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Cells & Their Environment

Cells & Their Environment. Inside & Out. THE CELL MEMBRANE IS Semi permeable or Selectively permeable Allow certain materials through but not others What can pass & What can not? PASS NO PASS (W/O help) Small Molecules Large Molecules ( WATER ) (MACRO MOLECULES) IONS.

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Cells & Their Environment

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  1. Cells & Their Environment

  2. Inside & Out • THE CELL MEMBRANE IS • Semi permeable or Selectively permeable Allow certain materials through but not others • What can pass & What can not? PASS NO PASS (W/O help) Small Molecules Large Molecules (WATER) (MACRO MOLECULES) IONS

  3. TRANSPORT ME OUTTA HERE • Two types of processes help molecules move across the membrane (Active & Passive Transport) ACTIVE PASSIVE USES ENERGYNO ENERGY

  4. PASSIVE TRANSPORT: DIFFUSION • Most common form is DIFFUSION Which is the movement of molecules from an area of high concentration to an area of low concentration (This is called movement along the concentration gradient) I’ll talk more later

  5. PASSIVE TRANSPORT : DIFFUSION • Whataffects the rate of DIFFUSION? • Temperature: Higher Temps = FASTER • Size of Molecules: Smaller Molecules = FASTER • Concentration: Higher [ ]of molecules = Faster

  6. PASSIVE TRANSPORT : DIFFUSION DIFFUSIONalways occurs down a concentration gradient • Concentration gradient = difference between the conc. of a particular molecule in one areaand the concentration in a nearby or adjacent area

  7. PASSIVE TRANSPORT : DIFFUSION • When both areas have the same amount of molecules (dispersed evenly = STATE OF EQUILIBRIUM) diffusion stops • Some molecules need a protein’s help to move across membrane this is called FACILITATED DIFFUSION

  8. PASSIVE TRANSPORTFACILITATED DIFFUSION • During this type of diffusion LARGE molecules (MACRO MOLECULES & IONS) move down conc. gradient faster • This is how GLUCOSE is transported from the blood into body cells

  9. REVIEW • What does ACTIVE TRANSPORT mean? • What does PASSIVE TRANSPORT mean? • Define STATE OF EQUILIBRIUM • What is FACILITATED DIFFUSION?

  10. OSMOSIS: WATERS WAY • What is it? The diffusion of WATERacross a semi- permeable membrane • Form of PASSIVE TRANSPORT • Happens when two sides of membrane have different concentrations ofSOLUTES

  11. OSMOSIS: WATERS WAY • Just like otherDIFFUSING moleculeswater moves from HIGH to LOW concentrations • Let me say that again:

  12. OSMOSIS: WATERS WAY WATER MOVES FROM HIGH CONCENTRATIONS TO LOW CONCENTRATIONS

  13. Solute/Solvent What’s the Dif? • Solute is what is dissolved (gatorade powder, iced tea, hot chocolate) • Solvent is what does the dissolving (usually water) • Solution is the result of mixing solutes and solvent

  14. OSMOSIS: WATERS WAY • THESE NEXT TWO THINGS ARE KEY (MEMORIZE THEM) • HIGH WATER concentration =LOW SOLUTE concentration • LOW WATER concentration is =HIGH SOLUTE concentration

  15. OSMOSIS: WATERS WAY • Water has a natural tendency to FLOW FROM LOW SOLUTE TO HIGH SOLUTE CONCENTRATIONS • Low solute = high water conc • High solute = low water conc • This has an effect on cells

  16. OSMOSIS: WATERS WAY (We are talking from the POV of solutes here) • Isotonic "ISO" means the same If the concentration of solute is equal on both sides of the cell membrane, the water will move back and forth but it won't have any result on the overall amount of water on either side.

  17. OSMOSIS: WATERS WAY • Hypotonic "HYPO" means less there are LESS SOLUTE MOLECULES OUTSIDE THE CELL, water will move into the cell. • CELL WILL GAIN WATER AND GROW LARGER. • REMEMBER WATER MOVES FROM LOW SOLUTE TO HIGH SOLUTE

  18. OSMOSIS: WATERS WAY • Hypertonic "HYPER" means more there are MORE SOLUTE MOLECULES OUTSIDE THE CELL, which causes the water to be sucked in that direction. • CELLS SHRINK • REMEMBER WATER MOVES FROM LOW SOLUTE TO HIGH SOLUTE

  19. OSMOSIS: WATERS WAY

  20. OSMOSIS: WATERS WAY • Remember water moves from high to low BUT The terms ISO, HYPO, & HYPER are talking about the SOLUTES and how water moves based on their concentrations

  21. REVIEW • What is OSMOSIS? • What is WATER’S natural tendency? • What do the terms HYPO, HYPER, & ISO mean? • What concentration are they referring to, the water or the solutes?

  22. ACTIVE TRANSPORT: MOVIN’ ON UP • Uses energy to move against the conc. gradient (moving up a gradient) • Move from areas of low to highconcentration • Similar to Facilitated Diffusion (Uses carrier proteins) • Energy comes from ATP (Adenosine Tri Phosphate)

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