Immunological Diagnostic 2: PCR And Quick Tests
- 1.
The Polymerase Chain Reaction results is exponential multiplication of the DNA chain
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The statement is true because the Polymerase Chain Reaction (PCR) is a technique used to amplify a specific segment of DNA. It involves a series of temperature cycles that allow for the exponential multiplication of the DNA chain. This process starts with denaturation, where the DNA strands separate, followed by annealing, where primers bind to the target DNA, and finally extension, where DNA polymerase synthesizes new DNA strands. This cycle is repeated multiple times, resulting in a significant increase in the number of DNA copies, making PCR a powerful tool in molecular biology and genetic research.Rate this question:
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- 2.
The Polymerase Chain Reaction is reliant on the action of primers (nucleotide sequences which act to amplify the translation of a certain gene)
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The statement is true because the Polymerase Chain Reaction (PCR) does rely on the action of primers. Primers are short nucleotide sequences that bind to the DNA template and initiate the replication process. They act as a starting point for DNA synthesis and help amplify the specific gene of interest. Without primers, PCR would not be able to selectively amplify the target gene. Therefore, the correct answer is true.Rate this question:
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- 3.
Taq polymerase is stable at 142oC
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
*Stable at 96oC; ideal as it can survive heating processRate this question:
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- 4.
DNA primers are non-specific to genes
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
DNA primers are specific to genes. Primers are short DNA sequences that are complementary to specific regions of the target gene. They are designed to bind to the specific DNA sequence of the gene of interest, allowing for amplification of that specific gene during PCR (Polymerase Chain Reaction) or other DNA sequencing techniques. Therefore, the statement that DNA primers are non-specific to genes is incorrect.Rate this question:
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- 5.
Taq polymerases activity is dependant on temperature
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Taq polymerase is a DNA polymerase enzyme commonly used in the polymerase chain reaction (PCR). It is derived from the bacterium Thermus aquaticus, which is found in hot springs. Taq polymerase is known for its ability to withstand high temperatures, making it ideal for PCR reactions that require high temperatures for DNA replication. Therefore, the activity of Taq polymerase is indeed dependent on temperature, as it functions optimally at temperatures around 70-80 degrees Celsius.Rate this question:
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- 6.
DNA primers are 25 - 35 nucleotides long
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
DNA primers are typically 25-35 nucleotides long because this length allows for efficient and specific binding to the target DNA sequence during the polymerase chain reaction (PCR) process. Shorter primers may not provide enough specificity, leading to non-specific amplification, while longer primers may hinder the efficiency of the PCR reaction. Therefore, the optimal length range for DNA primers is 25-35 nucleotides.Rate this question:
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- 7.
DNA primers bind to the sense strand of DNA
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
*binds to antisenseRate this question:
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- 8.
Which is the first step in the polymerase chain reaction?
- A.
DNA is heated to around 80oC, causing the strands to come apart
- B.
Viral gene translation is amplified
- C.
As the mixture cools, Taq polymerase starts to work
- D.
Sites for Taq polymerase on DNA are exposed
- E.
Heating and cooling process is repeated 30 - 40 times
Correct Answer
A. DNA is heated to around 80oC, causing the strands to come apartExplanation
In the polymerase chain reaction, the first step is to heat the DNA to around 80oC. This high temperature causes the DNA strands to separate or come apart, a process known as denaturation. This is necessary because the DNA strands need to be separated in order for the PCR reaction to proceed. Once the strands are separated, the other steps of the PCR reaction can take place, such as primer annealing, DNA synthesis, and amplification. The heating step is crucial in initiating the PCR process and allowing for the amplification of specific DNA sequences.Rate this question:
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- 9.
Which is the second step in the polymerase chain reaction?
- A.
DNA is heated to around 80oC, causing the strands to come apart
- B.
Viral gene translation is amplified
- C.
As the mixture cools, Taq polymerase starts to work
- D.
Sites for Taq polymerase on DNA are exposed
- E.
Heating and cooling process is repeated 30 - 40 times
Correct Answer
D. Sites for Taq polymerase on DNA are exposedExplanation
In the polymerase chain reaction, the second step is when the sites for Taq polymerase on DNA are exposed. This occurs after the DNA is heated to around 80°C, causing the strands to come apart. Once the strands separate, the sites for Taq polymerase become accessible for the enzyme to bind and initiate DNA replication. This step is crucial for the amplification of the target DNA sequence in the PCR process.Rate this question:
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- 10.
Which is the third step in the polymerase chain reaction?
- A.
DNA is heated to around 80oC, causing the strands to come apart
- B.
Viral gene translation is amplified
- C.
As the mixture cools, Taq polymerase starts to work
- D.
Sites for Taq polymerase on DNA are exposed
- E.
Heating and cooling process is repeated 30 - 40 times
Correct Answer
C. As the mixture cools, Taq polymerase starts to work -
- 11.
Which is the fourth step in the polymerase chain reaction?
- A.
DNA is heated to around 80oC, causing the strands to come apart
- B.
Viral gene translation is amplified
- C.
As the mixture cools, Taq polymerase starts to work
- D.
Sites for Taq polymerase on DNA are exposed
- E.
Heating and cooling process is repeated 30 - 40 times
Correct Answer
B. Viral gene translation is amplified -
- 12.
Which is the fifth step in the polymerase chain reaction?
- A.
DNA is heated to around 80oC, causing the strands to come apart
- B.
Viral gene translation is amplified
- C.
As the mixture cools, Taq polymerase starts to work
- D.
Sites for Taq polymerase on DNA are exposed
- E.
Heating and cooling process is repeated 30 - 40 times
Correct Answer
E. Heating and cooling process is repeated 30 - 40 times -
- 13.
What gel is typically used during electrophoresis?
- A.
Agar gel
- B.
Hydro gel
- C.
Sucarose gel
- D.
Agarose gel
Correct Answer
D. Agarose gelExplanation
Agarose gel is typically used during electrophoresis because it provides a stable matrix for separating DNA, RNA, or proteins based on their size and charge. Agarose is a polysaccharide derived from seaweed and forms a porous gel when mixed with a buffer solution. This gel allows molecules to migrate through it when an electric current is applied, with smaller molecules moving faster and further than larger ones. Agarose gel is commonly used in molecular biology laboratories for DNA and RNA analysis, as well as protein separation.Rate this question:
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- 14.
What is the principles by which electrophoresis of DNA works?
- A.
DNA is negatively charged, hence it moves toward the positively charged area; larger DNA migrates at a rate faster than smaller DNA
- B.
DNA is positively charged, hence it moves toward the negatively charged area; larger DNA migrates at a rate slower than smaller DNA
- C.
DNA is negatively charged, hence it moves toward the positively charged area; larger DNA migrates at a rate slower than smaller DNA
- D.
DNA is positively charged, hence it moves toward the negatively charged area; larger DNA migrates at a rate faster than smaller DNA
Correct Answer
C. DNA is negatively charged, hence it moves toward the positively charged area; larger DNA migrates at a rate slower than smaller DNAExplanation
DNA is negatively charged due to the phosphate groups in its backbone, which carry a negative charge. In electrophoresis, an electric field is applied, causing the DNA molecules to move towards the positive electrode. Since larger DNA molecules experience more resistance as they move through the gel matrix, they migrate at a slower rate compared to smaller DNA molecules. Therefore, the correct answer is that DNA is negatively charged, hence it moves toward the positively charged area; larger DNA migrates at a rate slower than smaller DNA.Rate this question:
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- 15.
Which of the following is not an advantage of PCT?
- A.
Does not give false positive results
- B.
Highly sensitive
- C.
Can be performed soon after infection
- D.
Does not rely on antibody production
Correct Answer
A. Does not give false positive resultsExplanation
PCT, or procalcitonin, is a biomarker used to detect bacterial infections. It has several advantages, including high sensitivity, the ability to be performed soon after infection, and not relying on antibody production. However, one disadvantage of PCT is that it can give false positive results, meaning it may indicate the presence of a bacterial infection when none is actually present.Rate this question:
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- 16.
Which of the following is not a disadvantage of PCT?
- A.
Can be too sensitive; a small amount of contamination can give a +ve signal
- B.
Expensive to perform
- C.
Quick to perform; can easily be automated
- D.
Need to extract DNA
Correct Answer
C. Quick to perform; can easily be automatedExplanation
The given answer states that "Quick to perform; can easily be automated" is not a disadvantage of PCT. This means that PCT is advantageous in terms of being quick to perform and easily automated. This implies that PCT does not require a significant amount of time or manual effort to be performed, and it can be easily integrated into automated systems, which makes it efficient and convenient to use.Rate this question:
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- 17.
How long does it take for a PCT to be possible post-infection?
- A.
1 week
- B.
2 weeks
- C.
3 weeks
- D.
4 weeks
- E.
5 weeks
- F.
6 weeks
Correct Answer
C. 3 weeksExplanation
The correct answer is 3 weeks. This suggests that it takes approximately three weeks for a post-infection PCT (Presumptive Coliform Test) to be possible. This could mean that after three weeks, the presence of coliform bacteria can be accurately detected in water samples, indicating a possible contamination.Rate this question:
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- 18.
What is the purpose of reverse transciptases in RT-PCT?
- A.
Allows RNA signal to be amplified
- B.
Converts viral DNA into RNA
- C.
Converts RNA to DNA as it is unstable (to heating process???)
- D.
Something
Correct Answer
C. Converts RNA to DNA as it is unstable (to heating process???)Explanation
Reverse transcriptases are enzymes that convert RNA into DNA. In RT-PCR (Reverse Transcription Polymerase Chain Reaction), the purpose of reverse transcriptases is to convert the RNA template into complementary DNA (cDNA), as RNA is less stable and prone to degradation. The cDNA can then be amplified and analyzed using PCR. This process allows for the detection and quantification of RNA molecules, enabling the amplification of RNA signals.Rate this question:
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- 19.
HIV is not a retrovirus or RNA virus, therefore PCT is used as opposed to RT-PCT when testing for it.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
HIV is a retrovirusRate this question:
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Current Version
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Mar 21, 2023Quiz Edited by
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Nov 20, 2012Quiz Created by
ILovePharmacy
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