What is Polymerase Chain Reaction? | PCR Explained

How does PCR work and what is it used for? Learn all about a polymerase chain reaction in this 2 Minute Classroom video.

Thanks for stopping by, this is 2 Minute Classroom and today we are talking about Polymerase Chain Reaction, or PCR as it’s more commonly known. First, let’s talk about what PCR is and how it works, and then I’ll give some examples of what PCR is used for.

PCR is a technique used to amplify or copy small specific segments of DNA.

For PCR to be successful, you need the DNA sample you want copied, DNA primers to identify the specific sequence of DNA you want to amplify, lots of raw nucleotides to form the DNA copies, and a heat resistant DNA polymerase to make the new copies. This all goes into a special stable solution.

Once all the ingredients are in, you run the solution through many temperature cycles until you reach the amount of DNA copies needed.

There are three main steps to this cycle.

Step 1 - Denaturation

The solution is heated allowing complementary DNA strands to separate so that all the DNA in solution is single stranded.

Step 2 - Annealing

The solution is cooled so that the DNA primers can bind to the specific region of DNA you are interested in.

Step 3 - Extension

The temperature is raised so that the DNA polymerase can bind and perform the necessary operation of synthesizing new DNA strands.

This cycle is repeated about 30 times, takes about 3 hours and creates over one billion copies.

So what is PCR actually used for?

PCR has many research based and practical applications.

It’s used for DNA mapping, like the Human Genome Project.

It’s used to check sections of DNA for genetic testing to determine potential disorders.

And my favorite application for PCR is in forensics. Whenever a crime is committed, the perpetrator almost always leaves their DNA at the crime scene. This could be hair, semen, skin, or blood. Investigators search for this evidence and thanks to PCR, can amplify the DNA and compare it to the DNA of suspects. This genetic information is then put into the FBIs DNA databade, CODIS

But it gets even better. Investigators have been able to take DNA evidence from crimes committed before CODIS was put together and run it through the current system. This has solved many cold cases and also exonerated prisoners who had been wrongfully accused, even some that were on death row.

Needless to say, PCR is one the most important scientific advances ever. And now you know why.

If you have additional questions I’ll do my best to answer those in the comments below.

Don’t forget to check out my other great videos and I’ll catch you next time.

[Spectre]

2 Minutes !! Wow . Took classes for almost half a semester and never understood the concept. It took you 2 minutes to explain it! Brilliant :)

[eyleenvasquez]

THANK YOU! My professor spent an hour explaining this and I did not understand at all. This really clarified it for me. SO HELPFUL

[heranmediasite]

wow 2 Minutes !! Wow . Took classes for almost half a semester and never understood the concept. It took you 2 minutes to explain it! Brilliant :)

[thatstheguy]

1:52 not for infectious diseases then. In fact I’ve heard the man who invented the test had warned not to use it for that purpose. Can’t confirm that. But I am pretty sure these tests can not test for specific strains, like covid. What a sham.
Couple that with the fact that there’s been directives passed on to hospitals to instruct their doctors to diagnose everything as cv. Dying from cancer, but also tested positive? Well that’s added to the tally of cv deaths. That’s how they’re inflating the numbers. If this were such a deadly disease, they would not need to be so liberal with the diagnosing.
This is not only happening in the US. It’s world wide. I’ve seen plenty of examples. They do not hide this fact.

[austinpalmer]

this man is a straight " G" bro thank you for this video. I wish I had found it 2 years ago to help explain this to people🙌

[chrispinezinamo]

i have understood it well because it is just straight to the main points. i need more of 2 minute classes.

[tasnimjerin]

Oh my god!! That was really helpful.
I took for 2 hours just to understand the concept of PCR and failed but your explanation was so simple and i got within seconds. Thank you so much.

[tamangsanu]

Within 2 minute basic required all information ! really brilliant sir!

[nashavi]

Best short explanation of PCR out there.

[missnosey]

*2019* squad? usefull thank u soooo much

[ThiNKBiologyThiNKVISION]

Awesome video... 👏👏
Amazed to see a broad topic discussed in 3mins by 2 minute Classroom.
ThankYou!

[StevePhillips]

Nice video made it seem simple and too the point. I dreamed last night I was talking with the PCR inventor. Karry Mullis. I'm trying to remember what he told me in the dream. It was a nice dream we shook hands first to introduce one another as I was standing and he was relaxed in the sofa. He give me a cheerful smile as we shook hands.

[ProgenexVideos]

Nice work on this video... PCR is our world...

[Rajveer-zj]

Damm !! You literally just Sault outed half of my burden!! Thnks dude

[ManiMasoumi-jynm]

amazing thank you so much for such clear and valuable explanation in just 2 min.. ✨✨✨✨✨✨✨

[dudfetbird]

1:59 Ahh Yes. The usual when the robber forgets his cemen in someone's house,

[reemana]

i have a question..
PCR is the same as DNA replication but in vitro, right

[sinemagadlela]

Thank you so much this was much easier to understand.... But I have a few questions: how do we specify which DNA to amplify?
What are potential obstacles to PCR standardization

[angustrains]

can you make a video on weather pcr testing ethically good please

[dprankypd]

Who's here because of the 2019 novel Coronavirus?