Extracellular Matrix (ECM)
Layer of protein and polysaccharide, commonly referred to as glycoproteins, found outside the plasma membrane of eukaryotic cells. Sometimes referred to as the glycocalyx
proteins and polysaccharides, produced by the cells
3 Main Types of Glycoproteins
Fibronectin, Collagen, Proteoglycan
attache the ECM to the plasma membrane of the cell. More specifically, they bind to receptor proteins called integrins, which are embedded in the plasma membrane. The integrins are bound to microfilaments of the cytosleleton on the cytoplasmic side of the membrane.
Most abundant of the glycoproteins in the ECM, bound to the fibronectin and also is in a network of proteoglycan fibers.
Glycoproteins that have a very high Carbohydrate contents - up to 95%
Functions of the ECM
Strengthens the cell surface, promotes attachment b/w cells, coordinates behavior of cells within a tissue, and regulation of cell function.
How does the ECM regulate Cell function?
Signals from the ECM can be transmitted into the cytoskeleton by way of Integrins. The integrins "integrate" signals. It is thought that these messages can influence the activity of genes in the nucleus.
The cells interior
Cilia and Flagella
Projections on the surface of the cell that contains cytoplasm and are and extension of the plasma membrane. They are anchored to the plasma membrane by a basal body.
Internal Cilia and Flagella
Consists of 9 pairs of microtubules and 2 central microtubules (9+2 arrangement)
Long hollow tubes composed of the protein Tubulin
Protein that holds the outer doublets and central microtubules together
Dynein + ATP
Responsible for the movement of the cilia and the flagella
projections are numerous and short, beating patterns have a back and forth motion that move the cell in a direction that is perpendicular to the axis of the cilium.
Projections are few and long, has an undulating motion that drive the cell in teh same direction as the axis of the flagellum.
Functions of Cilia
Movement of the cell, also serves as a non-specific defense mechanism
Example of how Cilia serves in defense
In our respiratory system the cilia serve as a mechanical barrier to microorganisms by moving foreign material up toward the mouth
Function of Flagella
Movement of the cell