A complementary strand is complementary to the template strand when in the opposite direction, in this case 5'-3', the nucleotides that it contains are complementary to those of the template strand. Thus, theĀ partially-made complementary strandĀ 5'-TAC-3' will bind to the template strand starting on theĀ 3'-ATG-5' portion. Then it is elongated by the DNA polymerase only up to the next nucleotideĀ A, not included, because its complementary nucleotide is T which is not available. So, the sequence of the new strand on DNA would beĀ 5'-TACGAACC-3'.
