Final answer:
Microtubules, composed of 13 polymerized α-tubulin and β-tubulin dimers, form a hollow cylinder with a diameter of about 25 nm and are the widest components of the cytoskeleton, vital for maintaining cell shape, intracellular transport, and cell division.
Step-by-step explanation:
The tubulin subunits that make up microtubules consist of polymerized dimers of α-tubulin and β-tubulin. Microtubules are small hollow tubes that play several important roles in the cell, such as preserving cell shape, enabling vesicle movement, and assisting chromosome segregation during cell division. As part of the cytoskeleton, each microtubule is composed of 13 these tubulin dimers that form the hollow, 25 nm diameter cylinder required for their functions.
Microtubules are integral to the structure and function of cilia and flagella, and with the help of motor proteins like dynein and kinesin, they are responsible for the intracellular transport of organelles and vesicles. These dynamic structures can rapidly assemble and disassemble in response to cellular needs. The hollow construction of microtubules, and their composition of tubulin dimers, is a critical feature for their scaffolding and transport roles within the cell.