The strands in the double helix
A) both run in the same 3' 5' direction, i.e., they are parallel.
B) have their 3' 5' directions opposed, i.e., they are anti-parallel.
C) can be either parallel or anti-parallel.
D) are perpendicular to one another.

Question

Quizplus · Accepted Answer

The strands in the double helix have their 3' 5' directions opposed, i.e., they are anti-parallel. One strand runs in the 5' 3' direction, while the other runs in the 3' 5' direction. This allows them to bond together through hydrogen bonds between complementary base pairs.

The Strands in the Double Helix