a question about true crypt and encrypt partition

Hi
i have a question about truecrypt behavior

well i use acronis disk director to create a parition
acronis dd will update the fist sectors of the hardisk , i guess add some info in the sectors before the partition, right?

well i encrypt the partition

what does tc exactly encrpy ?
the data (empty because i create the partition without coping files)
or the data in the boot mbr and the data before the partition


is enough to delete with acronis this partition to get rid of the truecypt data?
or should i use truecrypt to decrypt this partition and reestablish the original condition

thanks
best regards