Plasma Membrane-Gateway to the Cell

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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