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Movement across the membrane

Movement across the membrane. Movement across the membranes. Cell membrane Semipermeable - some substances can pass through easily and others get blocked. Small noncharged lipids pass freely Large moleculs cannot pass Ions and charged molecules have a hard time passing.

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Movement across the membrane

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  1. Movement across the membrane

  2. Movement across the membranes • Cell membrane • Semipermeable- some substances can pass through easily and others get blocked. • Small noncharged lipids pass freely • Large moleculs cannot pass • Ions and charged molecules have a hard time passing.

  3. Movement across the membranes Semipermeable membrane

  4. Movement across the membranes • Passive transport- movement of molecules or ions without an input of energy • Molecules or ions move down their concentration gradient. They move from an area of high concentration to low concentration. This may be diffusion, osmosis or facilitated transport.

  5. Movement across the membranes • Diffusion- molecules move from areas of high concentration to low concentration. Molecules want to spread out- fewer collisions. • Solutions are made up of a solvent (liquid) and a solute (solid- can be molecule or ion)

  6. Movement across the membranes What moves across the membrane easily? Movement across the membrane

  7. Movement across the membranes • Osmosis- specific to the movement of water. We will be looking at the movement of water across the plasma membrane. Movement of water is similar to solutes in diffusion- water moves from areas of higher concentration to lower concentration.

  8. Movement across the membranes OsmosisContinued • Osmotic pressure is the pressure created by different concentrations of water on either side of a membrane. If the membrane is permeable to water, it will move down it’s concentration gradient.

  9. Movement across the membranes • Tonicity -strength of a solution in regards to it’s surrounding (example a cell placed in the following solutions) • Isotonic solution- concentration on either side of a membrane is equal. The cell is happy

  10. Movement across the membranes • Hypotonic solution- concentration on one side of the membrane has fewer solutes (more water) and water rushes into the cell. Cells burst. • Hypertonic solution- concentration on one side of the membrane has more solutes (less water) and water leaves the cell. Cells shrink and shrivel(creanation)

  11. Movement across the membranes Review of osmosis

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