Of course you can.
Open Disk Utility and format the drive as a Mac OS X Extended (Journaled). After that you can partition the drive. Each partition can then be formatted, erased and repaired individually.
HOWEVER - please note that it is not advisable to run Time Machine and other important files from the same physical drive! If the drive fails, you lose all the data on it. Hard disks are cheap and I suggest you always have a backup of inportant data on another drive. Hard drives WILL fail, it is just a question of time!