Question

RNA is transcribed and then modified. What modifications affect non protein-coding genes and how do they do it (2 examples)

Answer 1

I'm not sure if I've quite understood the question but modifications of transfer RNA include methylation of bases and the presence of pseudouridine in the sequence. You can get more details here:
http://en.wikipedia.org/wiki/Transfer_RNA

I hope this is what you were looking for, if not post again and I'll see if I can help.

Answer 2

I thought that are things like splicing of RNA, or somethin like that. You could read more about it on the Lehninger.
Chapter 28 if I'm not wrong has a amazing explanation about RNA splicing and anothers mRNA modifications

http:/ /www.4shared. com/office/MKdGdCpT/Principles_of_Biochemistry_5th.htm