so we isolated the genomic dna. we measured that there was arsenic there. then we could tell that the arsenic wasn't just stuck, it was in a type of chemical environment or nearest neighbors looked like it was behaving like phospherous. it's like sitting at a dinner table with you and your neighbors and we might see how you're around. it looked like it was arsenic. we me surd it as arsenic. let's look at an artist rendition of what's going on in that cell. here we're seeing the beautiful elegant structure of the double helix of the dna. the phosphate.