Using Ubuntu to host WordPress, I am wondering about permissions of files for newly installed plugin, how would they be executable?

permissions for the folder that has the wordpress installation:

drwxrwsr--  7 ubuntu deploy  4096 Oct 17 17:56 blog

Should I configure blog directory so that new files inherit blog directory permissions too? or this is already taken care of by WordPress? ex: it will run command chmod 775 at the newly installed plugin folder??

Any enlightenment is appreciated? I really like to understand.