Question

why is the forward primer in PCR when adding a sticky end not complementary to the DNA but the reverse primer is?

Answer 1

•The forward primer attaches to the start codon of the template DNA (the anti-sense strand), while the reverse primer attaches to the stop codon of the complementary strand of DNA (the sense strand). The 5' ends of both primers bind to the 3' end of each DNA strand.

•Eg :- Forward primer for sequencing promoter: 5’ccaaaatgtcgtaacaactc-3’ – on antisense strand ,

• that means the sense strand having the palindromic sequence of above.

•On which the reverse primer will attach. That means the forward primer here is having a complementary sequence of reverse primer , that why it is attached to reverse primer.   And sticky end not having it.