Ch 7.2 Plasma Membrane Yesterday we talked about things all cells have. One of those things was the plasma membrane. Can you remember the other two? Lets

Ch 7.2 Plasma MembraneYesterday we talked about things all cells have. One of those things was the plasma membrane.

Can you remember the other two?

Lets review from yesterday

ProkaryoteEukaryote contains nucleus contains organelles (membrane-bound structures within cell) mostly multicellularTwo Basic Cell Types no nucleus no organelles mostly unicellular very small in size ex. bacteria, archaebacteria ex. plants, animals, yeastALL cells have 1. plasma membrane 2. Ability to break down molcules 3. genetic material

Plasma Membrane- a boundary that controls what leaves and enters the cell.Why is it important to control what leaves and enters the cell???

All prokaryotes and eukaryotes have a plasma membraneSurrounds the cell, providing protection and supportHelps a cell maintain homeostasis, by regulating what enters and leaves the cellSelectively Permeable: Only allows certain materials through

The plasma membrane has 4 main components.Phospholipid BilayerTransport proteins Cholesterols Carbohydrates

Structure of the Plasma MembraneThe plasma membrane is composed of a phospholipid bilayer two layers of phospholipids are arranged tail to tail.

Lipids make up the lipid bilayera. Hydrophobic region (between layers)b. Hydrophilic region (inside and outside the cell)

Hydrophilic = Water Loving Hydrophobic= Water Fearing

Other Components of the Plasma Membrane

Within the Phospholipids there are 3 other things.Do you remember????

Transport proteins Cholesterols Carbohydrates

Other Components of the Plasma Membrane2. Transport proteins - create tunnels through which certain substances enter and leave the cell.

Other Components of the Plasma Membrane3. Cholesterols contribute to the fluidity of the plasma membrane in that they prevent the fatty-acid tails from sticking together.

Other Components of the Plasma Membrane4. Carbohydrates attached to proteins stick out from the plasma membrane and help identify the cell

It looks like this

Fluid Mosaic Modelhttp://www.susanahalpine.com/anim/Life/memb.htm The components of the plasma membrane are in constant motion sliding past each other.The phospholipids in the bilayer create a sea in which other molecules can float, hence fluid and mosaic because there are many components which appear as a pattern or a mosaic.

Ok what???Fluid mosaic model- All the parts of the plasma membrane are moving all the time

Review/Study QuestionsHow does the plasma membrane help maintain homeostasis?What does it mean if something is selectively permeable?What makes up the plasma membrane?Why are the phospholipids arranged like they are?

Plasma Membrane PosterOn your BLANK PAPER complete the following: 1. Title: Plasma Membrane 2. Draw a plasma membrane in color (page 188!)) 3. Label the: * Phospholipids * Proteins * Carbohydrates * Cholestrols * Inside the cell * Hydrophobic areas in BLUE (water fearing!) * Hydrophilic areas in RED (water loving) 4. In the lower RIGHT corner, write your name

Questions on Back

Define plasma membraneWhat is the plasma membranes function?Tell me what the cholesterol doesTell me what the transport protein doesTell me what the carbohydrate does

**A phospholipid molecule is composed of a glycerol backbone, two fatty acid chains, and a phosphate group.*