BIO251H1 Study Guide - Midterm Guide: Cell Wall, Middle Lamella, Rechargeable Battery
Document Summary
Primary cell wall: composed of cellulose microfibrils in a matrix. Rigid structure that allows for the build up of substantial hydrostatic pressure within the cell. Cellulose microfibrils are synthesized by rosette enzymes located in the plasma membrane in the cell wall. They take udp and form long chains of glucose (2000-25000 glucose residues form 1-5 micron chain in length). Cellulose fibers are formed by the hydrogen bonds occurring between the rows of glucose molecules. Single strand of cellulose macrofibril microfibril (primary component) micelle (crystalline-like structure, strong) Middle lamella: made up of pectin, which acts like cement in holding two cell walls together. Canals: plasmodesmata connect cells together for communication and transportation. Secondary cell walls: majority of cells have a secondary cell wall, but some reproductive cells may not. Secondary cell wall is always adjacent to the plasma membrane. Three-layered wall in which the orientation of cellulose macrofibrils are laid down in alternating patterns to provide optimal strength.
