Biology / Unit 6 Bio 1207 short lesson, about 20 seconds
Antiparallel Strand Orientation
Captions available
The idea
DNA's two strands run antiparallel, one oriented 5' to 3' and its partner oriented 3' to 5' across the same helix.
In practice
A phosphate on one strand's 5' carbon end faces its partner strand's 3' hydroxyl end at each end of the helix.
Where people slip
Antiparallel orientation is not the same fact as complementary base pairing — a helix needs both to hold its shape.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
Something wrong in this lesson? Flag it · Sources for Biology