Question 1

Which of the following correctly matches a sequence or factor with its function and the organismal domain in which it is found?

Accepted Answer

The Pribnow box is found in prokaryotes and is involved in transcription initiation.

Question 2

A mutation changes the -10 sequence in a bacterial promoter. What is the most likely effect on gene expression?

Accepted Answer

Transcription will decrease because the sigma factor cannot recognize the promoter efficiently.

Question 3

Which of the following best describes the role of the 5' untranslated region (5' UTR) in eukaryotic mRNA?

Accepted Answer

It contains regulatory elements that influence translation efficiency.

Question 4

During eukaryotic transcription, which RNA polymerase is responsible for synthesizing mRNA, and which promoter element does it typically recognize?

Accepted Answer

RNA polymerase II; TATA box

Question 5

A researcher is analyzing a gene with the following features: a TATA box, a CAAT box, and a G-C rich box upstream of the transcription start site. In which type of organism is this gene most likely found, and what process are these elements involved in?

Accepted Answer

Eukaryote; transcription

Question 6

Which of the following statements about the directionality of nucleic acid synthesis is correct?

Accepted Answer

DNA and RNA polymerases synthesize nucleic acids in the 5' to 3' direction.

Question 7

A mutation introduces a premature stop codon into the coding region of a gene. What is the most likely consequence at the protein level?

Accepted Answer

The protein will be truncated and likely nonfunctional.

Question 8

Which of the following best describes the function of the Shine-Dalgarno sequence?

Accepted Answer

It is a ribosome binding site in prokaryotic mRNA, facilitating translation initiation.

Question 9

Which of the following is a key difference between prokaryotic and eukaryotic gene expression?

Accepted Answer

Eukaryotes compartmentalize transcription and translation, while prokaryotes couple these processes.

Question 10

A scientist is using PCR to amplify a DNA fragment. Which of the following is NOT required for a successful PCR reaction?

Accepted Answer

RNA primers

Question 11

Which of the following best explains why a mutation in the origin of replication (Ori) can be lethal to a cell?

Accepted Answer

It prevents the initiation of DNA replication, so the cell cannot duplicate its genome.

Question 12

Which of the following is true regarding the process of splicing in eukaryotes?

Accepted Answer

Splicing is performed by snRNPs, which remove introns from pre-mRNA.

Question 13

A DNA sequence is found to have a mutation in the Kozak sequence. What is the most likely effect on gene expression in a eukaryotic cell?

Accepted Answer

Translation initiation will be less efficient, reducing protein synthesis.

Question 14

Which of the following best describes the function of a promoter in gene expression?

Accepted Answer

It is the binding site for RNA polymerase to initiate transcription.

Question 15

A student is analyzing a DNA gel after PCR and sees multiple bands instead of a single expected band. Which of the following is the most likely explanation?

Accepted Answer

The primers were not specific and annealed to multiple sites.

Question 16

Which of the following best explains how a single nucleotide change in DNA can lead to a disease phenotype?

Accepted Answer

It can alter the amino acid sequence of a protein, potentially affecting its function.

Question 17

Which of the following is a correct statement about the start codon?

Accepted Answer

It is typically AUG and signals the start of translation in both prokaryotes and eukaryotes.

Question 18

Which of the following best describes the function of the CAAT box in eukaryotic genes?

Accepted Answer

It is a core promoter element that enhances transcription efficiency.

Question 19

A patient has a genetic disorder caused by a mutation that affects splicing. Which of the following is the most likely molecular consequence?

Accepted Answer

The mature mRNA will contain introns, potentially leading to a dysfunctional protein.

Question 20

Which of the following best describes the role of the terminator sequence in gene expression?

Accepted Answer

It signals RNA polymerase to stop transcription.

Key Terms and Concepts in DNA Replication, Transcription, and Translation

Guida di studio - Domande di pratica

Study guide - Flashcard