Final answer:
The proteins that support the cytoplasmic side of the cell by a network of filaments are microfilaments of the cytoskeleton, which are composed of actin and are involved in maintaining cell shape and facilitating movement.
Step-by-step explanation:
The proteins that are mostly on the cytoplasmic side of the cell and support that side by a network of filaments are part of the cytoskeleton. This network includes microfilaments, intermediate filaments, and microtubules. Specifically, microfilaments (also known as actin filaments), are composed of two intertwined strands of a globular protein called actin. They are the thinnest fibers in the cytoskeleton and play a crucial role in maintaining the cell's shape, facilitating cellular movement, and anchoring organelles. Peripheral proteins are also found on the cytoplasmic side of the cell membrane, but they are not involved in the cytoskeletal structure. Rather, these proteins can be associated with the plasma membrane and can function in various processes such as signaling or maintaining the cell's shape by connecting to the cytoskeleton.