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Cellular Transport. What property allows the cell membrane to maintain homeostasis?. Cell membranes are selectively permeable: they let some molecules in and keep other molecules out. Weeee!!!. high. low. This is gonna be hard work!!. high. low. Two Types of Cellular Transport.
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What property allows the cell membrane to maintain homeostasis? • Cell membranes are selectively permeable: they let some molecules in and keep other molecules out.
Weeee!!! high low This is gonna be hard work!! high low Two Types of Cellular Transport Passive Transport cell does not use energy Active Transport cell uses energy
Passive transport characterisitics • Molecules move randomly • Molecules move from an area of HIGH concentration to an area of LOW concentration. • The cell spends NO ENERGY for the particles to move
3 Types of Passive Transport • Simple Diffusion • Facilitated Diffusion • Osmosis
Simple Diffusion Animation 1) Simple Diffusion • random movement of particles from high concentration lowconcentration. • diffusion continues until equilibrium is reached. EX: gases, small particles http://bio.winona.edu/berg/Free.htm
Simple Diffusion Animation 3 Factors that affect the rate of diffusion • Size of particles (permeability) • Concentration of particles • Temperature http://bio.winona.edu/berg/Free.htm
2) Facilitated Diffusion • diffusion of larger molecules through transport proteins found in the membrane • Transport proteins can be protein carriers or channels • Transport proteins are specific – they select only certain molecules to cross the membrane EX: glucose, charged ions Facilitated diffusion(Channel Protein) Facilitated diffusion (Carrier Protein) • http://bio.winona.edu/berg/Free.htm
Facilitated Diffusion: Channel Proteins Talk to a Partner
Facilitated Diffusion: Carrier Proteins Talk to a Partner
3) Osmosis • Special case of diffusion • Diffusion of WATER through a selectively permeable membrane • Water moves from high water concentration area, to low water concentration area • Water moves freely through pores. • Solute (green) too large to move across.
Turn to a Partner • Explain 3 characteristics of passive transport & • Describe each of the 3 types of passive transport
Diffusion or Osmosis?? The student sitting next to you just came from gym class and forgot to shower
Diffusion or Osmosis?? One way to get rid of slugs in your yard is to sprinkle salt on them so they lose water and shrivel up.
Diffusion or Osmosis?? It’s the end of class, and the girl sitting in front of you just sprayed perfume so she could impress the guy in her next class
Diffusion or Osmosis?? Anthony sprays water on the veggies in the produce section to “plump them up”
Now we’ll talk about 3 situations in which osmosis occurs What type of transport is osmosis?
VOCAB SOLUTE _____________ = substance that is dissolved in a solvent to make a solution _____________ = substance in which a solute is dissolved SOLVENT http://www.makash.ac.il/h_school/hst/hstsb/chem/luach/dissolve.jpg
1) Hypotonic Solution The solution has a lower concentration of solutes and a higher concentration of water than inside the cell. (Low solute; High water) Result: Water moves from the solution, to inside the cell: Cell Swells and bursts open (cytolysis)!
Think-Pair-Share The animal cell will burst in a hypotonic solution, but the plant cell will not. What organelle prevents the plant cell from bursting when in a hypotonic solution?
VACUOLES store WATER http://www.biology4kids.com/files/cell_vacuole.html OSMOTIC (turgor) PRESSURE _____________________________ Pressure exerted by the movement of water during osmosis in plants
How Organisms Deal with Osmotic Pressure • A protist like paramecium pumps water out through a contracting vacuole • Kidneyskeep the blood isotonic by removing excesssand water. • Paramecium (protist) removing excess water video
2) Hypertonic Solution The solution has a higher concentration of solutes and a lower concentration of water than inside the cell. (High solute; Low water) shrinks Result: Water moves from inside the cell, to the solution: Cell shrinks (Plasmolysis)!
3) Isotonic Solution The concentration of solutes in the solution is equal to the concentration of solutes inside the cell. Result: Water moves equally in both directions and the cell remains same size! (Dynamic Equilibrium)
What type of solutions are these cells in? B C A http://safeshare.tv/x/JShwXBWGMyY Hypertonic Isotonic Hypotonic
Think-Pair-Share • An IV is a direct infusion of liquid substances into a vein. Why would it be dangerous to give a person an IV infusion of distilled water? • What about 90% salt solution?
Active Transport • cell uses energy • actively moves molecules to where they are needed • Movement from an area of low concentration to an area of high concentration • (Low High) • Three Types:
Active Transport Protein Pumps Endocytosis Exocytosis
Sodium Potassium Pumps (Active Transport using proteins) 1) Protein Pumps • transport proteins that require energy to do work • Example: Sodium / Potassium Pumps are important in nerve responses. Protein changes shape to move molecules: this requires energy!
Endocytosis: taking bulky material into a cell • Uses energy • Cell membrane folds around food particle pulling it into the cell • “cell eating” • forms food vacuole & digests food • This is how white blood cells eat bacteria!
Two Types 1) Phagocytosis (particles) 2) Pinocytosis (liquid)
Exocytosis: Endocytosis & Exocytosis animations forces material out of cell in bulk • membrane surrounding the material fuses with cell membrane • Cell changes shape – requires energy • This is how products, such as hormones, are released from cells
Active Transport Review • Sodium-Potassium Pump • Endocytosis & Exocytosis
Turn to a Partner • Explain 3 characteristics of active transport is & • Describe each of the 3 types of active transport
Which of the following is NOT a type of passive transport? A. diffusionB. osmosisC. endocytosisD. facilitated diffusion
The movement of chloride ions from an area where chloride is concentrated to an area where chloride is less concentrated is which of these? a. diffusionb. active transportc. osmosisd. exocytosis
In an isotonic solution there would be: a. no net movement of waterb. net movement of water into the cellc. net movement of water out of the celld. bursting of the cell
When a cell bursts due to osmosis, it is in a solution that is: a. hypertonicb. isotonicc. hypotonicd. either A or C
solution 3% NaCl 5% NaCl 97% H2O 95% H2O Red Blood Cell Which way will the water move?