Quiz Online 6 Chapter 7 The Polymerase Chain Reaction

PCR is a widely used technique in molecular biology that allows for the amplification of specific DNA sequences. It involves a series of temperature cycles that allow for the denaturation, annealing, and extension of DNA strands. By using specific primers that target the desired DNA sequence, PCR can selectively amplify that region, allowing for further analysis or manipulation of the DNA. Therefore, the statement "Polymerase chain reaction (PCR) is a method for the selective amplification of DNA sequences" is true.

After completing the PCR process, agarose gel electrophoresis is used to analyze the amplified DNA fragments. Agarose gel electrophoresis is a technique that separates DNA fragments based on their size. The DNA samples are loaded onto a gel and an electric current is applied, causing the DNA fragments to migrate through the gel. Smaller fragments move faster and travel further, while larger fragments move slower and stay closer to the loading well. By comparing the migration pattern of the DNA samples to a DNA ladder of known sizes, the size of the amplified fragments can be determined. Therefore, the statement is true.

The given statement is true because the typical temperature profile of PCR (Polymerase Chain Reaction) steps involves denaturation at 95°C, primer annealing at 55°C, and extension by Taq polymerase at 72°C. This temperature profile allows for the denaturation of double-stranded DNA, the annealing of primers to the DNA template, and the extension of the primers by Taq polymerase to synthesize new DNA strands. Therefore, the given answer is true.

RT-PCR stands for Reverse Transcriptase Polymerase Chain Reaction. It is a technique used to amplify and detect specific RNA sequences. In RT-PCR, a cDNA copy of mRNA is first synthesized using reverse transcriptase enzyme. This cDNA is then amplified using PCR to obtain multiple copies of the target sequence. Therefore, the given statement that RT-PCR involves the synthesis of a cDNA copy of mRNA and its subsequent amplification using PCR is true.

The polymerase chain reaction (PCR) is a technique used in molecular biology to amplify a specific DNA sequence. By using specific primers that are complementary to the target sequence, PCR can selectively amplify and clone the desired DNA fragment. This allows for the production of multiple copies of the target sequence, making it easier to study and manipulate in the laboratory. Therefore, the statement that PCR can be used to clone specific sequences is true.

The given statement is true. Random amplified polymorphic DNA (RAPD) is a PCR-based method used for DNA profiling. It involves amplifying specific DNA sequences using random primers. This technique is commonly used in genetic research and forensic analysis to compare DNA samples and identify genetic variations.

Thermostable DNA polymerases, like Taq polymerase, are able to withstand high temperatures without denaturing. This allows for the automation of the polymerase chain reaction (PCR) process, as there is no need to add fresh polymerase after each denaturation stage. This is because the thermostable polymerase remains active throughout the entire PCR cycle, making the statement TRUE.

PCR (Polymerase Chain Reaction) is a laboratory technique used to amplify a specific DNA sequence. It requires a DNA polymerase enzyme to catalyze the synthesis of new DNA strands. In this case, the DNA polymerase used in PCR is purified from the thermophilic bacterium Thermus aquaticus, which is known to inhabit hot springs. This is because PCR requires high temperatures for the denaturation step, and the DNA polymerase from Thermus aquaticus is heat-stable and can withstand the high temperatures required for PCR. Therefore, the statement is true.

PCR stands for Polymerase Chain Reaction, which is a technique used to amplify specific DNA sequences. In this context, the question is stating that PCR can be used to clone genes from one organism by using priming sequences from another organism, as long as some sequence data for the gene is available. This is true because PCR requires primers, which are short DNA sequences that bind to the target DNA and serve as starting points for DNA replication. These primers can be designed based on known sequence data from a different organism, allowing for the cloning of genes from one organism using priming sequences from another.

A thermal cycler is the correct answer because it is a heating/cooling system used for PCR applications. It allows for the denaturation, primer binding, and extension cycles to be programmed and automated, making it an essential tool in PCR experiments.

Nested PCR does indeed involve using two sets of primers. In this technique, a first round of PCR is performed using a set of outer primers, which amplifies the target DNA sequence. Then, a second round of PCR is performed using a set of inner primers, which amplify a smaller region within the first PCR product. This nested approach increases the specificity and sensitivity of the PCR reaction, as it reduces non-specific amplification and enhances the detection of low abundance target sequences. Therefore, the statement "Nested PCR involves using two sets of primers" is correct.

AFLP polymorphism is a method used for genome analysis that involves PCR amplification of restriction digests of genomic DNA. This technique allows for the identification of genetic variations and polymorphisms within a genome. Therefore, the statement "Amplified fragment length (AFLP) polymorphism is genome analysis by PCR of restriction digests of genomic DNA" is true.

RT-PCR (Reverse Transcription Polymerase Chain Reaction) is a technique used to amplify and detect specific RNA molecules, including mRNA. It converts the RNA into complementary DNA (cDNA) using reverse transcriptase enzyme, which is then amplified using PCR. By measuring the amount of amplified cDNA, RT-PCR can determine the quantity of mRNA present in a sample. Therefore, the statement that RT-PCR is used in determining the amount of mRNA in a sample is true.

The explanation for the given correct answer is that the key requirements for the PCR (Polymerase Chain Reaction) are indeed a DNA template, a pair of suitable oligonucleotide primers, and a DNA polymerase. These components are essential for the amplification of DNA in the PCR process. The DNA template serves as the starting material, the primers bind to specific regions on the DNA template to initiate replication, and the DNA polymerase enzyme synthesizes new DNA strands using the primers as a starting point. Therefore, all three components are necessary for the successful execution of PCR.

The statement is true because in order for the primers to amplify the target sequence, they need to be positioned on either side of the target sequence. This allows the primers to bind to the DNA and initiate the amplification process. If the primers do not flank the target sequence, they will not be able to bind and amplify the desired DNA fragment.

Primer extension refers to the process of synthesizing a copy of a nucleic acid from a primer. A primer is a short piece of DNA or RNA that serves as a starting point for DNA synthesis. In primer extension, the primer is extended by adding nucleotides to its 3' end, using a DNA polymerase enzyme. This process allows for the amplification of a specific DNA sequence. The other options mentioned, such as amplicon, oligonucleotide, DNA templates, and thermal cycler, are related terms or tools used in DNA amplification techniques, but they do not specifically refer to the synthesis of a nucleic acid from a primer.

The length of the target sequence is determined by the 5' ends of the primers because the primers bind to the DNA template at specific regions, and the 5' ends of the primers mark the starting point for DNA synthesis. The primers dictate the length of the DNA fragment that will be amplified during PCR or other DNA amplification techniques.

Amplicon refers to the product of a polymerase chain reaction (PCR), which is a technique used to amplify a specific DNA sequence. During PCR, DNA templates are mixed with oligonucleotide primers and subjected to repeated cycles of heating and cooling in a thermal cycler. The primers bind to the DNA templates and serve as starting points for DNA synthesis by a DNA polymerase enzyme. As a result, multiple copies of the desired DNA sequence are generated, which is referred to as the amplicon.