BA--- What does a Business Analyst does...

So.. what are the job functions.. roles.. responsibilites.. tools.. basically what the heck a BA does..
Lets try and figure out the broader aspects of a BA's routine life...

Role of a Business Analyst

• Structure of Development Team
• System Development Life Cycle (SDLC)
• Requirement Gathering
• Analysis and Design
• Implementation and Testing
• Deployment
• Requirement gathering.
• Different Types of Requirements.
• Requirement Gathering Techniques
• Role In SDLC
• Understanding of various Software construction Methods
  
• Typical Deliverables :
• Business Requirements
  
• Functional Requirement
• Non-Functional Requirements
• Report Specifications
• Tracebility Matrix

So this is what a BA does... but how does he do all these things and what the heck do they mean???