BIOL130 Lecture Notes - Lecture 21: Adherens Junction, Zona Pellucida, Tight Junction
Document Summary
Bacteria, algae, fungi, plants cell wall. What are the common features of the extracellular matrix/cell wall: cross-linked network of filaments - resists stretching and straining forces like steel rods in a building, semi-solid gelatinous matrix (polysaccharides / proteins) - resists compression ( concrete ) Note: needs of plants and animals are very different. Plant cell wall = an extracellular matrix secreted by the plant cell. Plants are sedentary, tissues are fairly rigid, cells are weak and fragile if separated from their walls (called protoplasts") plus they have no intermediate filaments. Driving force for growth of a plant cell is turgor pressure. Orientation of cellulose microfibrils determines the direction of growth of a plant cell (and that organ) Microtubules they provide the template for cellulose synthesis. Form tracks that guide the movement of cellulose synthesizing complexes, which extrude cellulose microfibrils (black lines) to the cell wall. The force of cellulose synthesis drives the movement of the complexes.