1. The Plasma (Cell) Membrane Structure and Function

2. 4(B) Investigate and explain cellular processes, including homeostasis, energy conversions, transport of molecules, and synthesis of new molecules. 11(A) Describe the role of internal feedback mechanisms in the maintenance of homeostasis. Essential Questions How does a cell’s plasma membrane function? What are the roles of proteins, carbohydrates, and cholesterol in the plasma membrane? The Plasma Membrane Copyright © McGraw-Hill Education

3. The Plasma Membrane Copyright © McGraw-Hill Education Plasma Membrane Functions Thin, flexible boundary between the cell and its environment needed for homeostasis Allows nutrients into the cell, and allows waste to leave the cell Provides structural support to the cell Plays role in cell communication Selective Permeability The plasma membrane controls the movement of substances into and out of the cell. Controls the amount of a substance entering the cell and controls the amount of a substance leaving the cell

4. Called: Consists of: Nonpolar zone creates barrier & makes membrane selectively permeable Plasma Membrane Structure

5. Called: Consists of: Contain polar & nonpolar regions Polar head Nonpolar Tails Attracted to H 2 O hydrophilic Hates H 2 O hydrophobic Nonpolar zone creates barrier & makes membrane selectively permeable Plasma Membrane Structure Phospholipids Proteins Cell Surface Proteins Arranged as 2 layers (bilayer) Tails in, heads out Channel Proteins doughnut shaped act as gates to allow molecules with a “key” get in Marker Proteins elongated w/chains of Carbs attached “name tags” of cell- determine cell ID recognizes foreign invaders Receptor Proteins boulder shaped transmit info from outer environment to inner & vice versa

6. Plasma Membrane The plasma membrane is composed of the phospholipid bilayer. A phospholipid molecule is composed of a glycerol backbone, two fatty acid chains, and a phosphate group. The Plasma Membrane Copyright © McGraw-Hill Education

7. Fluid Mosaic Model Plasma membrane structures can move and change position; “fluid.” The phospholipid bilayer allows other molecules to “float” in the membrane, creating a pattern; “mosaic”. Fluid Mosaic Model Animation Other Components Proteins Cholesterol Carbohydrates The Plasma Membrane Copyright © McGraw-Hill Education

8. Mosaic Tile

9. Proteins The Plasma Membrane Copyright © McGraw-Hill Education Transmit signals inside the cell Act as a support structure Provide pathways for substances to enter and leave

10. Cholesterol The Plasma Membrane Copyright © McGraw-Hill Education Prevents fatty acid tails from sticking together