA in retroviruses

Gene Expression: I. Transcription – Cell Biology Study Notes

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