PCR 2.1.2 Copy your genes

5. How do you think PCR can be used to diagnose genetic diseases and disorders? PreviousNext

- A PCR test (combined with gel elect.) can confirm the presence of a suspected pathogen by using long primers specific to the pathogen of interest. You're just testing for the presence or absence of an amplicon.

2. Explain how a thermal cycler helps with the process of PCR.

- A thermal cycle uses a Peltier block to heat and chill the tubes very rapidly .- It does it over and over again through the PCR, that's why it's called thermal cycler (thermal = heats and chills, cycler = over and over).

Denature

- DNA samples are heated at 94-96 degrees Celsius for a couple minutes - The high heat then causes the DNA to separate into single strands

3. Explain how the process of PCR can be used in the identification of a disease pathogen. Provide evidence and examples from the outbreak investigation in Unit 1.

- PCR they'll amplify the DNA sequence of the pathogen , then after sequencing , they'll identify the identity of this DNA and identify the pathogen by comparing its genes with the gene bank .

Extension (PCR step 3)

- The temperature is raised to 72 degrees Celsius - The Taq polymerase attaches onto the primers - It then begins to read the DNA code and matches it with DNA nucleotides with the template to make more copies. The process above occurs in a thermal cycler, because it cycles the temp up and down

Annealing (PCR)

- The temperature lowers down into 50-65 degrees celsius for a couple minutes - The low temperature allows the DNA primers to attach onto the DNA template ( original DNA strand) at the beginning & at the end of the strand.

Explain how a scientist can target a specific gene or region of the DNA in a PCR reaction

- Use primers to identify a specific piece within the DNA

1. Explain how a scientist can target a specific gene or region of the DNA in a PCR reaction.

- use a positive control and negative control, to insure that the primers work correctly. - The PCR is done by mixing the primers, dNTPs, buffer, and Taq Polymerase in premix tube, aliquotting small amounts into test tubes, and then adding the test DNAs (positive control or negative control, or an unknown sample). -The test tubes are then placed into a PCR machine that will heat up and cool down according to a standard program, for a number of cycles. -After the PCR, the scientist can test if the reaction worked by running the reaction on an agarose gel.

How many steps are in a PCR test?

3; denature, anneal, Extension

Buffer

A place that provides a suitable chemical environment for a target DNA

polymerase chain reaction (PCR)

A technique for amplifying DNA in vitro by incubating with special primers, DNA polymerase molecules, and nucleotides.

Taq polymerase

A type of heat resistant that is derieved from hotsprings bacteria and helps DNA polymease with building.

Thermal Cycler

An instrument that automatically cycles through different temperatures used to complete PCR reactions

DNA Nucleotides

DNA Nucleotides: The building blocks that are used by the polymerase. - Cytosine (C), thymine (T), adenine (A), guanine (G)

Target DNA

The fragment of DNA which PCR uses to produce multiple copies

Equipment used in PCR

Thermal Cycler, Taq Polymerase, Target DNA, Buffer, DNA Nucleotides, Primers,

Second step of PCR

annealing

First step of PCR

denaturation

Third step of PCR

extension

Primers

short segments of DNA that guide DNA polymerase to the section of DNA to copy