Final answer:
The rare type of tubulin located in the pericentriolar material responsible for nucleating microtubule formation is gamma-tubulin. It is crucial for initiating the polymerization of microtubules, which are integral to various cellular structures and functions. The correct answer is option 3.
Step-by-step explanation:
The rare type of tubulin that is located in the pericentriolar material, responsible for nucleating microtubule (MT) formation, is gamma-tubulin. This question pertains to the composition and function of microtubules within the cytoskeleton of eukaryotic cells. Microtubules are dynamic structures consisting of α-tubulin and β-tubulin dimers that form hollow tubes essential for many cellular processes, including maintaining cell shape, intracellular transport, and cell division.
The centrosome, which is the microtubule-organizing center found near the nucleus of animal cells, contains gamma-tubulin that initiates the nucleation of microtubules. Other forms of tubulin, such as α-tubulin and β-tubulin, polymerize to form the microtubule's hollow structure. Microtubules are the widest components of the cytoskeleton and are crucial for resisting cellular compression, helping vesicles move through the cell, and separating chromosomes during cell division.
Gamma-tubulin is critical because it provides a template from which the minus ends of microtubules are generated, allowing for the growth of the microtubule polymer. Thus, the correct answer to the question is option 3) Gamma-tubulin.