Q: During PCR, what is the purpose of the annealing phase?

To allow primers to bind to the template DNA

Q: If $X^2_{exp} < X^2_{crit}$ for a given degree of freedom, what is the correct statistical conclusion?

Fail to reject the null hypothesis

Q: Why is Taq polymerase suitable for PCR?

It is resistant to high temperatures

Q: What is the main function of primers in a PCR reaction?

To determine which segment of DNA is amplified

Question 1

Which phase of the PCR cycle is responsible for separating the hydrogen bonds that hold the strands of the template DNA together?

Accepted Answer

Denaturation phase (94-96°C)

Question 2

Taq DNA polymerase, used in PCR, is derived from which organism?

Accepted Answer

Thermus aquaticus

Question 3

If a chi-square test yields $X^2_{exp} = 6.4$ with $df = 1$, what is the estimated p-value range?

Accepted Answer

$0.05 < p < 0.01$

Question 4

Which two primers would be used to amplify exon 2 of a gene if the exon is flanked by primer sites 2 and 4?

Accepted Answer

Primers 2 and 4

Question 5

PCR is described as an exponential amplification process. If you start with 1 copy of DNA, how many copies will you have after 25 cycles?

Accepted Answer

$2^{25}$

Question 6

What is the standard cutoff for statistical significance in a chi-square test?

Accepted Answer

$p = 0.05$

Question 7

During PCR, what is the purpose of the annealing phase?

Accepted Answer

To allow primers to bind to the template DNA

Question 8

A control PCR product for the HTT gene with 40 CAG repeats is 420 bp long. If an experimental PCR product is 354 bp, how many CAG repeats does it contain? (Each CAG repeat is 3 bp)

Accepted Answer

22 repeats

Question 9

Which of the following is NOT a major application of PCR?

Accepted Answer

Protein synthesis

Question 10

If $X^2_{exp} < X^2_{crit}$ for a given degree of freedom, what is the correct statistical conclusion?

Accepted Answer

Fail to reject the null hypothesis

Question 11

Which step in PCR requires the highest temperature?

Accepted Answer

Denaturation

Question 12

Why is Taq polymerase suitable for PCR?

Accepted Answer

It is resistant to high temperatures

Question 13

A patient’s PCR products for the HTT gene are 354 bp and 462 bp. The control (40 CAG repeats) is 420 bp. How many CAG repeats are in the 462 bp allele?

Accepted Answer

54 repeats

Question 14

Which of the following diseases is associated with trinucleotide (CAG) repeat expansion detected by PCR?

Accepted Answer

Huntington disease

Question 15

What is the main function of primers in a PCR reaction?

Accepted Answer

To determine which segment of DNA is amplified

Question 16

If a chi-square test yields $X^2_{exp} = 3.5$ with $df = 3$, what is the estimated p-value range?

Accepted Answer

$0.5 > p > 0.1$

Question 17

Which of the following best describes the relationship between the number of PCR cycles and the amount of DNA produced?

Accepted Answer

Exponential increase

Question 18

Who invented the PCR technique?

Accepted Answer

Kary Mullis

Question 19

In a forensic investigation, why is PCR preferred for DNA analysis?

Accepted Answer

It can amplify very small amounts of DNA

Question 20

What is the role of the extension phase in PCR?

Accepted Answer

To synthesize new DNA strands by Taq polymerase

Polymerase Chain Reaction (PCR) Sep 17

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