The cytoskeleton is a network of protein fibers that acts as a kind of scaffolding, giving shape and protection to both prokaryotic and eukaryotic biological cells. However this minute structural system does much more than keep the cell in its proper shape.
Role of the Cytoskeleton
The versatile cytoskeleton enables some cell motion, through the use of cellular appendages such as flagella and cilia. The fibers also play an important role in intra-cellular transport; the movement of vesicles and organelles around within the cell. And when it is time expand operations and undergo cell division, components of the cytoskeleton help sort out the genetic material and elongate the cell before it splits in two.
Microtubules, Intermediate Filaments & Microfilaments
The cytoskeleton consists of three types of protein fibers: microtubules, intermediate filaments and microfilaments.
Microfilaments
These subunits of the cytoskeleton are twisted double strands of the protein actin. Microtubule filaments are responsible for cell movement and shape, as well as simply holding the cell together.
Intermediate Filaments
This structural component is made of subunits woven together into rope-like strands. Although the structure varies depending on the type of tissue that the cell is part of, intermediate filaments help maintain cell shape, support nerve cell extensions, and attach cells to each other.
Microtubules
Tiny tubes, made up of spiraling tubulin subunits, aid in chromosome movement, transport of organelles, and the movement of cellular appendages.
These are the “highways” along which the organelles travel and are conveyed. And microtubule roads are amazingly dynamic. Assembled at one end while being disassembled at the other, microtubules give the impression of a forward direction of movement when in fact there is none. Microtubules may work alone, or join with other proteins to form more complex structures called cilia, flagella or centrioles.
Centioles and Centrosomes
Centriole
A centriole is a barrel-shaped organelle found in most eukaryotic cells, though absent in higher plants and fungi. Each centriole is composed of nine triplets of microtubules.
Centrosome
A centrosome is an associated pair of centrioles, arranged perpendicularly, and function like little microtubule factories. During animal cell division, the centrosome divides and the centrioles replicate (make new copies). The result is two centrosomes, each with its own pair of centrioles. The two centrosomes move to opposite ends of the cell’s nucleus, and produce microtubules that grow into a "spindle" responsible for moving the replicated chromosomes to opposite ends of the cell and ultimately, once the cell splits, into the two daughter cells.
Plant cells also have centrosomes, which function as microtubule factories, much like animal cell centrosomes, but do not have centrioles or play a role in plant cell division.
Additional Cell Biology Information
For more useful images and resources on how living cells work, see the SPO Virtual Cell Biology Classroom or the interactive tutorials on Cells Alive!
Photo Credit
Fluoresced Cells Showing Cytoskeleton and Nucleus: Endothelial cells under the microscope. Nuclei are stained blue, microtubles are marked green and actin filaments are labelled red. National Institutes of Health image, US Government, appearing in WikiMedia.
Role of the Cytoskeleton
The versatile cytoskeleton enables some cell motion, through the use of cellular appendages such as flagella and cilia. The fibers also play an important role in intra-cellular transport; the movement of vesicles and organelles around within the cell. And when it is time expand operations and undergo cell division, components of the cytoskeleton help sort out the genetic material and elongate the cell before it splits in two.
Microtubules, Intermediate Filaments & Microfilaments
The cytoskeleton consists of three types of protein fibers: microtubules, intermediate filaments and microfilaments.
Microfilaments
These subunits of the cytoskeleton are twisted double strands of the protein actin. Microtubule filaments are responsible for cell movement and shape, as well as simply holding the cell together.
Intermediate Filaments
This structural component is made of subunits woven together into rope-like strands. Although the structure varies depending on the type of tissue that the cell is part of, intermediate filaments help maintain cell shape, support nerve cell extensions, and attach cells to each other.
Microtubules
Tiny tubes, made up of spiraling tubulin subunits, aid in chromosome movement, transport of organelles, and the movement of cellular appendages.
These are the “highways” along which the organelles travel and are conveyed. And microtubule roads are amazingly dynamic. Assembled at one end while being disassembled at the other, microtubules give the impression of a forward direction of movement when in fact there is none. Microtubules may work alone, or join with other proteins to form more complex structures called cilia, flagella or centrioles.
Centioles and Centrosomes
Centriole
A centriole is a barrel-shaped organelle found in most eukaryotic cells, though absent in higher plants and fungi. Each centriole is composed of nine triplets of microtubules.
Centrosome
A centrosome is an associated pair of centrioles, arranged perpendicularly, and function like little microtubule factories. During animal cell division, the centrosome divides and the centrioles replicate (make new copies). The result is two centrosomes, each with its own pair of centrioles. The two centrosomes move to opposite ends of the cell’s nucleus, and produce microtubules that grow into a "spindle" responsible for moving the replicated chromosomes to opposite ends of the cell and ultimately, once the cell splits, into the two daughter cells.
Plant cells also have centrosomes, which function as microtubule factories, much like animal cell centrosomes, but do not have centrioles or play a role in plant cell division.
Additional Cell Biology Information
For more useful images and resources on how living cells work, see the SPO Virtual Cell Biology Classroom or the interactive tutorials on Cells Alive!
Photo Credit
Fluoresced Cells Showing Cytoskeleton and Nucleus: Endothelial cells under the microscope. Nuclei are stained blue, microtubles are marked green and actin filaments are labelled red. National Institutes of Health image, US Government, appearing in WikiMedia.
