110 likes | 222 Views
Sit with people you like to work with, in groups of 3, 4, or 5. Have clickers out. Download Wolfe-Simon et al. paper on arsenic life, and the arsenic life worksheet. Arsenic life. Which of the following is NOT one of the six major elements that make up life on earth? Hydrogen Sulfur
E N D
Sit with people you like to work with, in groups of 3, 4, or 5. Have clickers out. Download Wolfe-Simon et al. paper on arsenic life, and the arsenic life worksheet
Arsenic life • Which of the following is NOT one of the six major elements that make up life on earth? • Hydrogen • Sulfur • Phosphorus • Calcium • Nitrogen
Arsenic life • What cellular macromolecules contain large amounts of phosphorus? • Membrane lipids • Polysaccharides • Nucleic acids • Proteins • All of the above
Arsenic life • Cells have difficulty distinguishing between arsenic and phosphorus because: • Arsenic has a similar atomic radius to phosphorus • Arsenic has similar electronegativity as phosphorus • Arsenic lies immediately below phosphorus in the periodic table • All of the above • None of the above
Sit with people you like to work with, in groups of 3, 4, or 5. Have clickers out. Download Wolfe-Simon et al. paper on arsenic life, and the arsenic life worksheet
Fig. 1 Growth and electron microscopy of strain GFAJ-1. F Wolfe-Simon et al. Science 2011;332:1163-1166 Published by AAAS
Fig. 2 NanoSIMS analyses of GFAJ-1: extracted DNA and whole-cells elemental ratio maps. F Wolfe-Simon et al. Science 2011;332:1163-1166 Published by AAAS
Fig. 3 X-ray analysis of GFAJ-1 +As/–P described similarity of As coordinated like P in DNA. (A) EXAFS comparisons of the Fourier transformed data for As in model environments and GFAJ-1 (washed and fixed, collected on whole cells). F Wolfe-Simon et al. Science 2011;332:1163-1166 Published by AAAS
Arsenic life • Wolfe-Simon et al. showed that in GFAJ-1 cells, most of the radio-labeled arsenic was present in: • DNA & RNA • Proteins • Lipids • A phenol-soluble fraction • An aqueous fraction after organic extraction
Arsenic life • GFAJ-1 is: • An extraterrestrial life form • An obligate arsenophile (needs arsenic for growth) • A new species or strain of the Halomonas genus, known halophiles • A bacterium that is able to “breathe” arsenate