What is the direction of the rainbow?

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Sandra Porter

and what is the volume of the sea?

This sounds a bit like the beginning of a poem but it's really the answer to the question we posed last week on a Digital Biology Friday.

i-3faa77de2c8e6cc50b5fa2cbca9c38b0-rainbow_direction.pngWe can see, in the sequence window, that two strands are both labeled 5' on the left side and 3' on the right. We call this direction "five prime to three prime."

But, when we look in the structure window, we see that the two strands are oriented in the opposite direction relative to each other. The 5' end of one strand is located across from the 3' end of the other strand.

(Note: I added the arrow and labels, this wasn't done by Cn3D).

Naturally, we have a fancy name to describe this orientation. We say that the DNA strands are "antiparallel."

Since I'm feeling a bit antiparallel at the moment, myself, I'll leave to you to explore on your own until next week.