試題詳解

11. Why does a DNA strand grow only in the 5' to 3' direction?
(A) because DNA polymerases can only add nucleotides to the 3' end of the growing molecule
(B) because DNA polymerases can only add nucleotides to the 5' end of the growing molecule
(C) because the DNA molecule only unwinds in the 5' to 3' direction
(D) because DNA polymerase requires the addition of a starter nucleotide at the 5' end
(E) because the 5'-end is capped