This question had a list of choices. The choices were:
A) 5'-phosphate / 3'-hydroxyl
B) 3'-phosphate / 5'-hydroxyl
C) 5'-deoxyribose / 3'-base
D) 3'-base / 5'-deoxyribose
Dna replication always proceeds in only one direction because the 5'- PHOSPATE of the incoming nucleotide is attached to the free 3'-HYDROXYL of the growing dna strand.
Choice. A.
