MCQ
Which of the following statements regarding cilia is not correct ?
  • A
    Cilia contain an outer ring of nine doublet microtubules surrounding two singlet microtubules.
  • The organized beating of cilia is controlled by fluxes of $Ca^{2+}$ across the membrane.
  • C
    Cilia are hair­like cellular appendages.
  • D
    Microtubules of cilia are composed of tubulin.

Answer

Correct option: B.
The organized beating of cilia is controlled by fluxes of $Ca^{2+}$ across the membrane.
b
(b) : Cilia are fine hair like vibratile, cytoplasmic processes borne by certain cell types. Their movement either propel the organism or move the medium past a fixed cell. The cilia are enclosed by a unit membrane which is an extension of the plasma membrane of the cell. Within the membrane, is a fluid matrix having a supporting axial shaft, or axoneme.The microtubules, single as well as double, are composed of the globular units of the protein tubulin. The arms of A microtubules contain a protein dynein. The latter is $ATPase$ enzyme which catalyzes hydrolysis of $ATP$ to $ADP$, and transfers the free energy released direct to ciliary work.

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