Hi, i'm wondering if this is correct for primers and sequencing etc. its just what i've gathered from trying to understand it..

 

So is it that DNA strands will respond to the primer of another if its

compatible, whereby the complementary base pairs are pieced together since

recognition is apparent in both strands.. kind of like piecing a jigsaw

together whereby even if there are missing pieces, in general the details

will be able to be placed in or connected because they are unique to their

localities of the puzzle..., therefore in DNA, the nucleotides are specific

to their strands and can therefore replace missing links for a complete

sequence, even if they are missing, because they still recognise the

specific genetic code...

Is this so that you can do PCR on your sample?

 

If so, then the primer that you have, are about 20 base pairs complimentary to the 3' and 5' end of the DNA strand. So once you have added your primers to the DNA sample, it will anneal to each end which provides a "handle" for DNA polymerase to bind and replicate the DNA strand.

 

Is that ok?

sorry i probably should of been more specific. im not doing any experiment or anything, i was simply asking if what i said about the sequencing is correct, just for knowledge sake...

 

while im on the matter, why are the ends of DNA called 3' & 5' and 2 or whatever ?

It's to do with the position of functional groups on the deoxyribose. The terminal hydroxy is at the 3' position, which means that it is on the 3' position on the ring. The starting phosphate is similarly on the 5' position on the ring. It's just the numbering convention.