Consistent backup of large DB --single-transaction

I need to mysqldump a large DB (330 GB) in order to set up a slave for replication.

• Does --single-transaction allow me to dump the entire DB without shutting mysql down and keeping it down for the duration?
• If I put a read lock on, can I get my bin information but then can release the lock and dump using --single-transaction so there is minimal downtime to users?