Basic Q: the role of DBA

I've read on a DB book that the Responsibilities of Database Administrator (DBA) are among others

1) Deciding the storage structure and access strategy
2) Liaising with users
3) Defining authorization checks and validation procedures
4) Defining a strategy for back-up and recovery
5) Monitoring performance and responding to changes in requirements

Using MsAccess, i can't put hand on these features, any explanation on what they are meant for and how they are implemented ?

thanks