$$\text{Vector DNA} + \text{Target gene in genome} \rightarrow \text{Recombined gene with inserted DNA}$$

Question 1

Which of the following best describes the role of regulatory transcription factors (RTFs) in gene expression?

Accepted Answer

RTFs regulate the rate of transcription by binding to regulatory elements, acting as activators or repressors.

Question 2

Which chromatin feature is most likely to prevent regulatory transcription factors from binding and initiating transcription?

Accepted Answer

Closed chromatin conformation

Question 3

A scientist wants to express a eukaryotic gene in bacteria to produce a protein. Which DNA source should they use to avoid issues with introns?

Accepted Answer

cDNA synthesized from mRNA using reverse transcriptase

Question 4

Which of the following is a key feature of plasmid vectors used in molecular cloning?

Accepted Answer

They contain a selectable marker such as AmpR for antibiotic resistance.

Question 5

What is the primary function of restriction enzymes in recombinant DNA technology?

Accepted Answer

To cleave DNA at specific sequences, generating fragments with sticky or blunt ends.

Question 6

In blue-white selection, what does the appearance of white colonies on X-gal plates indicate?

Accepted Answer

The colony contains a plasmid with an inserted DNA fragment disrupting lacZ.

Question 7

Which molecular mechanism is NOT considered part of epigenetic regulation?

Accepted Answer

Mutation in the DNA sequence

Question 8

What is the role of the Dicer enzyme in gene silencing by interfering RNAs?

Accepted Answer

Dicer cleaves double-stranded RNA into fragments of about 25 nucleotides.

Question 9

After Dicer processes siRNA or miRNA, what happens to the resulting fragments in the cell?

Accepted Answer

They are loaded onto the RISC complex and guide mRNA degradation or translation block.

Question 10

Which equation best represents the process of homologous recombination used in gene targeting in embryonic stem cells?

Accepted Answer

$$	ext{Vector DNA} + 	ext{Target gene in genome} ightarrow 	ext{Recombined gene with inserted DNA}$$

Question 11

Which step is essential for creating a transgenic corn plant resistant to insects using the Bt gene?

Accepted Answer

Amplifying the Bt gene from Bacillus thuringiensis and a corn promoter, then ligating them into a vector.

Question 12

Which of the following statements about Gibson Assembly is correct?

Accepted Answer

Gibson Assembly uses a 5’ exonuclease, polymerase, and ligase to join DNA fragments with overlapping ends.

Question 13

Which of the following is a limitation of extrachromosomal arrays in C. elegans transgenics?

Accepted Answer

They often result in overexpression in somatic tissues and silencing in the germline.

Question 14

In Drosophila, what is the function of the transposase-coding region in the P element?

Accepted Answer

It mobilizes the P element, enabling insertion of the gene of interest into the genome.

Question 15

Which technique is used to force mouse embryonic stem cells to take up exogenous DNA during germline transformation?

Accepted Answer

Electroporation

Question 16

What is the main advantage of using cDNA instead of genomic DNA for cloning eukaryotic genes?

Accepted Answer

cDNA lacks introns, allowing for proper expression in prokaryotic hosts.

Question 17

Which of the following best describes the process of reproductive cloning as used to produce Dolly the sheep?

Accepted Answer

A somatic cell nucleus is fused with an enucleated egg, and the embryo is implanted into a surrogate ewe.

Question 18

Which equation represents the action of DNA ligase in recombinant DNA technology?

Accepted Answer

$$	ext{DNA fragments with sticky ends} \xrightarrow{	ext{DNA ligase}} 	ext{Recombinant DNA molecule}$$

Molecular Cloning, Transgenic Technology, and Gene Regulation: Study Notes for Genetics

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