Lecture on Cytoskeleton: Structure of the Cell

Overview of Cytoskeleton

The cytoskeleton is a network of protein fibers within the cell.
Functions:
- Provides cell structure and shape (like a skeleton).
- Offers motility and ability to resist forces and pressures.
- Acts as a highway system for intracellular transport and organization of organelles.

Characteristics:
- Thinnest type of protein fiber.
- Diameter: 6-7 nanometers.
- Composed of actin.
- Contains a positive and a negative end.
Functions:
- Involved in cell contraction (e.g., muscle cells).
- Provides tensile strength to resist pulling forces.
- Stabilizes cell shape and structure.
- Involved in processes such as muscle contraction (through interaction with myosin), phagocytosis, and cytoplasmic streaming.

Characteristics:
- Intermediate thickness, about 10 nanometers.
- Composed of various proteins.
- Found in cytoplasm and nucleus (forms nuclear lamina).
Functions:
- Provides tensile strength and stability.
- Maintains cell shape and structure.
- Involved in binding cells together.

Characteristics:
- Largest and strongest type of fiber.
- Diameter: 23 nanometers.
- Composed of tubulin (alpha and beta forms)
- Hollow, tube-like structure.
- Positive end grows, negative end at Microtubule Organizing Center (MTOC) known as centrosome in animal cells.
Functions:
- Provides compressive strength.
- Involved in cell division by forming the mitotic spindle.
- Facilitates intracellular transport as a cellular highway.
- Forms structures like cilia and flagella.

The cytoskeleton consists of three types of fibers: microfilaments, intermediate filaments, and microtubules.
Each type of fiber has unique structures and functions that contribute to the cell's structural integrity, movement, and function.
Understanding the cytoskeleton is crucial for comprehending cell dynamics and function.