Question

In the axoneme, nexin

A) transports tubulin to the axoneme tip for assembly.
B) generates force for outer doublets sliding past each other.
C) projects inward from each doublet toward the central pair microtubules.
D) links adjacent outer doublets to limit sliding.
E) connects each outer doublet to the plasma membrane

Answer 1

In the axoneme of cilia and flagella, nexin links adjacent outer doublets to limit their sliding, maintaining structural integrity as dynein proteins generate bending movements.

Step-by-step explanation:

In the structure of the axoneme, which is the core of cilia and flagella, nexin is a protein that has an essential role. Nexin does not transport tubulin or generate force directly; instead it functions in a regulatory capacity. The correct answer to the function of nexin in the axoneme is that it links adjacent outer doublets to limit sliding (D). By linking outer doublets, nexin helps maintain the structural integrity of the axoneme as dynein motor proteins generate force to cause the axoneme, and thus cilia or flagella, to bend.