Well it would take forever to try and write about every part of a computer, so what I would do is take a look at something like this:
Howstuffworks "Computer Hardware Channel"
just to understand the basics. Once you have that, just google the specific parts that you don't understand. If that doesn't work, ask a specific question here. In order to build your own pc, you don't need to fully understand everything that goes on in the pc though, what you need to know is :
1. What do I want to do with My PC? Game, photoshop, e-mail & web surfing etc...
2. What Parts do I need? probably: Case, PSU, Motherboard, CPU (and heatsink), Ram, Video Card, Hard Drive, DVD Drive... and anything else you want to add.
3. What is my budget?
4. Do I want to Overclock my CPU or Videocard?
Once you know those things then make a post in the new builds section and ask for advice. Advice on which parts and why they are better then other parts. This will help you understand small details. Do you need to know what your chipset does.. maybe... you need to know enough not to buy a amd processor with a intel p45 chipset. But you don't need to know exactly how it does what it does. Here look at this:
Intel P45 Express Chipset - Overview
It will give you some details on that specific chipset, and based on the features and benefits you will get an idea of what all chipsets do.
So yes to answer your question your choice of components are limited based on your choice of your chipset. When you look at a motherboad it will tell you the compatible products with it.