So there's a part where they explain that the double helix of the DNA strand gets forked into two separate strands.
One strand gets smoothly "copied" just as soon as it's spooling out of the fork location. Continuously in one direction.
The other strand (because of it's directionality) needs to be taken section by section at a time and is copied backwards.
Compare all of that with ויסע ויבא ויט (Shemot 14) and it's pretty striking.