PLASMA MEMBRANE
Plasma Membrane•   Boundary that separates the living cell from    it’s non-living surroundings.•   Phospholipid bilayer• ...
Plasma Membrane - cont.• Controls traffic into and out of the cell with  phospholipids and transport proteins.• Selectivel...
Selective Permeability• The property of biological membranes  which allows some substances to cross more  easily than othe...
Fluid Mosaic• 1972 - Singer and Nicolson called the  membrane a “Fluid Mosaic Model”.• Mosaic: different proteins embedded...
Fluid Mosaic - cont.• Components of a phospholipid bilayer. 1.   phospholipids 2.   proteins - enzymes, receptors, transpo...
Transport Proteins• Transports molecules or ions across  biological membranes• 3 types of transport proteins:             ...
Uniport Transport Protein• Carries a single solute across the membrane.extracellular                   intracellularfluid ...
Symport Transport Protein• Translocate 2 different solutes simultaneously  in same direction.   extracellular             ...
Antiport Transport Protein• Exchanges 2 solutes by transporting them in  opposite directions.           directions extrace...
Diffusion• The net movement of a substance (molecules)  down a concentration gradient from an area of  high concentration ...
Osmosis• The movement of water across selectively  permeable membranes.            membranes• The water moves from a high ...
Question:    What’s in a Solution?Answer:• solute +    solvent →   solution• NaCl    +   H20    →    saltwater
Hypertonic• A solution with a greater solute  concentration compared to another solution.                                 ...
Hypotonic• A solution with a lower solute concentration  compared to another solution.                       solution     ...
Isotonic• A solution with an equal solute concentration  compared to another solution.                       solution     ...
Movement of H2O• Water will “ALWAYS” diffuses down a  concentration gradient from a HYPOTONIC  solution to a HYPERTONIC so...
Animal Cells• Animal cells placed into a hypotonic solution  will HEMOLYSIS (EXPLODE).• Animal cells placed into a hyperto...
Plant Cells• Firmness or tension (vacuole full) that is found  in plant cells (cell wall) that are in a hypotonic  environ...
Plant Cells• When the plasma membrane pulls away from  the cell wall (vacuole empty) in a hypertonic  environment (loss of...
Active Transport• The movement of molecules (small or large)  across the plasma membrane in which energy  (ATP) is require...
Sodium-Potassium Pump• The mechanism that uses energy (active transport)  released from splitting ATP to transport Sodium ...
Question:• How are large molecules transported into  and out of the plasma membranes?
Answer:• Exocytosis and Endocytosis
Exocytosis• Cell secretes macromolecules (proteins and  other biochemicals) out of cell.• Part of the Endomembrane System:...
Endocytosis• The energy requiring movement of particles  (foreign or natural) into the cell.• 3 types of endocytosis:  A. ...
A. Phagocytosis• Cell eating: cells engulf particles with  pseudopodia and pinches off a food  vacuole.                   ...
B. Pinocytosis• Cell drinking: droplets of extracellular fluid  are absorbed into the cell by small vesicles.             ...
C. Receptor-Mediated Endocytosis• Importing specific macromolecules (hormones)  into the cell by the inward budding of ves...
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Membrane

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Membrane

  1. 1. PLASMA MEMBRANE
  2. 2. Plasma Membrane• Boundary that separates the living cell from it’s non-living surroundings.• Phospholipid bilayer• Amphipathic - having both: hydrophilic heads hydrophobic tails Phospholipid• ~8 nm thick
  3. 3. Plasma Membrane - cont.• Controls traffic into and out of the cell with phospholipids and transport proteins.• Selectively permeable Transport protein
  4. 4. Selective Permeability• The property of biological membranes which allows some substances to cross more easily than others.
  5. 5. Fluid Mosaic• 1972 - Singer and Nicolson called the membrane a “Fluid Mosaic Model”.• Mosaic: different proteins embedded in the phospholipids.• Fluid: proteins and phospholipids can move freely in the membrane.
  6. 6. Fluid Mosaic - cont.• Components of a phospholipid bilayer. 1. phospholipids 2. proteins - enzymes, receptors, transport. 3. glycolipids 4. glycoproteins 5. carbohydrates 6. cholesterol
  7. 7. Transport Proteins• Transports molecules or ions across biological membranes• 3 types of transport proteins: proteins 1. uniport 2. symport 3. antiport
  8. 8. Uniport Transport Protein• Carries a single solute across the membrane.extracellular intracellularfluid fluid
  9. 9. Symport Transport Protein• Translocate 2 different solutes simultaneously in same direction. extracellular intracellular fluid fluid
  10. 10. Antiport Transport Protein• Exchanges 2 solutes by transporting them in opposite directions. directions extracellular intracellular fluid fluid
  11. 11. Diffusion• The net movement of a substance (molecules) down a concentration gradient from an area of high concentration to an area of low concentration. concentration• passive transport: NO energy is expended.• facilitated diffusion: type of passive transport which uses transport proteins.
  12. 12. Osmosis• The movement of water across selectively permeable membranes. membranes• The water moves from a high concentration to low concentration. concentration
  13. 13. Question: What’s in a Solution?Answer:• solute + solvent → solution• NaCl + H20 → saltwater
  14. 14. Hypertonic• A solution with a greater solute concentration compared to another solution. solution 3% NaCl solution 97% H2O 5% NaCl 95% H2O Red Blood Cell
  15. 15. Hypotonic• A solution with a lower solute concentration compared to another solution. solution 3% Na solution 97% H2O 1% Na 99% H2O Red Blood Cell
  16. 16. Isotonic• A solution with an equal solute concentration compared to another solution. solution 3% Na solution 97% H2O 3% Na 97% H2O Red Blood Cell
  17. 17. Movement of H2O• Water will “ALWAYS” diffuses down a concentration gradient from a HYPOTONIC solution to a HYPERTONIC solution. solution“ALWAYS REMEMBER”• HYPOTONIC → HYPERTONIC
  18. 18. Animal Cells• Animal cells placed into a hypotonic solution will HEMOLYSIS (EXPLODE).• Animal cells placed into a hypertonic solution will CRENATE (SHRIVEL). Hemolysis Crenation Red Blood Cells
  19. 19. Plant Cells• Firmness or tension (vacuole full) that is found in plant cells (cell wall) that are in a hypotonic environment is called TURGID.• This process is called TURGOR PRESSURE. Water Water Central Vacuole Cell Wall Water
  20. 20. Plant Cells• When the plasma membrane pulls away from the cell wall (vacuole empty) in a hypertonic environment (loss of water) is called PLASMOLYSIS. PLASMOLYSIS Water Water plasma membrane Cell Wall Water
  21. 21. Active Transport• The movement of molecules (small or large) across the plasma membrane in which energy (ATP) is required. required• Examples:1. Sodium (Na) - Potassium (K) Pump2. Exocytosis3. Endocytosis
  22. 22. Sodium-Potassium Pump• The mechanism that uses energy (active transport) released from splitting ATP to transport Sodium (Na+) out of and Potassium (K+) into cells. extracellular intracellular fluid fluid K+ K+ Na+ Na+
  23. 23. Question:• How are large molecules transported into and out of the plasma membranes?
  24. 24. Answer:• Exocytosis and Endocytosis
  25. 25. Exocytosis• Cell secretes macromolecules (proteins and other biochemicals) out of cell.• Part of the Endomembrane System: the fusion of transport vesicles with plasma membrane.
  26. 26. Endocytosis• The energy requiring movement of particles (foreign or natural) into the cell.• 3 types of endocytosis: A. Phagocytosis B. Pinocytosis C. Receptor-mediated endocytosis
  27. 27. A. Phagocytosis• Cell eating: cells engulf particles with pseudopodia and pinches off a food vacuole. Bacteria• Two examples: 1. White Blood Cell 2. Amoeba Food Vacuole White Blood Cell
  28. 28. B. Pinocytosis• Cell drinking: droplets of extracellular fluid are absorbed into the cell by small vesicles. vesicles• Example: 1. Fungi Food Particles Hyphae
  29. 29. C. Receptor-Mediated Endocytosis• Importing specific macromolecules (hormones) into the cell by the inward budding of vesicles formed from coated pits (receptors). Liver Cell Hormones Receptors

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