Write Complementary Sequence for DNA strand

Question

I have the answer to this problem; however, I cannot seem to figure out why or how to solve it:

What is the 5'-3' sequence of the complimentary DNA strand for the following image? The primer represents what is in parenthesis.

5' A G C C T A G (G C A A C) T C G T T T A 3'

The answer is G U U G C C T A G G C T

If someone could explain to me how to arrive at that answer, I would greatly appreciate it! Thanks.

Answer 1

The complimentary strand will begin when enzymes first encounter the primer as it proceeds from the 3' end. Therefore, the 3' end of the primer, beginning with CAAC will be the first part of the strand and ending with A on the 5' end.

Remember that on the DNA strand, C(Cytosine) pairs with G(Guanine) and A(Adenine) pairs with T(Thymine).(U(Uracil) is a substitute for T only in the mRNA.) Using this, pair the nucleotides of the DNA strand with the appropriate nucleotide from the mRNA strand.

However, I don't know the context of the question, but usually the DNA strands always contain Thymine and the mRNA strands contain Uracil.