Question
This mode of movement occurs when bundles of flagella moving counterclockwise become unbundled as some of the flagella switch rotational direction. For 10 points each:
[10m] Name this mode of movement exhibited by peritrichous (“pair-ih-TRICK-us”) bacteria like Listeria monocytogenes and E. coli. During chemotaxis, bacteria suppress this kind of motility in favor of directed runs along concentration gradients.
ANSWER: tumbling [or tumbling motility; or word forms of tumble; accept run-and-tumble motion; accept twiddling motion or word forms of twiddle]
[10h] The concentration of this protein’s phosphorylated form controls the direction of flagellar motion. The histidine kinase CheA (“kee-A”) phosphorylates this protein, which binds FliM to stabilize counterclockwise motion and induce tumbling.
ANSWER: CheY (“kee-Y”) [accept CheY-P]
[10e] Run-and-tumble motion can be modeled as a three-dimensional one of these phenomena biased by the direction of flagellar motion. Diffusion without a chemical gradient is also modeled as this kind of process.
ANSWER: random walk [prompt on random processes or stochastic processes; prompt on walks; prompt on Brownian motion or Wiener processes]
Data
Team | Opponent | Part 1 | Part 2 | Part 3 | Total |
---|---|---|---|---|---|
Chicago C | Illinois A | 0 | 0 | 10 | 10 |
Columbia B | WUSTL A | 0 | 0 | 10 | 10 |
Cornell B | Brown A | 0 | 0 | 10 | 10 |
Florida A | Yale B | 0 | 0 | 10 | 10 |
Florida B | Duke A | 0 | 0 | 10 | 10 |
Georgia Tech A | Penn State A | 10 | 0 | 10 | 20 |
Georgia Tech B | Claremont A | 0 | 0 | 0 | 0 |
Harvard A | Minnesota A | 0 | 0 | 10 | 10 |
Houston A | Penn A | 0 | 0 | 0 | 0 |
MIT A | Michigan A | 10 | 0 | 10 | 20 |
Maryland A | Rutgers A | 0 | 0 | 10 | 10 |
NYU A | Minnesota B | 0 | 0 | 0 | 0 |
North Carolina A | Chicago B | 10 | 0 | 10 | 20 |
Ohio State A | Columbia A | 10 | 0 | 10 | 20 |
Purdue A | South Carolina A | 0 | 0 | 10 | 10 |
Stanford A | Northwestern A | 0 | 0 | 10 | 10 |
Texas A | Rutgers B | 0 | 0 | 10 | 10 |
UC Berkeley A | Johns Hopkins A | 10 | 10 | 10 | 30 |
Virginia A | Imperial A | 0 | 0 | 10 | 10 |
WUSTL B | UC Berkeley B | 0 | 0 | 10 | 10 |
Yale A | McGill A | 10 | 0 | 10 | 20 |