just need some help with this question: I can't seem to make sense of iii] and iv]. To be honest, i don't think i understand the entirety of PCR in this context and why primers are even used?? but parts i] and ii] are pretty easy to work out from basic principle (i think - i got i] = Xa and Xf, and ii] = Primer C)
I know part iv is something to do with introns and exons, i think. lol! sorry. anyway here is the question -
Six mRNA transcripts (XA, XB, XC, XD XE, XF) that encode protein X isoforms are expressed in skeletal muscle from a single gene whose exon structure was determined. The figure below shows an alignment of the six cDNA (mRNA) sequences with exon boundaries indicated (vertical broken) lines are guides to show the alignment of exon boundaries). The arrows above XA in the diagram indicate four pairs of PCR primers, the arrows labelled with the same letter are a primer pair.
8]i) Which cDNAs could be detected using primer pairs A and D? (10%)
8]ii) Which primer pair will detect all the mRNAs encoding protein X isoforms? (5%)
8]iii) A researcher wishes only to measure changes in transcript XB. Explain whether or not this is possible using only the primer pairs indicated in the diagram? (10%)
iv) Explain why primer pair C would not be able to distinguish between genomic DNA and cDNA? (15%)
I basically need a simplistic explanation of what this diagram is in relation to PCR and like why primers are used. i'm pretty much a novice