2. Plasma membrane
Plasma Membrane (Cell Membrane) :
•The plasma membrane is a lipid-bilayered structure visible
with transmission electron microscopy.
. The principal components of the plasma membrane are lipids
(amphipathic phospholipids and cholesterol), proteins, and
carbohydrates .
3. Physical barrier:
Establishes a flexible
boundary, protects cellular
contents, and supports cell
structure. Phospholipid
bilayer separates
substances inside and
outside the cell
Functions of Plasma Membrane
Selective permeability:
Regulates entry and
exit of ions, nutrients,
and waste molecules
through the membrane
Electrochemical
gradients: Establishes
and maintains an
electrical charge
difference across the
plasma membrane
Communication: Contains receptors that recognize
and respond to molecular signals
5. Types of Transport across Cell Membrane
•Transmembrane Transport
•Vesicular Transport: Endocytosis &
Exocytosis
•Signal Reseption & Transduction
6.
7. 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.
9. Types of Transport Proteins
•Channel proteins are embedded in the cell
membrane & have a pore for materials to cross.
•Carrier proteins can change shape to move
material from one side of the membrane to the
other
