Transcript The plasma membrane

The plasma (Cell) membrane
• Cell Membrane (Plasma Membrane): forms
a boundary between a cell and the outside
environment.
Maintaining balance
• Cells must keep a balance inside
the cell and be able to eliminate
wastes.
• The plasma membrane does this by
controlling the passage of materials
into and out of the cell.
Maintaining balance
• Selective permeability means that
the plasma membrane is able to
allow some materials to pass while
keeping others out.
Structure
• The cell membrane is a phospholipid
bilayer.
• It contains two layers of several
phospholipids/ lipid molecules with proteins
embedded.
• A phospholipid is composed of three basic
parts
Phospholipid
Cell Membrane-fluid mosaic
model
The plasma (cell) membrane
The lipid bilayer
• The phosphate group is attracted to
water (hydrophilic
).This means
polar.
• Fatty acid tails don’t like water and are
repelled by water (hydrophobic
).
This means non-polar.
The membrane proteins
• The proteins determine which
particles can pass and act as
markers and receptors to signal
molecules where they can go or
what they can do.