5' and 3' in DNA sequences

[cmp08]

How can you tell which end of a DNA sequence is the 5' end?

[carolinethorn]

Conventionally sequences are written down starting with the 5' end so if you are looking at the sequence from a database or journal article it is most likely written 5' to 3'. If it is written in reverse it would probably be annotated as such.
If you tell us a little more about the sequence we can help you be sure.
Best of luck,
Caroline

[Bob.Burkhart]

If you look at the site:
http://web.mit.edu/esgbio/www/dogma/repl.html

You'll find that the 3' is the OH end of a strand and the 5' is the Phosphorous end-- at least that's how I read it.

Good luck.