Question 1

Which of the following best describes the relationship between transcription, translation, and gene expression in a bacterial cell?

Accepted Answer

Transcription synthesizes mRNA from DNA, which is then translated into protein, together constituting gene expression.

Question 2

In prokaryotic transcription initiation, which sequence is recognized by the sigma factor to position RNA polymerase correctly?

Accepted Answer

The $$-10$$ and $$-35$$ promoter regions

Question 3

During transcription elongation in prokaryotes, which of the following occurs?

Accepted Answer

RNA polymerase synthesizes RNA in the $$5' \rightarrow 3'$$ direction.

Question 4

Which mechanism is involved in Rho-independent transcriptional termination in prokaryotes?

Accepted Answer

A stem-loop structure forms in the RNA followed by a poly-U sequence.

Question 5

Which of the following is TRUE about eukaryotic transcription compared to prokaryotic transcription?

Accepted Answer

Eukaryotic RNA polymerase requires general transcription factors to initiate transcription.

Question 6

Which modification is added to the $$5'$$ end of eukaryotic mRNA, and what is its primary function?

Accepted Answer

A methylated guanine cap; to protect mRNA from degradation and assist in ribosome binding.

Question 7

The Shine-Dalgarno sequence in prokaryotes is important for which process?

Accepted Answer

Translation initiation by aligning the ribosome with the start codon

Question 8

Aminoacyl tRNA synthetases are responsible for which critical step in translation?

Accepted Answer

Charging tRNAs with their corresponding amino acids

Question 9

Which of the following statements about the direction of translation in prokaryotes is correct?

Accepted Answer

Translation proceeds in the $$5' \rightarrow 3'$$ direction along the mRNA.

Question 10

Which elongation factor in prokaryotic translation is responsible for delivering aminoacyl-tRNA to the A site of the ribosome?

Accepted Answer

EF-Tu

Question 11

How does the ribosome catalyze peptide bond formation during translation?

Accepted Answer

Through the peptidyl transferase activity of rRNA in the large subunit

Question 12

A mutation changes a codon from UUU to UUC. What type of mutation is this, and what is its likely effect?

Accepted Answer

Silent mutation; no change in the amino acid sequence

Question 13

Which of the following best describes the randomness of mutations?

Accepted Answer

Mutations occur randomly with respect to an organism's needs.

Question 14

The Ames test is used to detect which of the following?

Accepted Answer

The mutagenic potential of chemical compounds

Question 15

Which DNA repair mechanism directly reverses the formation of thymine dimers caused by UV light?

Accepted Answer

Photoreactivation

Question 16

Which of the following statements about operons in bacteria is correct?

Accepted Answer

Operons allow coordinated regulation of genes with related functions.

Question 17

A riboswitch in a bacterial mRNA can regulate gene expression by:

Accepted Answer

Changing its secondary structure in response to a small molecule, affecting translation or transcription.

Question 18

Which of the following best describes a transposon?

Accepted Answer

A mobile genetic element that can move within the genome

Question 19

Which statement about suppressor mutations is correct?

Accepted Answer

Suppressor mutations can restore function lost by a primary mutation, sometimes in a different gene.

Question 20

Which of the following is an example of an in trans regulatory effect in bacteria?

Accepted Answer

A protein encoded by one gene regulates the expression of another gene located elsewhere in the genome.

Transcription, Translation, Gene Expression, and Regulation in Prokaryotes and Eukaryotes

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