Quiz | Real-Time PCR

Explanation
Kary Mullis received the Nobel Prize in Chemistry in 1993 for inventing PCR, which stands for Polymerase Chain Reaction. PCR is a technique used to amplify a specific segment of DNA, allowing scientists to study and analyze it in greater detail. Mullis' invention revolutionized the field of molecular biology and has since become an essential tool in various scientific disciplines, including genetics, forensics, and medical diagnostics.

Explanation
During the extension/elongation phase of DNA replication, nucleotide triphosphates (dNTPs) are added to the growing DNA strand. This is when the DNA polymerase enzyme catalyzes the formation of phosphodiester bonds between the incoming nucleotides and the existing DNA strand, resulting in the elongation of the DNA molecule. This process ensures the accurate replication of the genetic information contained within the DNA molecule.

Explanation
PCR stands for Polymerase Chain Reaction. This technique is used to amplify a specific segment of DNA through a series of heating and cooling cycles. It involves the use of a DNA polymerase enzyme to copy and replicate the DNA region of interest. The process starts with denaturation, where the DNA strands are separated. Then, primers bind to the target DNA sequence, allowing the DNA polymerase to synthesize new DNA strands. This cycle is repeated multiple times, resulting in the exponential amplification of the desired DNA fragment. PCR is widely used in various applications, including genetic research, diagnostics, and forensic analysis.

Explanation
The correct answer is False. The sequence order of RT-PCR is as follows: 1. Denature, 2. Anneal, 3. Extend, and 4. Detect. This is the standard procedure for reverse transcription polymerase chain reaction, where the RNA template is first denatured to separate the strands, then the primers anneal to the target sequence, followed by extension of the primers by a DNA polymerase, and finally the detection of the amplified DNA product.

Explanation
Real-time PCR assays incorporate dyes that bind double-stranded DNA, which allows for the detection and quantification of the DNA target. They also incorporate an internal hydrolysis probe, which is a specific sequence of DNA that binds to the target DNA and releases a fluorescent signal during amplification. This probe helps in the accurate detection of the target DNA. Finally, the results of real-time PCR assays can be interpreted as either a plus/minus result (presence or absence of the target DNA) or as a quantitative result (measuring the amount of target DNA present).

Explanation
A PCR reaction that contains only one copy of the target sequence may amplify, but its detection is not likely to be highly repeatable. This is because when there is only one copy of the target sequence, there is a higher chance of experimental variability and errors in the detection process. Therefore, although amplification may occur, the results may not be consistently reproducible.

Explanation
Reverse transcriptase is an enzyme that is responsible for the synthesis of complementary DNA (cDNA) from an RNA template. It is commonly used in molecular biology techniques such as reverse transcription polymerase chain reaction (RT-PCR) to convert RNA into DNA. This enzyme is derived from retroviruses and is capable of catalyzing the reverse transcription of RNA into DNA. Therefore, it is the correct answer for the given question.

Explanation
In the reverse transcriptase reaction, primers are used to initiate the synthesis of cDNA from RNA. These primers can be target sequence specific, meaning they are designed to bind to a specific region of the RNA molecule. They can also be random hexamers, which are short DNA sequences that bind randomly to the RNA template. Additionally, oligo dT primers, which are composed of a string of thymine bases, can be used to bind to the poly-A tail found on most mRNA molecules. Therefore, all of the given options - target sequence specific primers, random hexamers, and oligo dT primers - can be used to prime the reverse transcriptase reaction.

Explanation
RT-PCR (Reverse Transcription Polymerase Chain Reaction) is a technique used to amplify and detect specific RNA molecules. It is commonly used in various applications such as drug therapy efficacy, verification of microarray results, allelic discrimination assays or SNP genotyping, and quantitative mRNA expression studies. In drug therapy efficacy, RT-PCR can be used to determine the effectiveness of a drug by measuring the expression levels of specific genes. In verification of microarray results, RT-PCR can be used to validate the gene expression data obtained from microarray experiments. In allelic discrimination assays or SNP genotyping, RT-PCR can be used to detect specific genetic variations. In quantitative mRNA expression studies, RT-PCR can be used to measure the expression levels of specific mRNA molecules.

Explanation
Human errors can limit the accuracy of real-time PCR results in several ways. Incorrect data analysis can lead to misinterpretation of the results and incorrect conclusions. Improper assay development, such as using incorrect primer sequences or suboptimal reaction conditions, can result in inaccurate measurements. Additionally, unwarranted conclusions can be drawn if proper controls and validation steps are not followed, leading to false interpretations of the data. These human errors highlight the importance of careful and meticulous experimental design, execution, and analysis in real-time PCR to ensure accurate and reliable results.