Question 1

Which of the following best describes the process of alternative splicing in eukaryotic cells?

Accepted Answer

Introns are removed and different combinations of exons are joined to produce multiple mRNAs from one gene.

Question 2

A mutation prevents the formation of the spliceosome in a human cell. What is the most likely consequence?

Accepted Answer

Pre-mRNA will not be properly processed, resulting in retention of introns and potentially nonfunctional proteins.

Question 3

Which of the following is a direct outcome of miRNA binding to its target mRNA in the cytoplasm?

Accepted Answer

Cleavage and degradation of the mRNA or inhibition of its translation.

Question 4

A researcher finds that a specific mRNA is present in high amounts in a cell, but the corresponding protein is not detected. Which regulatory mechanism is most likely responsible?

Accepted Answer

Translational repression by miRNA or regulatory proteins.

Question 5

Which of the following statements correctly compares gene expression in prokaryotes and eukaryotes?

Accepted Answer

Prokaryotes lack chromatin and do not perform alternative splicing.

Question 6

What is the role of ubiquitin in post-translational control of gene expression?

Accepted Answer

It tags unwanted or damaged proteins for degradation by the proteasome.

Question 7

During a viral infection, cells often phosphorylate translation factors. What is the primary effect of this modification?

Accepted Answer

It pauses all translation, protecting the cell from viral replication.

Question 8

Which of the following is NOT a mechanism of post-translational control in eukaryotic cells?

Accepted Answer

Alternative splicing of pre-mRNA.

Question 9

A cell type produces two different proteins from the same gene, depending on which exons are included in the final mRNA. This phenomenon is best explained by:

Accepted Answer

Alternative splicing.

Question 10

Which of the following best describes the function of the RISC protein complex in RNA interference?

Accepted Answer

It guides miRNA to complementary mRNA and either degrades the mRNA or blocks its translation.

Question 11

If a mutation prevents the addition of a poly-A tail to pre-mRNA, what is the most likely consequence for gene expression?

Accepted Answer

The mRNA will be less stable and degraded quickly, reducing protein production.

Question 12

Which equation best represents the relationship between gene expression and mRNA stability?

Accepted Answer

$	ext{Protein output} \propto 	ext{mRNA stability}$

Question 13

Which of the following is a real-world example of alternative splicing producing cell-type-specific proteins?

Accepted Answer

Thyroid cells produce calcitonin, while hypothalamus cells produce CGRP from the same gene.

Question 14

Which of the following statements about the proteasome is correct?

Accepted Answer

It recognizes polyubiquitinated proteins and degrades them into small peptides.

Question 15

A scientist deletes a DNA sequence outside the protein-coding region of a gene and observes decreased transcription. This deleted sequence most likely functions as a(n):

Accepted Answer

Promoter-proximal element.

Question 16

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

Accepted Answer

Eukaryotes remove introns and splice exons; prokaryotes do not perform splicing.

Question 17

Which of the following regulatory elements is responsible for increasing the rate of transcription by binding to activator proteins?

Accepted Answer

Enhancer.

Question 18

Which process allows eukaryotic cells to rapidly decrease the amount of a specific protein in response to changing conditions?

Accepted Answer

Targeted destruction of proteins by the ubiquitin-proteasome pathway.

Question 19

Which of the following is a consequence of translational control being faster than transcriptional control?

Accepted Answer

Cells can quickly adjust protein levels in response to stress because mRNA is already present.

Eukaryotic Gene Expression: Regulation, Alternative Splicing, and Post-Translational Control

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