Polymerase Chain Reaction Flashcards
A powerful method for amplifying particular segments of DNA.
PCR
PCR is carried out entirely biochemically in ____.
Vitro
PCR uses this enzyme to direct the synthesis of DNA from deoxynucleotide substrates on a single-stranded DNA template
DNA polymerase
DNA polymerase adds nucleotides to the _____ of a custom-designed oligonucleotide when it is annealed to a longer template DNA
3` end
The sample DNA that contains the target sequence.
DNA template
Type of enzyme that synthesizes new strands of DNA complementary to the target sequence
DNA polymerase
DNA polymerase that is most commonly used in PCR
Taq DNA polymerase
Enzyme that is used widely because of its higher fidelity when copying DNA
Pfu DNA polymerase
Two capabilities that makes DNA polymerase suitable for PCR
1) they can generate new strands of DNA using a DNA template and primers;
2) they are heat resistant.
Short pieces of single-stranded DNA that are complementary to the target sequence
Primers
“building blocks” for new DNA strands
Nucleotides (dNTPs or deoxynucleotide triphosphates)
What happens in Denaturation
DNA template is heated to 94°C. This breaks the weak hydrogen bonds that hold DNA strands together in a helix, allowing the strands to separate creating single stranded DNA.
What happens in Annealing
The mixture is cooled to anywhere from 50-70°C. This allows the primers to bind (anneal) to their complementary sequence in the template DNA.
What happens in Extension
The reaction is then heated to 72°C, the optimal temperature for DNA polymerase to act. DNA polymerase extends the primers, adding nucleotides onto the primer in a sequential manner, using the target DNA as a template.
GIve 5 applications of PCR
- Disease diagnosis and detection of pathogens
- Used in forensics laboratories
- Used to identify and to explore relationships among species in the field of evolutionary biology.
- In anthropology, it is used to understand the ancient human migration patterns.
- In archaeology, it has been used to spot the ancient human race.
Give 5 types of PCR
- Conventional PCR
- Real-time PCR
- Quantitative real time PCR (Q-RT PCR)
- Reverse Transcriptase PCR (RT-PCR)
- Multiplex PCR
- Nested PCR
Conventional PCR is applied in
- Selective DNA isolation
- Amplification and quantification of DNA
- Medical and diagnostic approaches
- Infectious disease diagnosis
- Forensic studies
PCR-based technique that couples amplification of a target DNA sequence with quantification of the concentration of that DNA species in the reaction
Quantitative PCR
A time-consuming process where the PCR products are analysed through gel electrophoresis.
Conventional PCR
qPCR facilitates the analysis of conventional PCR by ____________.
Providing real time detection of products during the exponential phase.
The principle of real-time PCR depends on the use of
Fluorescent dyes
Applications of Quantitative PCR
- Genotyping and quantification of pathogens
- MicroRNA analysis
- Cancer detection
- GMOs detection
- Microbial load testing
Real-time PCR is commonly used to measure ___________.
Gene expression
It is best suited for studies of small subsets of genes.
Real-time PCR
It can only be used for studying known genes.
Real-time PCR
First step in a real-time PCR reaction
The conversion of RNA to complementary DNA (cDNA)