Much of this movement is to regulate the contents of the cell. This includes bringing material into the cell from the extracellular environment or the plasma membrane (endocytosis) or releasing material made within the the cell to the outside (exocytosis).
It really is an easy project...it just takes a little time. All and all, it took me about 6-8 total hours to make 4 bouquets, 10 bouts (my mom made those though) and about 15 centerpieces. I made two bouquets the day before our wedding and the other two the day of the wedding.
The ideal time to send out your invites is 8 weeks before the wedding date and at the latest 6 weeks before. This will give you enough time to collate all of the replies and inform the venue or caterer. When you send your invitations ask for them to be RSVP by 3 weeks to 2 weeks before.