Question about Component Cables for HDTV

I am curious about component cables for HDTV & DVD players. I realize that the signal is unique and requires 3 cables to carry it. However, are the cables themselves unique. In otherwords, are the red, green & blue cables each unique? Could you use 3 regular COMPOSITE (yellow) cables to carry the signal? If so, would you still get the same quality? It seems to me, the cables for component video and composite video are the same, its just the signal that they carry that is different. If that's the case, all those expensive "component" cables that are sold are a big shame. Someone help me!