Difference between protein concentrate vs isolate?

[StreetRacerX]

I'm still a newbie at the whole diet thing.... I plan on taking protein with my work outs, but whats the difference between whey concentrate and whey isolate? Also, where do you get ALA and is it the same as R-ALA?

I did read through alot of posts, but I still cant make a complete distinction between the two. Thanks for any info.