Question

What is ECM?

Answer 1

All cells in tissue form are surrounded by an extracellular matrix or ECM. Both plants and animals have extracellular matrices. In plant cells the cell wall is a type of extracellular matrix. In animals, the ECM can surround cells which help contact the cells on all sides, or as a sheet called the basement membrane that cells ‘sit on’. Cells in animals are joined or linked to each other by cell adhesion molecules (CAMs) at the cell surface.

Complete solution:
The extracellular matrix or ECM is a three-dimensional network consisting of extracellular macromolecules and minerals, which includes collagen, enzymes, glycoproteins and hydroxyapatite that provide structural and biochemical support to surrounding cells.
Because multicellularity evolved independently in different multicellular lineages, the ECM composition varies between multicellular structures.
The main functions of ECM are cell adhesion, cell-to-cell communication and differentiation are common functions of the ECM.
The extracellular matrix (ECM) of animal cells includes the interstitial matrix and the basement membrane. Interstitial matrix is present between various animal cells between the intercellular spaces.
Gels of fibrous proteins and polysaccharides fill the interstitial space and they act as a compression buffer against the stress placed on the ECM. Basement membranes are sheet-like structures that are depositions of an extracellular matrix on which various epithelial cells rest.
The plant extracellular matrix includes cell wall components, like cellulose, in addition to more complex signaling molecules.
Some single-celled organisms adopt multicellular biofilms in which the cells are embedded in an extracellular matrix composed primarily of extracellular polymeric substances (EPS).
Components of the extracellular matrix or ECM are produced intracellularly by resident cells and secreted into the ECM via exocytosis. Once they are secreted, they aggregate with the existing matrix. The ECM is composed of an interlocking mesh of fibrous proteins and glycosaminoglycans.

Note:
The ECM can serve many functions, such as it provides support to the cell, it segregates tissues from one another, and regulates intercellular communication. The ECM also regulates a cell's dynamic behavior, other than this it also sequesters a wide range of cellular growth factors and acts as a local store for them. Formation of ECM is essential for growth,wound healing and fibrosis.