Which of the following statements regarding cilia is not correct?
- The organized beating of cilia is controlled by fluxes of Ca2+ across the membrane
- Cilia are hair-like cellular appendages
- Microtubules of cilia are composed of tubulin
- Cilia contain an outer ring of nine doublet microtubules surrounding two single microtubules
The Correct Option is A
Solution and Explanation
The organized beating of cilia is primarily controlled by the sliding movement of microtubules and the action of motor proteins (dynein arms), not by fluxes of Ca2+ across the membrane. Calcium ions may be involved in other cellular processes, but they do not directly control the beating of cilia.
So, the correct option is (A): The organized beating of cilia is controlled by fluxes of Ca2+ across the membrane.
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Biodiversity and Conservation
The term ‘biodiversity’ is derived from the two words- ‘bios' which means life and ‘diversity’ i.e, differentiation or variation. Edward Wilson, the sociobiologist was the first to popularise the term ‘biodiversity’ in the year 1992. The term implies the occurrence of various plants and animals along with their variants such as biotypes, ecotypes and genes on earth. In our biosphere, the immense diversity or heterogeneity remains not only at the species level but also, at every level of biological organization that ranges from macromolecules in the cells to biomes.
Biodiversity and Conservation is a topic covered under the fifteenth chapter and Unit 5 of NCERT class 12 biology.