Question 1

Which of the following best describes the function of restriction enzymes in recombinant DNA technology?

Accepted Answer

They cut DNA at specific recognition sequences, producing fragments with sticky or blunt ends.

Question 2

A researcher wants to clone a gene into a plasmid vector and identify bacteria that have taken up recombinant plasmids using blue-white screening. Which colonies should the researcher select for further analysis?

Accepted Answer

Ampicillin resistant, white colonies

Question 3

Which of the following is NOT a necessary feature of a good cloning vector?

Accepted Answer

The ability to carry DNA fragments of up to 200 kb

Question 4

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

Accepted Answer

DNA ligase

Question 5

A DNA fragment is inserted into the multiple cloning site of a plasmid vector, disrupting the lacZ gene. When plated on X-gal, what color will the resulting bacterial colonies be?

Accepted Answer

White

Question 6

Which of the following statements about palindromic sequences recognized by restriction enzymes is correct?

Accepted Answer

They are sequences that read the same on both strands in the 5' to 3' direction.

Question 7

Which of the following best explains why PCR (polymerase chain reaction) is a powerful tool in forensic science?

Accepted Answer

It can amplify specific DNA sequences from very small or degraded samples.

Question 8

A scientist is constructing a cDNA library from liver cells. Which enzyme is essential for synthesizing the first DNA strand from mRNA?

Accepted Answer

Reverse transcriptase

Question 9

Which of the following is a limitation of PCR?

Accepted Answer

It cannot amplify long segments of DNA.

Question 10

In agarose gel electrophoresis, which DNA fragments migrate the farthest from the wells?

Accepted Answer

The smallest fragments

Question 11

Which of the following best describes the Southern blot technique?

Accepted Answer

It separates DNA fragments by size, transfers them to a membrane, and detects specific sequences with a labeled probe.

Question 12

Which of the following is a unique feature of expression vectors compared to standard cloning vectors?

Accepted Answer

They ensure mRNA expression of the cloned gene to produce protein in the host cell.

Question 13

Which repair mechanism is used by eukaryotic cells after a double-stranded break is introduced by CRISPR-Cas9, and can result in insertions or deletions (indels)?

Accepted Answer

Nonhomologous end-joining (NHEJ)

Question 14

Which of the following is a critical requirement for the design of PCR primers?

Accepted Answer

They must be complementary to the 5' and 3' ends of the target sequence.

Question 15

Which of the following statements about Sanger sequencing is correct?

Accepted Answer

It uses dideoxynucleotides to terminate DNA synthesis at specific bases.

Question 16

A genomic library constructed from eukaryotic DNA will contain which of the following?

Accepted Answer

Both coding and noncoding sequences, including introns

Question 17

Which of the following is a potential problem when using CRISPR-Cas9 for genome editing?

Accepted Answer

Cas9 can cut at off-target sites due to imperfect sgRNA specificity.

Question 18

Which of the following best describes the purpose of a probe in library screening?

Accepted Answer

To hybridize with and identify clones containing a specific gene of interest

Question 19

Which of the following statements about cDNA libraries is correct?

Accepted Answer

They represent only the genes expressed as mRNA at the time of library construction.

Question 20

Which of the following is a real-world application of quantitative real-time PCR (qPCR)?

Accepted Answer

Quantifying the amount of a specific DNA or RNA sequence in a clinical sample

Chapter 17: Recombinant DNA Technology – Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard