question: UW ID 2043 re: PCR

[PokerDoc]

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It says the DNA template is the region of DNA to be amplified yet, the correct answer is you need to have the nucleotide sequence of the regions flanking the target DNA, not the nucleotide sequence of the target DNA itself.

Its late maybe im not thinking straight, but can someone explain to me the difference between the DNA template which is required in PCR and the nucleotide sequence of the target DNA which apparently is not?

 

[mq123]

It says the DNA template is the region of DNA to be amplified yet, the correct answer is you need to have the nucleotide sequence of the regions flanking the target DNA, not the nucleotide sequence of the target DNA itself.

Its late maybe im not thinking straight, but can someone explain to me the difference between the DNA template which is required in PCR and the nucleotide sequence of the target DNA which apparently is not?

I'm not sure if this is right, but the new DNA is made starting from the edge of the DNA primers, going inward. So, you need primers that are flanking the target DNA, because they're used as starting points. If you had primers for the target DNA, then you would miss the edges....


Sorry, not the best way explain 🙂

 

[PokerDoc]

yeah im still confused.. I dont yet understand the distinction between the 'template' that is needed for PCR and the sequence of interest which is 'not needed' just the flanking sequence is needed.

 

[Tenacity]

yeah im still confused.. I dont yet understand the distinction between the 'template' that is needed for PCR and the sequence of interest which is 'not needed' just the flanking sequence is needed.

If you have the template complementary to the flanking sequences on both strands, then the sequence of interest will be amplified with it.

For example, if you have a sequence that starts with ATGCAGGTC ... and there are twenty bases before it, then the primer (template) will be complementary to that. The DNA polymerase will amplify that sequence and everything following the flanking sequence.

You COULD have the primer be complementary to the actual protein-encoding DNA, but that probably wasn't an answer choice, right?

 

[healingpower]

It says the DNA template is the region of DNA to be amplified yet, the correct answer is you need to have the nucleotide sequence of the regions flanking the target DNA, not the nucleotide sequence of the target DNA itself.

Its late maybe im not thinking straight, but can someone explain to me the difference between the DNA template which is required in PCR and the nucleotide sequence of the target DNA which apparently is not?

okay basically in this answer given ... DNA template = nucleotide sequence.
they are both the same... instead of repeating the term "DNA template" the second time in the last line( the second bold)... they used another word that meant along the same lines.

basically what the answer is telling u is that in PCR... the best way to get the actual bases we want to replicate is to find out what the flanking regions for the bases we want to replicate. We then use those create those 2 flanking regions (one for each side) and attach them to the DNA and replicate everything in between. So basically in PCR we dont really need to know the nucleotide sequence within the region we want to find out .. but just the flanking region.

 

[mofonyx]

PCR amplifies both strands anyway.

 

[PokerDoc]

okay basically in this answer given ... DNA template = nucleotide sequence.
they are both the same... instead of repeating the term "DNA template" the second time in the last line( the second bold)... they used another word that meant along the same lines.

basically what the answer is telling u is that in PCR... the best way to get the actual bases we want to replicate is to find out what the flanking regions for the bases we want to replicate. We then use those create those 2 flanking regions (one for each side) and attach them to the DNA and replicate everything in between. So basically in PCR we dont really need to know the nucleotide sequence within the region we want to find out .. but just the flanking region.

I follow you

but Nucleotide sequence was an answer choice, and in fact, the one I selected and it was wrong

 

[healingpower]

I follow you

but Nucleotide sequence was an answer choice, and in fact, the one I selected and it was wrong

i just looked up the question... and there are 2 answer choices that said nucleotide sequence... so now the second part of the answer choice determines the right answer. one of the choice was nucleotide sequence of the targeted dna.. and the other choice being the nucleotide sequence of the flanking parts of the target DNA... so then the latter becomes the answer choice.