[X4U] converting to Plain text and apostrophes

[cat soul]

I have a text version of my resume converted from RTF to Plain Text  
using OS X's Text Edit application.

I notice that in the plain text file, I have bunch of ’s  where  
there had been apostrophes.

Why does this happen, and is there a way to prevent it? If not, I  
guess I'm stuck doing search and replace...no big deal but it'd be  
nice to avoid the problem in the first place.

Thank you!

cs