Cell Membrane: Gateway to the World
Three Components: Phospholipid Bilayer, Integral Proteins,
Glycolipids/Glycoproteins
Physpholipid Bilayer: Two layers of lipid molecules
consisting of a hydrophobic tail and a hydrophilic head.
 Hydrophilic head: made of phosphate and glycerol,
water-liking
 Hydrophobic tail: made of lipids, water-disliking
Integral Proteins:
 Two Types:
o Protein Channels: allow large molecules like
glucose access to the cell.
o Protein Pumps: pump charged ions across the
membrane to maintain homeostasis
Glycolipids/Glycoproteins: complex sugar molecule found on
the exterior of the cell, help the cell membrane to recognize
and communicate with other cells
Functions:
 Barrier between interior and exterior of the cell
 Supports the cell
 Protects the cell
 The glucose compounds serve as chemical identification
markers (cell adhesion, cell communication, recognition)
 Allows certain molecules in and restricts other molecules
(semi-permeable)