WWWTP? Epigenetics Edition
Dan Hurley's piece in Discover's May 2013 issue really fascinated me. Covering the mouse research of Profs. Meany and Szyf, Hurley explained how tragic events in ancestral lifetimes are passed down to offspring via DNA methylation, altering gene expression for generations.
As my chemist's eyes flitted across the page, I smiled at some familiar friends on p. 51 - line structures of nucleotide base cytosine. Justone* a few small problem(s)...did you catch them???
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See that nitrogen at the bottom? In the language of my sophomore organic professor, it's "very unhappy" that way. Nitrogen usually gets three bonds and a lone pair of electrons; I won't over-critique the missing dots, but there needs to be one of three things on that structure:
As my chemist's eyes flitted across the page, I smiled at some familiar friends on p. 51 - line structures of nucleotide base cytosine. Just
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| Source: Discover 5.2013 |
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See that nitrogen at the bottom? In the language of my sophomore organic professor, it's "very unhappy" that way. Nitrogen usually gets three bonds and a lone pair of electrons; I won't over-critique the missing dots, but there needs to be one of three things on that structure:
1. A generic R-group (meaning a new carbon chain)
2. A proton (indicating the free cytosine base)
3. A "minus" sign (indicating an anion)
Kudos to the graphic artist, though, who actually used standard chemical notation here. Many general science mags would have just used a colored-in hexagon.
*Update, 6/17/13 - As commenters have piled on, we note the empty valences on the two aromatic carbons (carbanions?), as well as questions over whether a methyl group counts as a "compound."
*Update, 6/17/13 - As commenters have piled on, we note the empty valences on the two aromatic carbons (carbanions?), as well as questions over whether a methyl group counts as a "compound."
