Question 1

Which of the following best describes the main advantage of using PCR (polymerase chain reaction) in molecular genetics research?

Accepted Answer

It enables exponential amplification of specific DNA sequences from minimal starting material.

Question 2

A researcher wants to clone a human gene into a bacterial plasmid. Which sequence of steps is most appropriate for this process?

Accepted Answer

Ligate the gene into the plasmid, transform bacteria, select for antibiotic resistance.

Question 3

Which enzyme is responsible for joining DNA fragments with complementary sticky ends during recombinant DNA technology?

Accepted Answer

DNA ligase

Question 4

In Sanger sequencing, what is the role of dideoxynucleotides (ddNTPs)?

Accepted Answer

They terminate DNA strand elongation at specific bases.

Question 5

A scientist is using qPCR to quantify viral RNA in patient samples. Which parameter is most directly used to estimate the initial amount of template?

Accepted Answer

The Ct (threshold cycle) value

Question 6

Which of the following statements about restriction enzymes is CORRECT?

Accepted Answer

They cut DNA at specific palindromic sequences, generating sticky or blunt ends.

Question 7

A cDNA library differs from a genomic DNA library in that a cDNA library:

Accepted Answer

Contains only the coding sequences (exons) of expressed genes.

Question 8

Which of the following best explains why Taq polymerase is used in PCR?

Accepted Answer

It is resistant to high temperatures required for DNA denaturation.

Question 9

A researcher wants to knock out a gene in mice to study its function. Which technique is most appropriate?

Accepted Answer

Homologous recombination in embryonic stem cells

Question 10

Which of the following is a key feature of next-generation sequencing (NGS) compared to Sanger sequencing?

Accepted Answer

It allows massively parallel sequencing of millions of DNA fragments simultaneously.

Question 11

Which of the following is a real-world application of recombinant DNA technology?

Accepted Answer

Production of recombinant human insulin for diabetes therapy

Question 12

Which of the following best describes the function of guide RNA in the CRISPR-Cas9 system?

Accepted Answer

It directs the Cas9 nuclease to a specific DNA sequence for targeted cleavage.

Question 13

A scientist wants to express a human protein in yeast cells. Which of the following vectors is most suitable?

Accepted Answer

Yeast artificial chromosome (YAC)

Question 14

Which of the following equations correctly represents the theoretical amplification of DNA after n cycles of PCR, starting from a single molecule?

Accepted Answer

$$N = 2^n$$

Question 15

In the context of molecular genetics, what is the main purpose of using a selectable marker gene in a cloning vector?

Accepted Answer

To identify host cells that have successfully taken up the vector

Question 16

Which of the following statements about CRISPR-Cas9 genome editing is TRUE?

Accepted Answer

It uses an RNA guide to target specific DNA sequences for editing.

Question 17

A patient sample is tested for SARS-CoV-2 using RT-qPCR. Which step is essential before PCR amplification can occur?

Accepted Answer

Reverse transcription of viral RNA to cDNA

Question 18

Which of the following best explains why a cDNA library is useful for expressing eukaryotic genes in bacteria?

Accepted Answer

It contains only exons, so bacterial cells can translate the mRNA without needing to remove introns.

Question 19

Which of the following is a key difference between Southern blotting and Northern blotting?

Accepted Answer

Southern blotting analyzes DNA, while Northern blotting analyzes RNA.

Molecular Methods in Genetic Research: Techniques and Applications

Study Guide - Practice Questions