Gmail/Crackberry Sync

Hi,
Sorry for another amateur question-but this one is starting to bother me. When i respond or delete a message from my Berry, my Gmail account recognizes those actions, and acts accordingly. On the flipside, if i respond or delete a message on my PC through Gmail, but Crackberry is not synced/doesn't register such action.

FOR INSTANCE, I'll delete an email on my PC/Gmail, and my Crackberry will "ding"/alert me a few seconds later that i still have a new email.

Help?!!?

Again, sorry for such amateur questions. Just went from three years of the iPhone to the Blackberry. Love this switch---just utterly confused! :confused: