Question
These structures allow strains of Geobacter and Shewanella to grow thick biofilms on the anodes of microbial fuel cells. For 10 points each:
[10h] Name these structures composed of cytochromes like OmcA. They facilitate long-range electron transport from respiring bacteria into inorganic acceptors.
ANSWER: bacterial nanowires [or microbial nanowires; prompt on Type VI pili]
[10m] The Malvankar lab has shown that nanowire cytochromes conduct electrons because their adjacent heme groups align in a T-shape and interact through this intermolecular force. This attraction is the main reason that G:C (“G-C”) base pairs in DNA are more stable than A:T (“A-T”) ones.
ANSWER: pi–pi stacking [or pi stacking; prompt on pi interactions]
[10e] Although pi stacking makes DNA a decent nanowire on its own, its conductivity is greatly increased when it performs this process on nickel or silver atoms, coordinating the metals at multiple sites, like a claw.
ANSWER: chelation [or chelate effect or chelating]
Data
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