No; bins are "virtual" folders. They can, but don't necessarily have to match whatever the folder structure is on your hard drive. For example, you can have 1 bin with files from three different folders on your hard drive, or three bins with files from a single folder on the hard drive. They're purely organizational from the Premiere interface.
That said, I frequently import folders into Premiere; this process creates a bin that matches the name of the folder from the OS interface. This is an easy way to keep yourself organized. You can also drag files from the Media Browser to the New Bin icon in the Project Panel; this will create a bin and put the files into it, with the bin name selected so you can immediately rename it.