One of the AP Biology standards refers to quorum sensing in bacteria as an example of communication among organisms, which is why I found this video (How Bacteria "Talk," by Bonnie Bassler) and created the write-a-long for my AP Bio classes.
The video is a bit long (about 18 minutes), but it is very interesting. The worksheet requires students to pay attention to answer five multiple choice questions and three "write out the answer" questions. All questions/answers come from the video.
Note that this WAL does not have a summary/applications section like most of my other video WALs do- it's just a straightforward fill-in-the-blank sheet all the way through.
This product DOES come with the answer key at the end.