Plasma Membrane-Gateway to the Cell

Page
1

Slide 1

The Plasma Membrane -

Gateway to the Cell

Slide 2

Photograph of a Cell Membrane

Slide 3

Cell Membrane

The cell membrane is flexible and allows a unicellular organism to move

Slide 4

Homeostasis

Balanced internal condition of cells

Also called equilibrium

Maintained by plasma membrane controlling what enters & leaves the cell

Slide 5

Functions of Plasma Membrane

Protective barrier

Regulate transport in & out of cell (selectively permeable)

Allow cell recognition

Provide anchoring sites for filaments of cytoskeleton

Slide 6

Functions of Plasma Membrane

Provide a binding site for enzymes

Interlocking surfaces bind cells together (junctions)

Contains the cytoplasm (fluid in cell)

Slide 7

Structure of the Cell Membrane

Slide 8

Phospholipids

Cholesterol

Proteins (peripheral and integral)

Carbohydrates (glucose)

Membrane Components

Slide 9

Slide 10

Phospholipids

Make up the cell membrane

Contains 2 fatty acid chains that are nonpolar

Head is polar & contains a –PO4 group & glycerol

Slide 11

Fluid mosaic model

FLUID- because individual phospholipids and proteins can move side-to-side within the layer, like it’s a liquid.

MOSAIC- because of the pattern produced by the scattered protein molecules when the membrane is viewed from above.

Slide 12

Cell Membrane

Polar heads are hydrophilic “water loving”

Nonpolar tails are hydrophobic “water fearing”

Makes membrane “Selective” in what crosses

Slide 13

Slide 14

Cell Membrane

Hydrophobic molecules pass easily; hydrophilic DO NOT