In the line 1. e4 d5 2. exd5 Qxd5 3. Nc3 Qe5+ 4. Be2 Qg5 5. Bf3 Qa5 6. b5... what happens if the queen takes the pawn? 

I'm sure it's something obvious, but I can't for the life of me figure it out.  Thanks in advance for any helpful responses!

It is a weak combination, the queen comes out too early, even if you don't win material, you should have a very large tempo advantaagee.  There are too many combinations to go into but white will have a hiuge advantage.

Thanks!