$$\text{Single gene} \rightarrow \text{Single pre-mRNA} \rightarrow \text{Multiple mature mRNAs} \rightarrow \text{Multiple proteins}$$

Question 1

Which of the following best describes the process of alternative splicing in eukaryotes?

Accepted Answer

A single pre-mRNA can be spliced in multiple ways, resulting in multiple mature mRNAs and different proteins.

Question 2

In the context of gene regulation, what is the primary function of microRNA (miRNA) in eukaryotic cells?

Accepted Answer

miRNA binds to mRNA and either degrades it or inhibits its translation.

Question 3

Which equation best represents the relationship between a single gene, pre-mRNA, and protein diversity due to alternative splicing?

Accepted Answer

$$	ext{Single gene} ightarrow 	ext{Single pre-mRNA} ightarrow 	ext{Multiple mature mRNAs} ightarrow 	ext{Multiple proteins}$$

Question 4

What is the role of snRNPs in the process of RNA splicing?

Accepted Answer

snRNPs bind to introns and facilitate their removal from the pre-mRNA.

Question 5

A mutation in the regulatory proteins that control splicing could result in:

Accepted Answer

The production of only one type of protein from a gene that normally produces several.

Question 6

Which of the following is a major difference between gene expression in bacteria and eukaryotes?

Accepted Answer

Eukaryotes use extensive RNA processing, including alternative splicing, while bacteria rarely do.

Question 7

In the process of RNA interference, what happens if the miRNA bound to RISC is a perfect match to the target mRNA?

Accepted Answer

The mRNA is cut and degraded, preventing translation.

Question 8

Which post-translational modification is responsible for targeting proteins for destruction in eukaryotic cells?

Accepted Answer

Addition of ubiquitin molecules.

Question 9

A cell receives a signal to differentiate into a muscle cell. Which mechanism ensures that the correct form of tropomyosin is produced?

Accepted Answer

Alternative splicing regulated by cell-specific splicing proteins.

Question 10

Which of the following best explains why a single fruit fly gene can produce up to 38,000 different mRNAs?

Accepted Answer

The gene contains a large number of exons that can be combined in many ways through alternative splicing.

Question 11

Which of the following equations represents the effect of miRNA on mRNA stability and translation?

Accepted Answer

$$	ext{miRNA} + 	ext{mRNA} ightarrow 	ext{RISC complex} ightarrow 	ext{mRNA degradation or translation inhibition}$$

Question 12

Which statement about gene organization in bacteria is correct?

Accepted Answer

Genes coding for proteins in the same pathway are grouped into operons and regulated as a single unit.

Question 13

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

Accepted Answer

Alternative splicing of pre-mRNA.

Question 14

What is the effect of allosteric regulation on enzyme activity?

Accepted Answer

It changes the shape of the enzyme, inhibiting its activity.

Question 15

Which of the following is a key difference in transcriptional regulation between bacteria and eukaryotes?

Accepted Answer

Eukaryotes use activators, repressors, and mediator proteins that interact with regulatory sequences both close to and far from the promoter.

Question 16

Which process is illustrated by the equation $$	ext{Protein} + 	ext{Ubiquitin} ightarrow 	ext{Proteasome} ightarrow 	ext{Small peptides}$$?

Accepted Answer

Targeted protein destruction by the proteasome.

Question 17

Which of the following is a consequence of RNA interference in eukaryotic cells?

Accepted Answer

Decreased activity and lifespan of many mRNAs.

Question 18

Which of the following best describes the role of kinases and phosphatases in post-translational control?

Accepted Answer

Kinases phosphorylate proteins, activating or deactivating them; phosphatases remove phosphate groups, reversing the effect.

Question 19

Which of the following is a real-world example of alternative splicing affecting protein function?

Accepted Answer

The tropomyosin gene produces different protein isoforms in skeletal and smooth muscle cells, each with unique functions.

CH. 19 p. 2- Post-Transcriptional Control and Comparison of Gene Expression in Bacteria and Eukaryotes

Study Guide - Practice Questions