I'm not going to do your homework for you. There are encrypted protocols, and there are unencrypted protocols. It shouldn't take much googling for you to determine which protocols are used by which applications, and whether or not it is secure.
If you actually need to provide a packet capture and anaylze the packets to show where the sessions start/end and what is encrypted and unencrypted, then I would start be reading the documentation provided on Wireshark's website. If you need more than that, there are classes you can attend to learn how to use Wireshark and how to do Packet Analysis.
You also could try the SANS Reading Room (http://www.sans.org/reading_room/
) for papers on Encryption, Protocols, etc...