試題詳解

19. When a region of DNA must be repaired by removing and replacing some of the nucleotides, what ensures that the new nucleotides are in the correct sequence?
(A)DNA cannot be repaired and this explains why mutations occur.
(B)Specific enzymes bind the correct nucleotides.
(C)The new nucleotides basepair accurately with those on the complementary strand.
(D)The repair enzyme recognizes the removed nucleotide and brings in an identical one to replace it.
(E)The three-dimensional structure determines the order of nucleotides.