Question 1

Which of the following statements best describes the process of transcription in prokaryotes?

Accepted Answer

Transcription is initiated when the sigma factor binds to the promoter, allowing RNA polymerase to start RNA synthesis.

Question 2

During translation in bacteria, which amino acid is incorporated at the start codon, and what is its codon?

Accepted Answer

N-formylmethionine; codon $AUG$

Question 3

Which type of RNA is responsible for bringing amino acids to the ribosome during protein synthesis?

Accepted Answer

Transfer RNA (tRNA)

Question 4

A mutation changes the DNA sequence from $5'\ TTT\ GTT\ AAT\ CAG\ CAT\ CTT\ 3'$ to $5'\ TTT\ GTT\ AAT\ CAG\ CAT\ CTC\ 3'$. What is the most likely effect on the protein product?

Accepted Answer

There will be a single amino acid substitution at the C-terminus.

Question 5

Which of the following best explains why eukaryotic mRNA must be processed before translation?

Accepted Answer

Eukaryotic mRNA contains introns that must be removed and requires a 5' cap and poly(A) tail for stability and export.

Question 6

Which of the following is a function of chaperone proteins in cells?

Accepted Answer

They assist in the folding and refolding of proteins, especially under stress conditions.

Question 7

In bacteria, what is the role of the Pribnow box during transcription?

Accepted Answer

It is a consensus sequence in the promoter region that helps position RNA polymerase for transcription initiation.

Question 8

Which of the following best describes polycistronic mRNA?

Accepted Answer

An mRNA that contains multiple open reading frames, each encoding a different protein.

Question 9

A bacterial cell is exposed to heat shock. Which cellular response is most likely to occur?

Accepted Answer

Upregulation of chaperone proteins to refold denatured proteins.

Question 10

Which of the following is true regarding the Sec and Tat translocase systems in bacteria?

Accepted Answer

Sec exports unfolded proteins and inserts integral membrane proteins; Tat exports folded proteins.

Question 11

Which of the following codons is NOT a stop codon in the genetic code?

Accepted Answer

$AUG$

Question 12

A mutation in the promoter region of a gene reduces the binding affinity of RNA polymerase. What is the most likely consequence?

Accepted Answer

Decreased transcription of the gene.

Question 13

Which of the following is a key difference between transcription in eukaryotes and prokaryotes?

Accepted Answer

Eukaryotes use multiple RNA polymerases and transcription factors, while prokaryotes use a single RNA polymerase and sigma factors.

Question 14

Which of the following best describes the function of ribosomal RNA (rRNA)?

Accepted Answer

It forms the structural and catalytic core of the ribosome, facilitating protein synthesis.

Question 15

A scientist isolates a bacterial mRNA that encodes three different proteins. What is the most likely structure of this mRNA?

Accepted Answer

It is polycistronic, containing multiple open reading frames.

Question 16

Which of the following sequences is most likely to be found at the transcription start site in bacteria?

Accepted Answer

$TATAAT$

Question 17

Which process is responsible for synthesizing RNA from a DNA template?

Accepted Answer

Transcription

Question 18

A protein destined for secretion in a Gram-negative bacterium is most likely to be exported by which system?

Accepted Answer

Type I-VI secretion systems

Question 19

Which of the following is a consequence of the degeneracy of the genetic code?

Accepted Answer

Multiple codons can specify the same amino acid.

Question 20

Which of the following is true regarding the directionality of RNA synthesis during transcription?

Accepted Answer

RNA is synthesized in the 5' to 3' direction.

Genetic Information Flow: Replication, Transcription, and Translation

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