Question 1

Which of the following best describes the role of a plasmid in the transformation of prokaryotic cells with a eukaryotic gene?

Accepted Answer

A plasmid acts as a vector to carry the eukaryotic gene of interest into the bacterium, allowing for the creation of recombinant DNA (rDNA).

Question 2

During plasmid-based transformation, why is the ampicillin resistance ($amp^r$) gene included in the recombinant plasmid?

Accepted Answer

To allow only bacteria that have taken up the recombinant plasmid to survive on agar plates containing ampicillin.

Question 3

Which of the following is NOT a component of a typical prokaryotic operon?

Accepted Answer

Enhancer

Question 4

In the lac operon, what is the function of allolactose?

Accepted Answer

It acts as an inducer by binding to the repressor and inactivating it, allowing transcription.

Question 5

Which of the following best explains the difference between inducible and repressible operons?

Accepted Answer

Inducible operons are usually off and can be turned on by an inducer, while repressible operons are usually on and can be turned off by a co-repressor.

Question 6

What is the effect of histone acetylation on gene expression in eukaryotic cells?

Accepted Answer

Histone acetylation loosens chromatin structure, making DNA more accessible and stimulating transcription.

Question 7

How does DNA methylation typically affect gene regulation in eukaryotic cells?

Accepted Answer

DNA methylation represses transcription by making DNA less accessible to transcription factors.

Question 8

Which of the following sequences is most likely to be found in the promoter region of a eukaryotic gene?

Accepted Answer

TATA box

Question 9

What is the primary function of activator proteins in eukaryotic gene regulation?

Accepted Answer

They bind to enhancers and increase the rate of transcription by helping assemble the transcription initiation complex.

Question 10

Which of the following best describes the process of RNA interference (RNAi)?

Accepted Answer

Small miRNAs are processed by Dicer, loaded into the argonaute complex, and guide the complex to degrade target mRNA or block its translation, effectively silencing gene expression.

Question 11

A scientist wants to produce human insulin in bacteria. Which of the following steps is necessary for this process?

Accepted Answer

Insert the human insulin gene into a plasmid, transform bacteria with the recombinant plasmid, and select for bacterial clones on ampicillin-containing agar plates.

Question 12

Which of the following is a correct sequence of events in the negative regulation of the trp operon?

Accepted Answer

Tryptophan acts as a co-repressor, binds to the repressor, activates it, and the active repressor binds to the operator to block transcription.

Question 13

Which of the following best describes the function of the operator in a prokaryotic operon?

Accepted Answer

It is a DNA sequence where the repressor protein can bind to regulate transcription of the operon genes.

Question 14

A mutation in the regulatory gene of the lac operon results in a repressor that cannot bind allolactose. What is the most likely outcome?

Accepted Answer

The lac operon will remain off even in the presence of lactose, as the repressor cannot be inactivated.

Question 15

Which of the following is a direct result of the formation of the transcription initiation complex in eukaryotes?

Accepted Answer

RNA polymerase II begins synthesizing mRNA from the DNA template.

Question 16

Which of the following would most likely result from a mutation that deletes the poly-A signal sequence in a eukaryotic gene?

Accepted Answer

The mRNA transcript would not be properly terminated or polyadenylated, leading to instability and rapid degradation.

Question 17

Which of the following best explains why bacterial clones on an agar plate containing ampicillin are considered a pure culture?

Accepted Answer

Each colony arises from a single bacterium that has taken up the recombinant plasmid, making all cells in the colony genetically identical.

Question 18

Which of the following is a function of mediator proteins in eukaryotic transcription?

Accepted Answer

They help transmit signals from activators bound to enhancers to RNA polymerase II at the promoter.

Study Guide: Regulation and Expression of Genes in Prokaryotes and Eukaryotes

Study Guide - Practice Questions

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