BIL 150 Chapter 7-10: BIL 150 Chapter 7-10
Document Summary
The plasma membrane that surrounds the cell can be considered the edge of life, the boundary that separates a living cell from its surroundings and controls all inbound and outbound traffic. Selectively permeable: allows some substances to cross it more easily than others. Membranes are mainly comprised of lipids and proteins, but carbohydrates are also important. The most abundant lipids in most membranes are phospholipids. The ability of phospholipids to form membranes is innate in their molecular structure. Molecule , meaning it has both a hydrophilic (water-loving) region and a hydrophobic (water-fearing) region. Like membrane lipids, most membrane proteins are amphipathic ; these proteins can reside in the phospholipid bilayer with their hydrophilic regions protruding. This molecular orientation maximizes contact of hydrophilic regions of proteins with water in the cytosol and extracellular fluid, while providing their hydrophobic parts with a nonaqueous environment. The structure below shows the arrangement of these proteins.
