Chapter 5 Membrane Structure and Function part I

Chapter 5 Membrane Structure and Function part I Page ref. 84 -86

Memorize these words!!! § § § inter – within ie. Hilo to Honolulu intra – between, among ie. Hilo to Kona extra – outside of (extracellular would be outside the cell) § glyco – containing sugar/carbohydrates (sugar-coated)

The fluid-mosaic model of the plasma membrane § The cell membrane is a fluid, phospholipid bilayer in which protein molecules are either fully or partially embedded. (see fig. 5. 1 and 5. 2)

Plasma membrane functions § to separate the internal from external environment of the cell § Regulates materials entering and leaving the cell. § Helps the cell, in turn the organism, maintain homeostasis

Plasma membrane structure § Made up of a phospholipid bilayer § Phospholipid: a molecule with a hydrophilic (waterloving) head and a hydrophobic (waterfearing) tail

Plasma Membrane Components § Cholesterol: a lipid found in bilayer, for strength of membrane § Proteins: peripheral (inside surface of membrane) or integral (embedded in membrane) § Some integral proteins protrude from one surface of bilayer, some protrude from both (transmembrane) § Phospholipids and proteins can have attached carbohydrate (sugar) chains. These are called glycolipids, and glycoproteins, respectively

Carbohydrate Chains § Carbohydrate chains of proteins in animal cell give cell a “sugar coat” called the glycocalyx. § Functions of the glycocalyx include protection of the cell, enables cells to adhere to one another, reception of signal molecules, and for cell-to-cell recognition

Fluidity of Plasma Membrane § Membrane fluidity critical to it’s functioning § At body temperature, it has the consistency of olive oil § This allows the cell to do all it needs to do – it makes the cell pliable

Homework § § Due Thursday All vocab AND Reviewing chapter - #1 -3 Testing yourself 2, 3, 11, 12, 13, 14