1. Microfilaments (Actin Filaments):
- Thin, thread-like structures made of actin proteins.
- Form a dense meshwork just beneath the cell membrane.
- Provide structural support, maintain cell shape, and facilitate cellular processes like cell division, cell movement, and phagocytosis.
2. Microtubules:
- Hollow, cylindrical structures made of tubulin proteins.
- Radiate from the centrosome, which serves as the cell's microtubule-organizing center.
- Provide structural stability, act as intracellular highways for organelle transport, and play crucial roles in cell division (forming the mitotic spindle) and determining cell shape.
3. Intermediate Filaments:
- Tough, rope-like structures made of various types of intermediate filament proteins.
- Form a scaffold that helps maintain cell shape and provides mechanical strength.
- Different types of intermediate filaments are found in different cell types, contributing to tissue-specific properties.
In addition to these cytoskeletal components, some animal cells may also have a cell wall, which is a rigid structure surrounding the cell membrane. The cell wall, commonly found in plant cells, provides additional support and protection. In animal cells, however, the cell wall is typically absent, allowing for more flexibility and dynamic cellular processes.