Question 1

Which enzyme is responsible for joining DNA fragments during the creation of recombinant DNA molecules?

Accepted Answer

DNA ligase

Question 2

A restriction enzyme recognizes the sequence $$5'	ext{GAATTC}\ 3'$$ and cuts between G and A. What type of ends does this produce?

Accepted Answer

Sticky ends

Question 3

Which feature of plasmid vectors allows for the easy identification of bacteria that have taken up the plasmid?

Accepted Answer

Selectable marker gene

Question 4

In blue/white screening, what is the expected color of colonies containing recombinant plasmids with an insert disrupting the lacZ gene?

Accepted Answer

White

Question 5

Which vector is commonly used for gene transfer into plant cells?

Accepted Answer

Ti plasmid from Agrobacterium tumefaciens

Question 6

What is the main difference between a genomic library and a cDNA library?

Accepted Answer

Genomic libraries contain all DNA sequences from the genome, while cDNA libraries contain only expressed genes.

Question 7

Which step in PCR is responsible for separating the two DNA strands?

Accepted Answer

Denaturation

Question 8

Why is Taq polymerase used in PCR?

Accepted Answer

It is resistant to high temperatures required for denaturation.

Question 9

Which blotting technique is used to detect specific DNA sequences?

Accepted Answer

Southern blotting

Question 10

A scientist wants to detect the expression of a specific gene at the RNA level. Which technique should they use?

Accepted Answer

Northern blotting

Question 11

Which of the following is a limitation of PCR?

Accepted Answer

It is limited by the size of the DNA fragment that can be amplified.

Question 12

What is the purpose of the poly-A tail in the creation of a cDNA library?

Accepted Answer

It allows the use of oligo(dT) primers to selectively reverse transcribe mRNA.

Question 13

Which equation best describes the exponential amplification of DNA during PCR?

Accepted Answer

$$N = N_0$ 	imes 2^n$$

Question 14

Which of the following is NOT a feature of a typical plasmid cloning vector?

Accepted Answer

Telomere sequence

Question 15

In CRISPR-Cas genome editing, what is the function of the single guide RNA (sgRNA)?

Accepted Answer

It guides Cas9 to the target DNA sequence for cleavage.

Question 16

After Cas9 creates a double-stranded break in DNA, which repair mechanism can introduce insertions or deletions?

Accepted Answer

Non-homologous end joining (NHEJ)

Question 17

Which of the following is a potential limitation of CRISPR-Cas genome editing?

Accepted Answer

sgRNA may direct Cas9 to off-target sites with similar sequences.

Question 18

Which of the following best describes the process of creating a genomic library?

Accepted Answer

Isolate genomic DNA, digest with restriction enzymes, ligate fragments into vectors, and transform bacteria.

Question 19

Which enzyme is used to synthesize cDNA from mRNA templates?

Accepted Answer

Reverse transcriptase

Recombinant DNA Technology: Principles and Applications

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