Day 12 The plasma Membrane (Slide 4, Membrane Components (Phospholipids,…
Day 12 The plasma Membrane
Slide 1, Cell Membrane
The cell membrane is flexible and allows a unicellular organism to move
Slide 3, Functions of Plasma Membrane
Regulate transport in & out of cell (selectively permeable)
Allow cell recognition
Provide anchoring sites for filaments of cytoskeleton
Provide a binding site for enzymes
Interlocking surfaces bind cells together (junctions)
Slide 2, Homeostasis
-Balanced internal condition of cells
-Also called equilibrium
Maintained by plasma membrane controlling what enters & leaves the cell
Aim: What are the functions of the cell (plasma) membrane? What are the structures within the membrane and what do they do?
Slide 4, Membrane Components
(peripheral and integral)
Slide 6, FLUID MOSAIC MODEL
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
The cell membrane is made of 2 layers of phospholipids called the lipid bilayer
Hydrophobic molecules pass easily; hydrophilic DO NOT
Slide 7, Solubility
Materials that are soluble in lipids can pass through the cell membrane easily
Slide 8, Semipermeable Membrane
Small molecules and larger hydrophobic molecules move through easily.
ex: O2, CO2
Ions, hydrophilic molecules larger than water, and large molecules such as proteins do not move through the membrane on their own.
Slide 9, Aquaporins
Protein pores used during OSMOSIS
Slide 10, 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