1 Golgi Bodies  Stacks of flattened sacs  Have a shipping side (cis face) & a receiving side (trans face)  Receive proteins made by ER  Transport vesicles with modified proteins pinch off the ends Transport vesicle CIS TRANS

2 Golgi Bodies Look like a stack of pancakes Modify, sort, & package molecules from ER for storage OR transport out of cell

3 Golgi Animation Materials are transported from Rough ER to Golgi to the cell membrane by VESICLES

4 The Plasma Membrane The Plasma Membrane - Gateway to the Cell copyright cmassengale

5 Photograph of a Cell Membrane copyright cmassengale

6 Cell Membrane flexible The cell membrane is flexible and allows a unicellular organism to move copyright cmassengale

7 Homeostasis  Balanced internal condition of cells  Also called equilibrium  Maintained by plasma membrane controlling what enters & leaves the cell

8 Functions of Plasma Membrane Protective barrier Regulate transport in & out of cell (selectively permeable) Allow cell recognition Provide anchoring sites for filaments of cytoskeleton

9 Functions of Plasma Membrane Provide a binding site for enzymes Interlocking surfaces bind cells together (junctions) Interlocking surfaces bind cells together (junctions) Contains the cytoplasm (fluid in cell) Contains the cytoplasm (fluid in cell) copyright cmassengale

Movement across the Cell Membrane

Types of Transport 1.Simple Diffusion 2.Osmosis 3. Facilitated Diffusion 4. Active Transport

Diffusion  Move from HIGH to LOW concentration  “passive transport”  no energy needed  Move across membrane diffusionosmosis movement of water

Diffusion across cell membrane IN food carbohydrates sugars, proteins amino acids lipids salts, O 2, H 2 O OUT waste ammonia salts CO 2 H2OH2O products cell needs materials in & products or waste out IN OUT Can it be an impenetrable boundary? NO!

Diffusion through phospholipid bilayer  What molecules can get through directly?  fats & other lipids inside cell outside cell lipid salt aa H2OH2O sugar NH 3  What molecules can NOT get through directly?  polar molecules H2OH2O  ions  salts, ammonia  large molecules  starches, proteins

Osmosis is diffusion of water  Water is very important to life, so we talk about water separately  Diffusion of water from high concentration of water to low concentration of water  across a semi-permeable membrane

Channels through cell membrane  Membrane becomes semi-permeable with protein channels  specific channels allow specific material across cell membrane inside cell outside cell sugaraa H2OH2O salt NH 3

Facilitated Diffusion  Diffusion through protein channels  Move high to low.  Proteins move specific molecules across cell membrane  no energy needed “The Bouncer” open channel = fast transport facilitated = with help high low

Active Transport “The Doorman” conformational change  Cells may need to move molecules against concentration gradient (low to high)  protein “pump”  “costs” energy ENERGY low high

Getting through cell membrane  Passive Transport  Simple diffusion  Movement molecules through cell membrane  high  low concentration gradient  Osmosis  Movement water through protein  high  low concentration gradient  Facilitated transport  through a protein channel  high  low concentration gradient  Active transport  diffusion against concentration gradient  low  high  uses a protein pump  requires ATP ENERGY

Transport summary simple diffusion facilitated diffusion active transport ENERGY

Any Questions??