Question

Microtubules are present in
A. Bacteria
B. Viruses
C. Animal cells
D. Mycoplasma

Answer 1

The cytoskeleton is made up primarily of microtubules. They are present in all eukaryotic cells and play a role in mitosis, cell motility, intracellular transport, and cell shape preservation. Alpha- and beta-tubulin subunits are organised into linear protofilaments to become microtubules. A single microtubule is made up of $10$ to $15$ protofilaments ($13$ in mammalian cells) that wind together to create a hollow cylinder with a diameter of $24{\text{ }}nm$.

Complete solution:
Let us solve this question by analyzing the type of cells in each of the options.
Option:A – Bacteria are prokaryotic organisms and lack microtubules in their cells. Although bacterial cells contain tubules and fibres, they are not homologous to microtubules.
So, Option:A is not correct.
Option:B – Viruses are acellular organisms that only thrive as parasites in a living cell and hence they lack microtubules in their cells.
So, Option:B is not correct.
Option:C – Animal cells contain microtubules and these microtubules are used in the formation of various structures like centrioles, flagella etc.
So, Option:C is the correct answer.
Option:D – Mycoplasmas also called PPLOs are also prokaryotic organisms and lack microtubules in their structures.
So, Option:D is also not correct.

Note:
Microtubules are tubular structures with a diameter of $24\,nm$ that are made up of a family of conserved proteins termed tubulin in eukaryotic cells. They have a role in ciliary motility, nerve cell elongation, pigment migration, centrosome formation, and chromosome movement, among other things. Microtubules are longer filaments that are continuously constructing and dismantling; and bundles of microtubules create the cilia and flagella observed in protozoans and multicellular animal cells.