iPhoto on your mac and iPhoto on your IOS devices are very different apps. They do not sync, but can share photos between the two apps.
For example, I have photos in events and albums on my computer, if I get the $4.99 app for my iPad and iPhone, will those events sync and be the same.
If you use iTunes photo sync to transfer photos from iPhoto on your mac to your iPhone or iPad, you can select which events, faces, albums, places you want to sync to your devices. Then you will see these photos in albums in iPhoto on your iPhone or iPad. You can edit and tag these photos on your IOS devices, but the changes will not sync back to your Mac or your other devices. If you want to see the changed versions on your Mac, you will have to share the edited photo to your camera roll individually and then connect the iPhone to your mac and download the changed photos from the camera roll to iPhoto on your mac.
Regards
Léonie