Warmup Download the Popplet App Create a New Popplet titled: “Gummi Bear Lab – Last Name” Set Up Popplet as follows:

Warm Up for 10/4: In a sentence or two, explain why the oil can’t “mix” with the water molecules.

Cell Membrane The cell membrane is a double-layered sheet called a lipid bilayer. This layer forms a strong barrier between the cell and its surroundings. Said to be semipermeable or selectively permeable

3 Main Functions of Cell Membrane Boundary – Separates the cells from each other and their environment

3 Main Functions of Cell Membrane Regulator – Allowing the transport of some substances into and out of the cell, but not others Semi- or Selectively Permeable

3 Main Functions of Cell Membrane Signaling – allows cells to signal other cells. Cells have proteins called receptors that bind to signaling molecules and initiate a physiological response. Example: Hormones Different receptors are specific for different molecules. Receptors can also respond directly to light or pressure.

Parts of the Cell Membrane Phospholipid Head – Creates the outside of the membrane Polar Hydrophilic – Water Loving

Parts of the Cell Membrane Phospholipid Tail – Creates the inside of the membrane, causes membrane to stay together Nonpolar Hydrophobic – Water Fearing

Parts of the Cell Membrane Integral Proteins – Completely inside the lipid bilayer Control entry and removal of specific substances Channel and carrier proteins

Parts of the Cell Membrane Peripheral Proteins – Bound to the exterior side of the membrane Has various functions

Parts of the Cell Membrane Cholesterol – Help keep the fluidity of the membrane Fluid Mosaic Model

Parts of the Cell Membrane Carbohydrate Chains – Serve as the “fingerprints” of the cell Glycoproteins and Glycolipids allow the cells to recognize each other

4 Main Functions of Cell Membrane Recognition – help cells identify self from non-self *Glycoproteins and Glycolipids allow the cells to recognize each other*

Picture of Cell membrane