Pcr why 94 degrees

It is used in the early stages of processing DNA for sequencing , for detecting the presence or absence of a gene to help identify pathogens during infection, and when generating forensic DNA profiles from tiny samples of DNA. How does PCR work? We will explain exactly what each of these do as we go along. PCR involves a process of heating and cooling called thermal cycling which is carried out by machine.

There are three main stages: Denaturing — when the double-stranded template DNA is heated to separate it into two single strands. Extending — when the temperature is raised and the new strand of DNA is made by the Taq polymerase enzyme.

These three stages are repeated times, doubling the number of DNA copies each time. A complete PCR reaction can be performed in a few hours, or even less than an hour with certain high-speed machines.

After PCR has been completed, a method called electrophoresis can be used to check the quantity and size of the DNA fragments produced. Related Content:. What is DNA replication? What is DNA? What is a gene? What is DNA sequencing? How helpful was this page? What's the main reason for your rating? Which of these best describes your occupation? What is the first part of your school's postcode? This is because extension occurs when the sample is inside of the annealing heat zone.

Annealing takes place as the sample travels between heat zones. Device speed 23 minfor 30 cycles without time optimization is competitive with other rapid PCR designs for efficiencies comparable to a commercial machine. Abstract The performance of a novel thermal cycler has been characterized in a cycle PCR. Gov't, Non-P. Research Support, U. Gov't, P.