Comments on: We Love PCR

By: Deanna

Deanna — Wed, 03 Mar 2010 03:09:01 +0000

PCR stands for Polymerase Chain Reaction. PCR enables millions of copies of a specific strand of DNA, or deoxyribonucleic acid, to be produced in approximately two hours. This whole process of copying requires the use of bacteria for amplifying DNA. The first step of this process starts with a denaturing step. Different samples of specific DNA are heated to 94- 96 degrees C for one to several minutes to denature, separate into single strands. After you’ve done that the temperature is lowered to 50- 65 C. By doing this step it allows the left and right primers to anneal, base pair, to their complementary sequences, causing the DNA sequence to be amplified. Following that step, the temperature is then again raised to 72 degrees C for one to several minutes. This allows each polymerase to attach to each priming site and synthesize a new DNA strand. And last, but not least the cycle is repeated to make another strand of specific DNA. The site I found this information on was :
http://www.dnalc.org/resources/animations/pcr.html.

By: Alec Freudenstein

Alec Freudenstein — Tue, 02 Mar 2010 16:39:21 +0000

“PCR is a relatively simple and inexpensive tool that you can use to focus in on a segment of DNA and copy it billions of times over. PCR is used every day to diagnose diseases, identify bacteria and viruses, match criminals to crime scenes, and in many other ways.” This information was found on: http://learn.genetics.utah.edu/content/labs/pcr/

Also, “PCR amplification of a gene to make millions of copies, allows for detection and identification of gene sequences using visual techniques based on size and charge (+ or -) of the piece of DNA.” this information was found on: http://biotech.about.com/od/pcr/a/PCRtheory.htm

By: Marielle

Marielle — Mon, 01 Mar 2010 15:21:48 +0000

PCR is a polymerase chain reaction. It copies a piece of DNA and creates a chain of many pieces. PCR needs a DNA template to copy and oligonucleotides (also called primers) which are pairs of shirt DNA sequences.
1. Double-stranded DNA denaturation
2. Primer annealing to template DNA
3. Primer extension
Denaturation means that the weak hydrogen bonds are disrupted and make two single stranded DNA strands. Primer annealing is when primers collide at the annealing temperature and bind with their complementary sequences.

http://www.uq.edu.au/vdu/PDU_PCR.htm

By: Jesse

Jesse — Sun, 21 Feb 2010 20:42:16 +0000

Scientists love PCR because it basically amplifies DNA and also ever since they came out they have cloned cells and it makes everything easier for scientists. PCR stands for polymerase chain reaction and it works based on the ability of a DNA polymerase enzyme that can synthesize a complimentary strand to a targeted segment of DNA in a test tube mixture consisting of only 4 DNA bases.

http://www.contexo.info/DNA_Basics/polymerase_chain_reaction.htm

By: Matt C.

Matt C. — Fri, 19 Feb 2010 22:11:15 +0000

PCR stands for polymerase chain reaction according to http://www.uq.edu.au/vdu/PDU_PCR.htm. This website also said PCR is a “…technique for copying a piece of DNA a billion-fold.”

By: amy breslin

amy breslin — Mon, 15 Feb 2010 02:42:06 +0000

Yes… these videos are amazing! I posted these on my blog last semester

By: Jim Hutchins

Jim Hutchins — Mon, 18 Jan 2010 01:16:11 +0000

In Ye Olden Days of Yore, before PCR, it was almost impossible to amplify DNA. (And, as the British say, amplifying RNA was Right Out.)

Let’s say you had a little bit of DNA, maybe just a few dozen molecules from a crime scene. (Remember that a few dozen molecules is maybe 10^-20 moles of DNA, a very very very small number.) Before PCR and before thermostable DNA polymerase, you had to have three water baths set up, at three different temperatures, and you had to physically move the tube with your sample from one water bath to another. Each “round” as you came around to the lowest temperature bath (what we call the annealing temperature), you would have to get out your micropipet and put in more DNA polymerase. It was tedious, it cost a fortune, and no one had invented trip-hop music yet so you couldn’t even stay awake.

After PCR and thermostable DNA polymerase (e.g. Taq), all we had to do was just set up the reactions, put them in the thermal cycler, and go home to our pets and families. Everyone was happier.