Question 1

Which of the following is NOT a required component for a standard Polymerase Chain Reaction (PCR)?

Accepted Answer

Ribosomes

Question 2

During the PCR process, what is the primary purpose of the denaturation step?

Accepted Answer

To separate the DNA strands by breaking hydrogen bonds

Question 3

A researcher wants to amplify a specific gene from a bacterial chromosome. Which step ensures that only the target gene is amplified during PCR?

Accepted Answer

Designing primers complementary to sequences flanking the gene

Question 4

Which of the following best describes the role of dideoxynucleotides (ddNTPs) in Sanger DNA sequencing?

Accepted Answer

They terminate DNA strand elongation due to the lack of a 3' hydroxyl group

Question 5

In a real-time PCR (qPCR) experiment, what is being measured to quantify the amount of DNA template present?

Accepted Answer

The change in fluorescence emitted by detector molecules

Question 6

A patient is tested for COVID-19 using a PCR-based method. Which variation of PCR is most likely used to detect viral RNA?

Accepted Answer

Reverse transcriptase PCR (RT-PCR)

Question 7

Which of the following equations correctly represents the exponential amplification of DNA during PCR, where $$n is $$the number of cycles and $$N_0 is $$the initial number of DNA molecules?

Accepted Answer

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

Question 8

Why is a thermostable DNA polymerase, such as Taq polymerase, essential for PCR?

Accepted Answer

It remains active after repeated heating cycles required for DNA denaturation

Question 9

A scientist is comparing the DNA sequences of two related species to study their evolutionary relationship. Which technique would be most appropriate for this purpose?

Accepted Answer

DNA sequencing

Question 10

In Sanger sequencing, why are both dNTPs and ddNTPs included in the reaction mixture?

Accepted Answer

dNTPs allow normal DNA synthesis, while ddNTPs randomly terminate synthesis to generate fragments of varying lengths

Question 11

A forensic scientist needs to identify a suspect by comparing DNA samples from a crime scene and a suspect. Which molecular technique would be most appropriate for this analysis?

Accepted Answer

Polymerase Chain Reaction (PCR) followed by gel electrophoresis

Question 12

Which of the following best explains why PCR can be used to detect genetic diseases caused by specific mutations?

Accepted Answer

Primers can be designed to specifically amplify regions containing the mutation, allowing detection

Question 13

Which step in the PCR cycle is responsible for the specificity of the DNA amplification?

Accepted Answer

Annealing

Question 14

A researcher is using RT-PCR to measure gene expression levels in cancer cells. What is the first step in this process?

Accepted Answer

Isolating RNA from the cells

Question 15

Which of the following statements about dideoxynucleotides (ddNTPs) is correct?

Accepted Answer

They lack a 3' hydroxyl group, preventing further elongation of the DNA strand

Question 16

A student is analyzing the results of an automated DNA sequencing run. The output shows a series of colored peaks. What do these peaks represent?

Accepted Answer

The order of nucleotides in the DNA sequence

Question 17

Which of the following best describes the function of oligonucleotide primers in PCR?

Accepted Answer

They provide a starting point for DNA polymerase to extend the DNA strand

Question 18

A laboratory technician is using gel electrophoresis to analyze PCR products. What property of DNA fragments allows them to be separated by this technique?

Accepted Answer

Their length (size)

Question 19

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

Accepted Answer

Identifying genetic mutations associated with inherited diseases

Question 20

A scientist wants to compare the expression levels of a specific gene in two different tissue samples. Which technique should they use?

Accepted Answer

Reverse transcriptase PCR (RT-PCR)

Molecular Techniques in Genetics: PCR and DNA Sequencing

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