Today i heard the phrase, her/his "periderm is worse than " his/her "bite". (I can't remember the gender.) Puns make the world go round. With that in mind, I scoured the internet for biology puns...

http://www.xs4all.nl/~jcdverha/scijokes/4_3.html#subindex

I think some of them are just downright nerdy, don't you?

Of course, the best puns are the ones you come up with yourself...so let me take a crack at this:

"What did the DNA say to the RNA? We don't need U here."

Ok, I can't think of any others. :(

Perhaps I'm not cut out to be a comedian.

Oh well, pass me a gamma-radiation sterilized scalpel and I'll make a wet-slide of that apple I wanted to eat.