In 3' and 5' what does the single quote mean?

[evointrigued]

If there is a 3' end of a DNA strand, what does the single quote mean?

Thanks.

[mith]

prime, it's a designation like #3.

[evointrigued]

Thanks. Is there a reason why it's denoted as a 3? Does "3 prime" mean 3 of something? Or is it merely a labeling system with no meaning behind it?

[BioLad]

3' is the number 3 carbon and 5' is the number 5 carbon as you count on the deoxyribose.

[BioLad]

Hmm It won't let me submit a link until I have 5 posts. Here is post #4

[BioLad]

And Number 5...then I will send a li nk with a pic of the numbering.

[BioLad]

OK, If you look Here (http://homepages.ius.edu/GKIRCHNE/DNA.htm) about half way down the page is an image with the numbers on the deoxyribose showing how it works.

[evointrigued]

Thanks. You both double-teamed to answer this perfectly.