Download CELL (PLASMA) MEMBRANE

Science Starter #6 – 10/17/16
• Describe one organelle that is shared between plant and
animal cells and one organelle that only occurs in animal
cells.
• TAKE OUT YOUR CELL COLORING ON YOUR DESK
• TURN IN YOUR CELL EXPLORATION LAB
Notes 3.3
CELL (PLASMA)
MEMBRANE
Chapter 4
Pg. 77-78
Homeostasis
• Balanced internal conditions of cells
• Maintained by cell membrane controlling what
enters or leaves cell.
Cell (Plasma) Membrane
• Function:
• Protective barrier
• Semi-permeable: Regulated transport of molecules in and out of
cell
• Allow cell recognition
• Interact with the environment
Structure
1. Phospholipid Bilayer - Two layers of phospholipids
a) Phospholipid contains:
o
o
b)
2 fatty acid chains that are nonpolar (hydrophobic)
Polar head that contains phosphate (hydrophilic)
Fatty acid tails create a hydrophobic center
Membrane Structure
2. Membrane Proteins-embedded in the lipid layer
a. Integral Proteins: extend through both sides of membrane
• Receptor Proteins: binds to substances outside the
cell
• Transport (channel) Proteins: Aids in moving
substances across membrane
• Glycoproteins (with Carbs): cell identification
Membrane Structure
2. Membrane Proteins-embedded in the lipid layer
b. Peripheral Proteins: only on one side of membrane
Membrane Structure
3. Cholesterol in bilayer for strength