Charlie writes, "I am a scientist at the University of Minnesota. In 1999, as an undergrad on a plant science internship, a friend and I were sitting on our dorm roof, wondering what the best nerdy science tattoo would be. The double helix down the leg or back was suggested, but we concluded that a chloroplast was a better fit for our scientific interests. As the photon-collecting organelle in plants, it's the source of energy for nearly all plant life and a fascinating biochemical machine. At that point in our careers, we found something that would represent our fascination with plants, no matter what field we chose to pursue. He is in botanical education (and didn't go through with the tattoo), I'm in horticulture." Click here to go to the full Science Tattoo Emporium.