OK, you've got a few balls in the air with that.
The (virtual) "disk" itself, then the partition are as you might expect. The pv is a LVM emulation for allowing dynamic resizing of the storage pool (more useful with multiple disks/partitions). It looks like gparted handled resizing that for you.
Within the pv is the lv(s) which contain the filesystem (simplified view). This is what needs to be resized (as well). If you want all that free space in the ubuntu-lv, try this - it will resize the lv and the filesystem at the same time. LVM is extensively documented (and the following is untested) so I suggest you read up on the commands available.
Code:
sudo lvextend -r -l +%FREE /dev/ubuntu-vg/ubuntu-lv