BI110 Lecture Notes - Lecture 8: Tight Junction, Middle Lamella, Extracellular Matrix
Document Summary
Makes up 40% of protein in human body. Protein and carbs linked together (95% carbs) Tight junction: watertight connections b/w neighboring cells, helps body to retain water. Desmosomes (anchoring junctions: proteins on two adjacent cells, like rivets, connect cells together; connected to intermediate laments. Gap junctions: channels b/w cells that allow movement of water and small molecules b/w animal cells. Plant cell wall: protects cell, maintain cell structure, prevents too much water to enter, cell wall is rigid, primary component of cell wall = cellulose, middle lamella sits b/w two cell walls holding them together(made of pectin(carbs)) Plasmodesmata: cytoplasmic channels b/w two adjacent cells, allows transport of material b/w cells, shr= signaling molecule, controls gene expression and can be transported through plasmodesmata into endodermal cell, never reaches cortex. Importance of selectively permeable membranes: cells and organelles need barrier to separate internal and external content, barrier must have following qualities.
