Plasma Membrane

Structure  Phospholipid bi-layer

Structure  Phosphate Head – Hydrophilic  Lipid Tail – Hydrophobic  Glycoprotein/Glycolipids – Cell markers  Carrier Protein – Passive and Active

Function of the Plasma Membrane  - selectively permeable membrane  - allows for communication between cells  - provides the cell with a specific “marker”

Carrier Protein  Passive Channel – Leakage channel  Active Channel – Open and close to let larger molecules through  - Uses Cellular energy (ATP)  Channel Protein Channel Protein Channel Protein

Plasma Membrane  Construction of the Cell Membrane - Learning Ac - Flash Player Installation Construction of the Cell Membrane - Learning Ac - Flash Player Installation Construction of the Cell Membrane - Learning Ac - Flash Player Installation

Particle Theory  1. All matter is made of particles  2. The particles are in constant motion (Kinetic motion of particles)  3. The closer the particles are together, the greater the attractiveness between them.

Particle Theory  Solids – definite shape and volume  Liquids – definite volume but indefinite shape  Gases – indefinite shape and volume  Matter Matter

Cellular Transport  Passive Transport – use no cellular energy  A) Diffusion  B) Osmosis  C) Facilitated Diffusion

A. Diffusion  - Movement of particles from an area of High concentration to an area of Low concentration  - Particles will move until they are evenly distributed in an Equilibrium  - Particles continue random movement, but it has no affect on the equilibrium  Diffusion Diffusion

B. Osmosis  - special diffusion where water passes through a selectively permeable membrane from an area of High concentration to an area of Low concentration  Osmosis Osmosis  Osmosis II Osmosis II Osmosis II

C. Facilitated Diffusion  - special diffusion that is made faster by using Passive Channels (leakage channels)  - can result in a conformational change in the shape of the protein.  Facilitative Diffusion Facilitative Diffusion Facilitative Diffusion  Facilitated Diffusion II Facilitated Diffusion II Facilitated Diffusion II  Facilitated Diffusion III Facilitated Diffusion III Facilitated Diffusion III

Environments that Cells might find themselves in:  A) Hypotonic Solutions – greater concentration of water OUTSIDE the cell  B) Hypertonic Solutions – greater concentration of water INSIDE the cell  C) Isotonic Solutions – even concentrations of water inside and outside the cell

How will cells react in each??  Animal cells  Hypotonic Solution  - water moves into the cell (osmosis), the cell swells, and may burst (Cytolysis)  Hypotonic Solution Hypotonic Solution Hypotonic Solution

How will cells react in each?  Animal cells  Hypertonic – water moves from inside out and the cell shrivels and dehydrates  Hypertonic Hypertonic

How will cells react in each?  Animal cells  Isotonic – water moves in and out of the cell at the same rate (Random movement)  Isotonic Isotonic

Try these:  1. The plasma membrane consists of ___ layers.  2. The molecules that make up the plasma membrane are called ______  3. The phosphate heads like water and are called ______.  4. The lipid tails don’t like water and are called ______.  5. Special protein molecules called _____ are found throughout the plasma membrane.  6. Cell markers called _______ are attached to the top of these protein molecules.  7. The Particle Theory states that all matter is made up of tiny particles and that they are in _________.  8. Cells need to move materials in and out to maintain a state of balance between what is inside and outside. This balance is called _______

 9. Cells move materials in and out in 2 ways. ___________ and ___________  10. ________transport doesn’t require the cell to expend any energy.  11. ________ transport requires the cell to use some of it’s own energy stored in _____  12. There are 3 types of Passive Transport ________, _________ and __________.  13. Movement of any particles from H to L is called ________.  14. Movement of water molecules from H to L is called ________.  15. Diffusion of particles that are helped by carrier protein is called __________.

Review of Passive Transport  Passive Transport Passive Transport Passive Transport

Another look:  Solutions

What about plant cells?  Hypotonic – water moves in and Turgor Pressure in the cell increases.

What about plant cells?  Hypertonic – water moves out of the cell and turgor pressure drops  - the plasma membrane pulls away from the cell wall and the cell wilts.  Plasmolysis

What about plant cells?  Isotonic – water moves in and out at the same rate.

Another look:

Cellular Traffic  Active Transport (uses ATP)  A) Endocytosis  B) Exocytosis  C) Movement against the “concentration gradient”.

Cellular Traffic  A) Endocytosis – movement of large particles into a cell packaged in vesicles. The cell uses energy stored in ATP  i) Phagocytosis -  - cell engulfs a large food particle by wrapping it’s cytoplasmic arms around the particle  Phagocytosis Phagocytosis

Cellular Traffic  i) Pinocytosis – cell engulfs a smaller particle or water droplet into the cell by indenting the plasma membrane. The cell uses energy stored in ATP  Pinocytosis Pinocytosis  Pinocytosis 2 Pinocytosis 2 Pinocytosis 2

Cellular Traffic  B) Exocytosis – excreting materials from a cell packaged in vesicles. The cell uses energy stored in ATP.  Exocytosis Exocytosis  Exocytosis 2 Exocytosis 2 Exocytosis 2

Cellular Traffic  C) Movement against the Concentration Gradient (L to H)  Particles are drawn against the concentration gradient using active channels that open and close using cellular energy  L to H L to H L to H  L-H L-H

Cellular Transport Review  Thirst Reflex Thirst Reflex Thirst Reflex  Passive Transport Passive Transport Passive Transport  Environments Environments  Drag and Drop Cell membrane Drag and Drop Cell membrane Drag and Drop Cell membrane

Homeostasis  All these examples of cellular traffic are designed to help the cell maintain a state of balance between the inside and the outside of the cell.