What's the difference between what the senior consultant does compared to a fresh grad consultant, except for the salary?

Do senior consultants tend to handle external parties and clients independently on his own or is there a project manager fronting the user requirement discussion with the clients and directing the work? The senior consultant is to give the technical implementation inputs?

I believe for the fresh grad consultants, they would definitely be led by a PM at least due to their inexperience.

Also, are senior consultants expected to be promoted to project management role after certain number of years, or they can choose to stay at senior consultant level handling the implementation?