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Which of the following statements regarding cilia is not correct -
A
The organized beating of cilia is controlled by fluxes of $Ca^{2+}$ across the membrane
B
Cilia are hair-like cellular appendages
C
Microtubules of cilia are composed of tubulin
D
Cilia contain an outer ring of nine doublet microtubules surrounding two single microtubules
Detailed Solution
Cilia are small, hair-like outgrowths of the cell membrane that work like oars; this statement is correct.
The core of a cilium, the axoneme, has nine peripheral doublets of microtubules surrounding two central single microtubules, the 9 + 2 arrangement; this statement is correct.
The microtubules are made of the protein tubulin; this statement is correct.
The beating of a cilium is produced by the sliding of the peripheral doublets against one another, powered by the dynein arms, which have ATPase activity and use the energy of ATP.
The coordinated (metachronal) beating of the cilia is attributed to this ATP-driven mechanism and to the connections between the basal bodies.
According to the answer key of this paper, the statement that the organized beating is controlled by fluxes of $Ca^{2+}$ across the membrane is the one treated as not correct.
The core of a cilium, the axoneme, has nine peripheral doublets of microtubules surrounding two central single microtubules, the 9 + 2 arrangement; this statement is correct.
The microtubules are made of the protein tubulin; this statement is correct.
The beating of a cilium is produced by the sliding of the peripheral doublets against one another, powered by the dynein arms, which have ATPase activity and use the energy of ATP.
The coordinated (metachronal) beating of the cilia is attributed to this ATP-driven mechanism and to the connections between the basal bodies.
According to the answer key of this paper, the statement that the organized beating is controlled by fluxes of $Ca^{2+}$ across the membrane is the one treated as not correct.