Madrid, September 2016, option A, question 5.
Regarding the DNA replication of eukaryotic cells:
a) In the following double-stranded DNA molecule, the arrow indicates the opening direction of the double helix. Indicate from which chain (A) or (B) the conductive strand will be synthesized and from which the retarded strand. Explain why one strand is synthesized continuously and the other discontinuously (0.75 points).
5´- ATGACGTGA - 3´
3´- TACTGCACT - 5-
b) If the percentage of bases in one of the two strands of double-stranded DNA is: A = 30%, T = 28%, G = 22% and C = 20%, what will be the percentage of bases in the complementary strand? (0.5 points).
c) The DNA polymerase, Primasse and Helicase proteins participate in the initiation phase. Indicate the function that each one of them performs (0.75 points).