Chapter 5 Membrane Structure and Function part I Page ref

Memorize these words!!! inter – within ie. Hilo to Honolulu inter – within ie. Hilo to Honolulu intra – between, among ie. Hilo to Kona intra – between, among ie. Hilo to Kona extra – outside of (extracellular would be outside the cell) extra – outside of (extracellular would be outside the cell) glyco – containing sugar/carbohydrates (sugar-coated) 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) 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 to separate the internal from external environment of the cell Regulates materials entering and leaving the cell. Regulates materials entering and leaving the cell. Helps the cell, in turn the organism, maintain homeostasis Helps the cell, in turn the organism, maintain homeostasis

Plasma membrane structure Made up of a phospholipid bilayer Made up of a phospholipid bilayer Phospholipid: a molecule with a hydrophilic (water- loving) head and a hydrophobic (water- fearing) tail

Plasma Membrane Components Cholesterol: a lipid found in bilayer, for strength of membrane Cholesterol: a lipid found in bilayer, for strength of membrane Proteins: peripheral (inside surface of membrane) or integral (embedded in 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) 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 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. 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 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 its functioning Membrane fluidity critical to its functioning At body temperature, it has the consistency of olive oil 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 This allows the cell to do all it needs to do – it makes the cell pliable

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