Biology - PCR Watch

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TwistedVidual
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Does anyone know why you use a primer in PCR? I know it anneals the DNA or something but I don't have a clue what that means.
Through my teachers incompetence I am still left in the dark after 2 weeks of trying to get the answer out of him, I don't even think he knows which is quite worrying....
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boygenious
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(Original post by TwistedVidual)
Does anyone know why you use a primer in PCR? I know it anneals the DNA or something but I don't have a clue what that means.
Through my teachers incompetence I am still left in the dark after 2 weeks of trying to get the answer out of him, I don't even think he knows which is quite worrying....
the target length of DNA to be copied is selected using primers. the primers are short lengths of nucleotides (artificially synthesised), which precisely complement the nucleotide sequence at the each end of the target DNA. in PCR, 2 primers are used to complement the target and opposite strands.
it does anneal to DNA, like you've said, which basically means it forms hydrogen bonds to its respective strand, when cooled and thus when reheated, through the action of DNA polymerase, DNA can be synthesised, extending from the primer position.
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TwistedVidual
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Why thankyou kind sir.
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Chocolate_Lover
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is this polymerase chain reaction or perliminance chain reaction
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Fluffy
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(Original post by Chocolate_Lover)
is this polymerase chain reaction or perliminance chain reaction

What is the perliminance chain reaction ???

perliminance isn't even in the dictionary!

PCR - in basic detail.

As for primers - described perfectly by boygenious.

You heat the DNA to denature it - part the two strands.

You then cool the DNA to the primers optimum temperature for annealing to the DNA (each primer will have it's own unique melting temp based on it's length and base composition) The primer then anneals to the DNA.

An enzyme called polymerase is then added along with dNTPs (free DNA bases). polymerase incorporates the free bases in the right order based on the denatured DNA template, basically extending the primer until you have a full copy of the sequence you are after.

Another period of denaturing to remove the first copies.

free primer then anneals to the templates (including the new templates formed from the last cycle).

This repeats for the number of cycles you've programmed the PCR cycler for.
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