Question

The mandatory combination of ions responsible for the association of microtubules are?
A. $N{a^+}$ and $C{a^+}$
B. $M{g^{2+}}$ and $C{a^{2+}}$
C. $C{l^-}$ and $C{a^{2+}}$
D. $N{a^+}$ and ${K^+}$

Answer 1

Polymers of tubulin which forms a part of the cytoskeleton are known as microtubules. These extensions facilitate in providing shape and structure to the cells. The internal structure of cilia and flagella is also made up of these elements. Also involved in cell division and a variety of cellular processes.

Complete answer: The major ions involved in the microtubule assembly are calcium and magnesium. The magnesium ion favors the assembling of these structures, while calcium ions inhibit the assembling. Calcium helps in the regulation of the assembly intracellularly. Thus, the two ions help in balancing the activity of the microtubule assembly.
Considering the other options:
-Sodium ions don’t have an effect on the assembly of microtubules. And has no role in maintaining the homeostasis of this process.
-Chlorine ions also do not play any role in the microtubule association.
-Potassium also plays no role in the process.
Thus, the most appropriate combination was given in option B, that is, the mandatorily required combination of ions for microtubule association are calcium and magnesium.

Note: Cilia and flagella are the two cellular structures that are formed from microtubules. Cilia are hair-like extensions protruding from the cells and facilitate movement in many unicellular organisms, cilia are also present within many tubular organs in the human body aiding in the movement of particles through it such as the cilia in fallopian tubes which helps in the movement of the ovum through it. Flagella are longer variants of cilia and have a whip-like appearance. The main function of these appendages is to facilitate the movement of the cells.