Cell Membrane Plasma Membrane Cell Membrane 2 layers

Cell Membrane Plasma Membrane

Cell Membrane • 2 layers (bilayer) of phospholipids • Similar to a mayonnaise sandwich – 2 pieces of bread with may stuck together • Each individual phosphoplipid has a – head that is hydrophilic – tail that is hydrophobic

The phospholipid

STOP!! BIG WORDS!!!! • Hydrophobic: Hydro = Water ; Phobic = afraid – The tail of the phospholipid is hydrophobic • Hydrophilic: Hydro = Water ; Philic = loving – The head of the phospholipid is hydrophilic • Millions of these molecules line up together to form a cell membrane!

What is the cell membrane for? Head • Controls material going into the cell • Controls material going out of the cell • Holds the cell together • Able to “talk” with other cells and molecules Phospholipid Tail

Cell Membrane

Cell Membrane

• Membrane looks big? Picture this……. • It would take 10, 000 membranes to equal the thickness of one sheet of paper!!! Cell Membrane

Cell Membrane Proteins • Proteins are stuck throughout the cell membrane • They act as tunnels letting large molecules into and out of the cell

Receptor Molecules • Molecules that help the cell “talk” with other cells or molecules • Must fit together like a puzzle piece

Keep in mind…. . . • Not all substances can pass through the cell membrane!!! Only certain substances when needed……. this is called SELECTIVE PERMEABILITY…. • Know what this means……