Chapter 7.2 & 7.4 Cell Transport

Cell Membrane Review Essential for homeostasis Selectively permeable

Membrane Structure Flexible (fluid) due to cholesterol Made up of many parts (mosaic) Lipid bilayer

Phospholipid Main part of cell membrane Hydrophilic head Hydrophobic tails (lipid)

Two layers of phospholipids

Membrane Proteins Have specific functions: Identify cell Receive info Transport materials

Membrane Proteins (cont.) Stroke: blood clot blocks O2 flow to brain Affects Ca pump Excess Ca causes cell death

Membrane Proteins (cont.) Drugs & Brain: Over stimulate receptors http://learn.genetics.utah.edu/content/addiction/drugs/mouse.html

An Animal Cell’s Environment Water, oxygen & glucose enter the cell Water, wastes & carbon dioxide exit the cell

Chapter 7.4 Types of Transport Insane in the Membrane

Passive Transport Movement of molecules across cell membrane without energy Ex: Diffusion, Osmosis & Facilitated Diffusion

1. Diffusion Movement of solute molecules Higher to lower concentration Solutes: oxygen, salt

Diffusion

What happens to the particles over time? WHY???

Diffusion Animation http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_diffusion_works.html

2. Osmosis Movement of water (solvent) molecules Higher to lower concentration Solvents dissolve solutes

Osmosis H2O

What happens to the water level? WHY???

Osmosis Animation http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_osmosis_works.html

Homeostasis Connection Solute & solvent want to be in equal concentrations

Osmosis Solvent Solute

3. Facilitated Diffusion Diffusion using proteins in cell membrane Used for molecules that are large (Ex. Glucose)

3. Facilitated Diffusion (cont.) Molecules with a specific shape can pass through

Applying Concepts: Day 1  2 Egg Shell Lab Vinegar diffused into egg shell Shell: Base Vinegar: Acid & H2O

Applying Concepts: Day 2  3 Egg Shell Lab Water left egg by osmosis Egg white: 90% H2O Corn syrup: 25% H2O

Applying Concepts: Day 3  4 Egg Shell Lab Water entered egg by osmosis

Active Transport Process that moves molecules from lower concentration to higher concentration Helps store molecules Requires energy

Sodium-Potassium Pump Example of active transport Helps nerves and muscles function properly

Endocytosis & Exocytosis Used when things are too large to pass through the cell membrane by any other method

Endocytosis Process where cells ingest fluids, large particles, macromolecules & other cells

Examples of Endocytosis Amoeba: unicellular organisms feeds this way White blood cells: use endocytosis to engulf & destroy bacteria & viruses

Endocytosis

Exocytosis Process where cells release substances Organelles fuse with cell membrane & release contents