Some restriction enzymes do not leave sticky ends when cutting DNA molecules; rather, they cut a restriction site down the middle and leave "blunt-ended" DNA molecules, which do not have any single-stranded nucleotide extensions. Which of the following is not a likely outcome when trying to insert a gene into a plasmid when both have been cut with the same "blunt-ended" restriction enzyme?
A) The gene might be inserted into the plasmid by forming hydrogen bonds.
B) The gene might be inserted into the plasmid multiple times in a row.
C) The gene might insert into the plasmid in the proper (forward) orientation.
D) The gene might insert into the plasmid in the wrong (backward) orientation.

Question

Quizplus · Accepted Answer

Blunt-ended ligation relies on the formation of phosphodiester bonds between adjacent nucleotides, not hydrogen bonds, which are responsible for base pairing between strands, not for joining the ends of DNA fragments.

Some Restriction Enzymes Do Not Leave Sticky Ends When Cutting