Extracellular Matrix

ECM

Components outside the cell that provide structure or biochemical support

ECM types in bacteria

1. Slime layer

2. Cell Wall

3. Biofilm

ECM types in plants

Cell wall. Components include: Cellulose, hemicellulose, and pectin. There is also the middle lamella, which is made of pectin and helps plant cells stick together.

Some plants have a secondary cell wall between primary cell wall and plasma membrane. It is made of lignin and is much stronger than primary cell walls. It is commonly found in trees.

Communication between cells: Cell Junctions

Join adjacent cells and allow them to share material

Plasmodesmata

Cell junctions found in adjacent plants that allow for the sharing of cytoplasmic material

Gap Junctions

Cell junctions in adjacent animal cells. They contain connexion proteins that allow for the sharing of monomers, ions, and water

Forms of ECM in animal cells: Basement membrane

Thin, sheetlike layers that give support for epithelial, muscle, and nerve cells. They are made of basal lamina and are located on the basal side of the cell. The apical side is the opposite side of the basal side.

Forms of ECM in animal cells: Interstitial space

A 3D network in which cells are suspended. Present in extracellular spaces.

It contains fibroblasts that secrete:

1. Collagen - the most abundant protein in body. Main component of ECM that gives the cell the ability to stretch, structural support, and elasticity.

2. Elastin - Provides flexibility and allows body components to resume shape after stretching.

3. Proteoglycan - Small core of protein with numerous carbohydrate chains branching off. Aid in cell signaling and structural support.