Phosphorylation of ________ regulates which direction a flagellum rotates, thus controlling whether an organism runs or tumbles.
A) CheAW
B) CheB
C) CheY
D) CheZ

Question

Quizplus · Accepted Answer

CheY is phosphorylated by CheA, allowing it to bind to the flagellar motor and control its direction of rotation. When CheY is phosphorylated, it causes the flagellum to rotate counterclockwise, causing the organism to run in a straight line. When CheY is not phosphorylated, the flagellum rotates clockwise, causing the organism to randomly tumble and change direction. CheB and CheZ are involved in controlling the level of CheY phosphorylation. CheA is the protein kinase that phosphorylates CheY, but is not listed as an answer choice. CheAW is not a known protein involved in flagellar motor regulation.

Phosphorylation of ________ Regulates Which Direction a Flagellum Rotates, Thus