I wrote a blog post a few years ago explaining how molecules get to the right place at the right time. The short answer is that cells are nothing like the nice, peaceful animations. Cells are extremely crowded and things move extremely fast. Glucose molecules, for instance, move around cells at 250 miles per hour and collides with something billions of times a second. An enzyme might collide with a reactant 500,000 times a second. And proteins can spin a million times per second. So as you suspect, by random chance molecules are in the right spot very frequently.
#biology #the more you know