7.7 Summary
    1. 1 cells can use gas vesiclesto rise or fall in the water column
    2. 2 or magnetosomes toorient in a magnetic field
    3. 3 they sense their environment withmembrane-embedded chemoreceptors
    4. –+4 ...detecting changes in light,oxygen, and other chemicals
    5. 5 they may also assess their internalstate with cytoplasmic receptors
    6. flagellumarchaellumT4P6 receptors then send signals todirect the motility machinery

    Summary

    Concept Check Questions

    • What is the lattice arrangement of chemoreceptors in a sensory array?

    • Which proteins make up the baseplate of a chemosensory array?

    • What happens to the flagellar motor when a response regulator binds?

    • What cytoskeletal element organizes magnetosomes into a chain?

    Further Reading

    • Berg (1988). A physicist looks at bacterial chemotaxis [50].

    • Hazelbauer et al. (2008). Bacterial chemoreceptors: High-performance signaling in networked arrays [71].

    • Lower and Bazylinski (2013). The bacterial magnetosome: A unique prokaryotic organelle [72].

    • Schuergers et al. (2016). Cyanobacteria use micro-optics to sense light direction [73].