Yes for the most part, any port that has a dameon (service) running on it will be open. However. You can close the posrts with a personal firewall or stop running the service that opens the port ie a web server. Some applications may open a port but give a busy signal or no answear at all so to speak. Thats just a basic answear. Go here to get an idea of some ports that open with third party software.
http://www.practicallynetworked.com/..._port_list.htm