Question 1

Which of the following best describes the role of the TATA box in eukaryotic transcription initiation?

Accepted Answer

It serves as a promoter element that recruits general transcription factors, positioning RNA polymerase II correctly at the start site.

Question 2

During transcription elongation, in which direction does RNA polymerase synthesize the new RNA strand?

Accepted Answer

From the 5' to 3' direction, using the template strand as a template.

Question 3

Which of the following modifications occurs at the 5' end of a newly synthesized pre-mRNA in eukaryotes?

Accepted Answer

Addition of a 7-methylguanosine cap

Question 4

A mutation destroys the polyadenylation signal (AAUAAA) in a gene. What is the most likely consequence for the mRNA produced from this gene?

Accepted Answer

The mRNA will not be properly cleaved at the 3' end, resulting in instability and rapid degradation.

Question 5

Which of the following statements about introns and exons is correct?

Accepted Answer

Introns are removed from pre-mRNA during splicing, while exons are joined together to form mature mRNA.

Question 6

Alternative splicing allows for which of the following outcomes?

Accepted Answer

The production of a range of unique but structurally related proteins from the same gene.

Question 7

Which of the following codons serves as the start codon for translation in eukaryotes?

Accepted Answer

$$\mathrm{AUG}$$

Question 8

A researcher mutates the 5' splice site (GU) of an intron in a gene. What is the most likely effect on the mRNA?

Accepted Answer

The intron will be retained in the mature mRNA, potentially disrupting translation.

Question 9

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

Accepted Answer

It forms the core structural and catalytic components of the ribosome.

Question 10

A patient has a genetic disorder caused by a mutation that prevents the addition of the 5' cap to mRNA. Which of the following is a likely consequence?

Accepted Answer

The mRNA will be rapidly degraded by 5' exonucleases and have impaired translation initiation.

Question 11

Which of the following sequences is most likely to be found at the 3' end of a mature eukaryotic mRNA?

Accepted Answer

$$\mathrm{AAAAAA...} ($$poly(A) tail)

Question 12

During translation, which molecule is responsible for matching amino acids to the appropriate codons in the mRNA?

Accepted Answer

tRNA

Question 13

A gene contains the following sequence on its coding strand: 5'-ATG GAA TGA-3'. What is the corresponding mRNA sequence transcribed from this gene?

Accepted Answer

5'-AUG GAA UGA-3'

Question 14

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

Accepted Answer

To add a 5' cap, poly(A) tail, and remove introns, increasing stability and translation efficiency.

Question 15

A mutation in the branch point of an intron would most likely affect which process?

Accepted Answer

Splicing

Question 16

Which of the following is NOT a function of the 5' cap on eukaryotic mRNA?

Accepted Answer

Signaling the site for polyadenylation

Question 17

If a mutation causes the loss of the stop codon in an mRNA, what is the most likely result?

Accepted Answer

Translation will continue into the 3' UTR, producing an abnormally long protein.

Question 18

Which of the following best describes the directionality of translation on an mRNA molecule?

Accepted Answer

Proteins are synthesized from the N-terminus to the C-terminus, reading the mRNA 5' to 3'.

Question 19

A scientist introduces a mutation that prevents the binding of poly(A)-binding proteins (PABPs) to the poly(A) tail. What is the most likely effect on the mRNA?

Accepted Answer

The mRNA will be less stable and more susceptible to degradation.

Question 20

Which of the following best describes the role of enhancer sequences in eukaryotic gene expression?

Accepted Answer

They increase the rate of transcription by binding activator proteins, even when located far from the promoter.

Transcription and Translation: Mechanisms and Regulation in Eukaryotes

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