Final answer:
The cytoskeleton's diagonally arranged protein fibers consist of actin and myosin, forming microfilaments integral to cellular motion and structure. Actin filaments work with myosin to enable muscle contraction and other cell movements.
Step-by-step explanation:
The diagonally arranged protein fibers in the cell's cytoskeleton are composed of actin and myosin. These fibers form the structural framework and contribute to cellular movements, like muscle contraction.
Microfilaments, also known as actin filaments, are composed of two intertwined strands of actin. Together with myosin, these filaments are essential for muscle cells to contract. Actin provides a track for the movement of myosin, which powers the contraction process. Therefore, microfilaments not only establish cell shape but are also involved in various cellular motilities, such as cell division and cytoplasmic streaming.
In contrast, other cytoskeletal elements like microtubules and intermediate filaments serve different functions. Microtubules, composed of tubulin, help in resisting cell compression, moving vesicles through the cell, and separating chromosomes during cell division. Intermediate filaments, made of proteins such as keratin, resist tension and maintain cell integrity in addition to anchoring organelles.