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Bell Work

Bell Work. 1. If a membrane allows movement of only certain materials, it is called ___. Somewhat permeable Selectively permeable Somewhat impermeable Selectively permeable. Notes: Cell Membrane. Cell membranes are also called plasma membranes Facts: Selectively permeable

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Bell Work

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  1. Bell Work 1. If a membrane allows movement of only certain materials, it is called ___. Somewhat permeable Selectively permeable Somewhat impermeable Selectively permeable

  2. Notes: Cell Membrane • Cell membranes are also called plasma membranes • Facts: • Selectively permeable • Allows certain materials to move in and out of the cell when needed, but keeps other material from crossing the membrane • Made of phospholipid bilayer • Water soluble phosphate head (hydrophilic) • Water insoluble fatty acid tail (hydrophobic) • Has various carbohydrates, proteins and cholesterol mixed into the bilayer

  3. Question 1. Which of these is NOT a type of cellular transport? endocytosis exocytosis diffusion nucleocytosis

  4. Question 2. The cell membrane is made primarily of ___. carbohydrates Nucleic acids proteins phospholipids

  5. Question 3. When active transport is used, the cell ______. Does not use any of its own energy Uses some of its own energy Uses energy from other cells Uses the energy stored mainly in the nucleus

  6. Question • During passive transport, a cell ________. • Does not use any of its own energy • Uses some of its own energy • Uses energy from other cells • Uses the energy stored mainly in the nucleus

  7. Notes: Cellular Transport • Diffusion • Movement of molecules from an area of higher concentration to an area of lower concentration. • Passive Transport • It does not require energy • Oxygen and Carbon Dioxide use diffusion • Not all molecules can enter and leave by diffuison • Once equilibrium is reached they stop

  8. Notes: Cellular Transport Concentration Gradient • The name of the difference that exist when there is a difference in concentration in two areas Equilibrium • When the concentration on both sides of the cell membrane are equal

  9. Draw Concentration Gradient

  10. Notes: Facilitated Diffusion • Transport Proteins • Allow some of the ions, sugars, and amino acids to pass through from an area of high concentration to an area of low concentration • Many different types • Each selective for a specific molecule • Form of PASSIVE TRANSPORT

  11. Questions Why is diffusion a type of passive transport? • A. It moves materials across a cell membrane • B. It does not require any of the cell’s energy • C. It does not need activation by an enzyme • D. It continues until equilibrium is reached

  12. Questions During diffusion, molecules move _____. • A. from an area of higher concentration to an area of lower concentration • B. from an area of lower concentration to an area of higher concentration • C. across a cell membrane with the use of cellular energy • D. against a concentration gradient

  13. Notes: Osmosis • Osmosis • Passive transport • Moves molecules down a concentration gradient • 2 Facts • Always a movement of water molecules • Moves water molecules across a selectively permeable membrane through which the solute (dissolved particles) cannot cross

  14. Notes: Osmosis • Osmosis • Solute particles are too large to pass through the selectively permeable membrane • Like oil and water’s inability to mix, particles that are water soluble cannot pass through the middle of the membrane • To bring about equilibrium, either facilitated diffusion or osmosis must take place

  15. Notes: Isotonic Solution • Isotonic • The solution on the outside of the membrane has the same concentration as the solution on the inside of the membrane • No net movement of water molecules across the membrane

  16. Notes: Hypertonic Solution • Hypertonic • The solution outside the membrane contains less water and more solute than the solution inside the membrane • water rushes out of the cell • Cell shrivels up • Example: salt on a slug

  17. Notes: Hypotonic Solution • Hypotonic • Solution on the outside of the cell membrane has a greater concentration of molecules than the solution inside the cell • More water on the outside • Ex. Wilted vegetable (celery) • Water rushes in an the cells swell

  18. Notes: Active Transport • Active Transport • Used to move molecules against a concentration gradient • Requires Energy • 3 Types of Transport Proteins help move substances in and out of the cell • channel proteins • carrier proteins • gate proteins

  19. Notes: Transport Proteins • Often the protein has a certain shape that allows it to stick to a molecule with a matching shape • Uses chemical energy to move against the gradient

  20. Notes: Endocytosis • Endocytosis • A way of allowing particles that are too big to cross the cell member to enter • Particle is enclosed with material from the cell, then pulled into the cell • In = En • Into the cell = ENDOcytosis

  21. Notes: Exocytosis • Exocytosis • Used to get rid of large particles • Undigested food, waste products or hormones • Material is enclosed in a vesicle • Vesicle meets the cell membrane, breaks open, then fuses with the membrane • Particles are released to the outside of the cell Exit the cell = EXocytosis

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