1. Chapter 17
Beyond the Cell: Extracellular Structures, Cell Adhesion, and Cell Junctions

2. Beyond the Cell: Extracellular Structures, Cell Adhesion, and Cell Junction
The Extracellular Matrix of Animal Cells
Cell-Cell Recognition and Adhesion
Cell Junctions
The Plant Cell Surface 

3. The extracellular matrix (ECM) of animal cells functions in division, support, adhesion, and movement
In many cells, fibronectins in the ECM connect to integrins, intrinsic membrane proteins.
The integrins connect the ECM to the cytoskeleton.

4. Collagens Are Responsible for the Strength of the Extracellular Matrix
In plants, fungi, algae and prokaryotes, the extracellular structure is called a cell wall.
Lacking cell walls, animals cells do have an elaborate extracellular matrix (ECM).
The primary constituents of the extracellular matrix are glycoproteins, especially collagen fibers, embedded in a network of proteoglycans.

5. Proteoglycans and Adhesive Glycoproteins Anchor Cells to the ECM
Either proteoglycan or collagen may bind to specific receptor proteins on the outer surface of the plasma membrane.
Two most common kinds of adhesive glycoprotein are fibronectins and laminins
In many cells, fibronectins in the ECM connect to integrins

6. Beyond the Cell: Extracellular Structures, Cell Adhesion, and Cell Junction
The Extracellular Matrix of Animal Cells
Cell-Cell Recognition and Adhesion
Cell Junctions
The Plant Cell Surface 

7. Beyond the Cell: Extracellular Structures, Cell Adhesion, and Cell Junction
The Extracellular Matrix of Animal Cells
Cell-Cell Recognition and Adhesion
Cell Junctions
The Plant Cell Surface 

8. Gap Junctions
Communicating junctions provide cytoplasmic channels between adjacent cells.
Special membrane proteins surround these pores.
Salt ions, sugar, amino acids, and other small molecules can pass.
In embryos, gap junctions facilitate chemical communication during development.