The Cytoskeleton, CELL SHAPE AND MOTILITY

JAN MUHAMMAD

What is Cytoskeleton?

Cytoplasm contains a complex network of filaments and microtubules which form a structural framework known as CYTOSKELETON.

=Cells need (cyto) skeleton to:*create shape*change shape*allow movement

Dynamic!

Cytoskeleton: The skeleton and muscle of a cell

Three main kinds of fibers make up the CYTOSKELETON:

● MICROFILAMENT● INTERMEDIATE FILAMENT● MICROTUBULES

MICROFILAMENT

● Thinnest filament present in the cytoskeleton in cytoplasm of eukaryotic cell.

● Give the cell its shape and enable cell movement

MICROFILAMENT

FUNCTIONS OF MICROFILAMENT

Microfilaments play a role in structure, cell motility, and cell division. Microfilaments are made of actin, and thus are involved in muscle contraction as well as cell division.

INTERMEDIATE FILAMENTS

● Made of variety of proteins, including keratin, desmin and vimentin

● 8 to 12 nanometer

● Composed of two anti parallel dimer

INTERMEDIATE FILAMENTS

FUNCTIONS OF INTERMEDIATE FILAMENT

● provide mechanical support for the plasma membrane where it comes into contact with other cells or with the extracellular matrix

● intermediate filaments do not participate in cell motility.

MICROTUBULES

● Microtubules, the thickest fibers, are hollow rods about 25 microns in diameter. ● Microtubule fibers are made up of the globular protein, tubulin, and they grow or shrink as more tubulin molecules are added or removed.

MICROTUBULES

Microtubules participate in the intracellular transport of organelles and vesicles.

FUNCTIONS OF MICROTUBULES

Microtubules are the central structural supports in cilia and flagella.The locomotive appendages of cell

Cilia● minute hairlike organelles, identical in structure to flagella, that line the surfaces of certain cells and beat in rhythmic waves, providing locomotion to ciliate protozoan and moving liquids along internal epithelial tissue in animals.

CILIA

FLAGELLA

● A slender threadlike structure, esp. a microscopic whiplike appendage that enables many protozoa, bacteria, spermatozoa, etc., to swim.

FLAGELLA

FLAGELLA

Thank you