Final answer:
In axonemes, dynein sidearms are anchored on A tubules, crucial for the bending movement of cilia and flagella.
The correct option is B) A tubules
Step-by-step explanation:
In the axoneme, dynein sidearms are anchored on A tubules. Dynein, an ATP-powered motor protein, generates movement within cilia and flagella by walking along the B tubules of adjacent doublets. This action is essential for the bending of axonemes, which is a key component in cellular motility. Dynein-mediated movement is made possible due to the structural arrangement of microtubules within the axoneme, which typically shows a 9+2 arrangement in cross-section. This complex array consists of nine outer doublets that surround two central microtubules, with each doublet featuring A and B tubules. The sidearms of dynein, attaching to the A tubules, reach to the B tubules of the doublet next door, allowing for the sliding mechanism that enables bending.
The correct option is B) A tubules