Depends what your question is - does a full backup include all transactions in T-log? Yes. Does full backup checkpoint the T-log and truncate it? No. Does it shrink the T-log in a full backup? No.
To test this run this command:
this will show you the percentage of your T-log used. Run a full backup then run the command again and you will see that the percentage did not go down. If you are having T-log growth problems, you probably want to back it up periodically.
Another good command to know for the T-log is this one:
select * from ::fn_dblog(null,null)
This will show you the entries in your active T-log.
Ray Higdon MCSE, MCDBA, CCNA