Cellular Transport How Molecules Are Transported Across The Cell Membrane.

Essential Questions How do cells maintain homeostasis? How are cell membranes (plasma membranes) selectively permeable (semi-permeable)? Why is it important that cells are able to transport molecules with (active transport) and without (passive transport) energy?

Types of Cellular Transport Passive Transport cell doesn’t use energy 1.Diffusion 2.Facilitated Diffusion 3.Osmosis Active Transport cell does use energy 1.Protein Pumps 2.Endocytosis 3.Exocytosis high low This is gonna be hard work!! high low Weeee!!! Animations of Active Transport & Passive TransportAnimations

Passive Transport Cell uses no energy Movement of particles along a concentration gradient from area of high concentration to area of low concentration. –(High  Low) Concentration gradient - difference in concentration of substance from one area to another. Three types:

3 Types of Passive Transport 1. Diffusion 2. Facilitative Diffusion 3. Osmosis

1. Diffusion Diffusion: - movement of particles from area of high concentration to an area of low concentration. –continues until molecules evenly spaced or at equilibrium (equal) –Temperature and size of molecule affect rate of diffusion Simple Diffusion AnimationSimple Diffusion Animation

Facilitated diffusion: diffusion of specific particles across membrane with help proteins channels. (High  Low concent.) a.Carrier Proteins a.Transports large particles that can’t pass through on own. Ex. Glucose b.Ion Channels Protein - transports ions (charged particles). a.Ex. Na +, K +, Cl - Facilitated diffusion (Channel Protein) Diffusion (Lipid Bilayer) : 2. Facilitated Diffusion Carrier Protein AB

High Concentration Low Concentration Cell Membrane Glucose molecules Protein channel Facilitated Diffusion Go to Section: Transport Protein Through a  Cellular Transport From a- High Low Channel Proteins animationsChannel Proteins

Osmosis: diffusion of water through a selectively permeable membrane –Moves from high concentration of water to low concentration of water Cell cannot control movement of water through cell membrane as water too small and in such abundance. –Moves through pores Osmosis Osmosis animation 3. Osmosis

Effects of Osmosis on Life Substances dissolve well in water. –Solute: what is being dissolved –Solvent: what dissolves the solute In salt water, the solute is the salt and the solvent is the water Water moves from low solute to high solute 3 kinds of water solutions that affect a cell’s homeostasis.

1. Hypotonic Solution Hypotonic: Concentration of solutes outside is lower than it is inside the cell. (Low solute; High water) Result: Water moves inside cell: Cell Swells and bursts open ( called lyse)! Osmosis Animations for isotonic, hypertonic, and hypotonic solutionsOsmosis

2. Hypertonic Solution Hypertonic: Concentration of solutes outside is higher than inside the cell. (High solute; Low water) Result: Water moves out of cell : Cell shrivels or shrinks! Osmosis Animations for isotonic, hypertonic, and hypotonic solutionsOsmosis shrinks

3. Isotonic Solution Isotonic: Concentration of solutes outside and inside cell are equal. Result: Dynamic Equilibrium- Water moves in and out equally. Cell same size! Osmosis Animations for isotonic, hypertonic, and hypotonic solutionsOsmosis

In what type of solution are these cells? A CB HypertonicIsotonicHypotonic

Real Life Examples If you are stranded in the ocean, should you drink the water to stay alive?

Why do we wrinkle when we are in the tube too long?

Why does it help to gargle salt water when we have a sore throat?

What happens to a snail when you put salt water on it?