Question

Write a term paper on Extracdllular matrix and cytoskeleton

Answer 1

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Extracellular Matrix

The extracellular matrix is the matrix which contains extracellular molecules secreted by the supporting cells and it provides structural and biochemical support to the surrounding cells. It is abbreviated as ECM. The ECM can be assumed as soup or a gel mixture of water, polysaccharides, fibrous proteins, and proteoglycans. The proteoglycans are the hybrid cross of a protein and sugar. Its structure have a protein core part and several long sugar chains are surrounding it.

Extracellular Matrix components

The main components of the ECM is water, fibrous proteins and proteoglycans. The proteins are act as macromolecules and the most common proteins found in the ECM are collagens, elastins, fibrionectin and laminins. These protein molecules provide sturdiness to the ECM and help to sustain the ECM in environmental pressure without causing any deformity in its actual structure. The concentration of collagen protein is found maximum in ECM. It provides tensile strength and facilitate cell-to- cell adhesion and migration. Whereas elastin provides the ability to recoil and stretching of ECM without breaking. Actually elastin protein bind and physical cross linked with the collagen protein and make collagen protein stretchable up to a limited extent. The other protein is fibronectin which is secreted by the fibroblasts, the fibronectin regulates division and specialization in many tissue types. It also help in the positioning of cells inside the matrix. The next important ECM protein is known as Laminin. This protein assembled it self into sheet like protein networks and act as glue which associates various type of tissues together. The laminin is mostly present at the junctions where connective tissue meet muscle, nerves and other tissues.

ECM have following functions:

1. ECM acts as cushion or filler that placed between the tightly packed cells in a tissue . 2. Along with the filling the gap between the cells it also retain a particulate water level and homeostatic balance. 3. It provides the morphological shape to the tissue. 4. it also help in the cell to cell interaction and help in the maintaing the signaling pathways. 5. It also help in the cellular growth and help in wound healing. 6. It also help in the hardening of the bones because it contains several essential minerals which are necessary for the bone hardening.

Cytoskeleton

Cytoskeleton is dense network of filament and tubules which spreads in whole cells, through the cytoplasm. It is found in all sells and it is made up of proteins whose composition varies from organism to organism. The major role of cytoskeleton is to provide shape, organizes other organelles, molecule transport , cell signaling as well as cell division.

Structure of the Cytoskeleton

The major components of cytoskeleton are 3 filaments known as microfilaments, intermediate filaments and microtubules.

Microfilaments

These are mostly made up of Actin protein so also known as actin filaments. The microfilaments are spiral in shape having two filaments bound together in spiral shape. The microfilament are about 7nm in thickness and known as the thinnest filament of the cytoskeleton. The microfilaments have several functions such as it help in cytokinesis, help in cell motility, cytoplasm streaming, muscle contraction

Intermediate Filaments

The intermediate filaments are known as intermediate because they are between th esize of microfilaments and microtubules. Their size is about 8-12 nm wide.. The intermediate filament protein composition is as follows: Keratin,vimentin, desmin, and lamin. Except lamin all other intermediate filaments are found in cytoplasm whereas the lamin found in nucleus which support the nuclear envelop to provide proper shape to nucleus. The main function of intermediate filaments is to maintain cell shape, bear tension and provide structural support to the cell.

Microtubules

These are the largesttype of cytoskelton , its size is about 23 nm. They have hollow tube shape and made up of alpha and beta tubulin. The microtubules in an animal cell arise from a cell organelle called the centrosome, which is a microtubule organizing center (MTOC).The microtubules help in the molecule transportation within the cells and also plays a major role in the cell wall formation in plant cells.

Function of the Cytoskeleton

1. It provides cell shape. 2. It helps to cell movements. 3. It organizes the cell organelles at a particular place.4. Cytoskeleton help in the chromosome movement during cell division.