CELLULAR TRANSPORT

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CELLULAR TRANSPORT

• What gets in and what gets out?

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Passive Transport

• 1- Diffusion - occurs when there is an unequal
  concentration of molecules on one side of the
  cell compared to the other. The molecules move
  from the area of high concentration to an area of
  lower concentration until a dynamic equilibrium
  is reached.
• USED BY Small Hydrophobic Molecules O2 ,CO2, N2
• activity

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Diffusion
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Passive Transport

• 2 Osmosis - the diffusion of water through a
  selectively permeable membrane. The membrane is
  permeable to water, but impermeable to the larger
  molecules. Water diffuses from an area of high
  water concentration to an area of lower water
  concentration until the equilibrium between water
  and solute is reached.
• USED BY H2O
• demo

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Passive Transport

• 3 - Facilitated diffusion Gatekeeper proteins
  open and close paths through the cell membrane
  allowing some molecules to pass freely. It allows
  materials to move in and out of the cell much
  more quickly than regular diffusion and does not
  require energy from the cell.
• USED BY Glucose. Diffuses into red blood cells
  faster than other similar sugars.

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Active Transport

• The movement of materials from an area of lower
  concentration to an area of higher concentration
  by expending energy is called active transport.
• Carrier proteins receive energy that allows them
  to aid in active transport.

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Active Transport

• 1 Transport Carrier Proteins Proteins open
  and close paths through the cell membrane
  allowing some small solutes to pass through.
  Energy is required to transport the solutes
  against the concentration gradient.
• USED BY Sodium-potassium pump

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Animation and quiz http//highered.mheducation.com
/sites/0072495855/student_view0/chapter2/animation
__how_the_sodium_potassium_pump_works.html
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Active Transport

• 2 Endocytosis the process by which cells
  ingest materials.
• Large molecules can not pass through the cell
  membrane.
• The particle pushes against the membrane and
  forms an indentation. The cell membrane wraps
  around the particle and engulfs it into a
  vacuole.
• Often enzymes from lysosomes are then used to
  digest the molecules.

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Active Transport

• 2a Pinocytosis the process of engulfing
  dissolved molecules.
• USED BY fat droplets engulfed by cells of the
  small intestine

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Active Transport

• 2b Phagocytosis the process of engulfing
  solid particles. Can be used to engulf whole
  cells.
• USED BY invading microbes engulfed by white
  blood cells

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Active Transport

• 3 Exocytosis the process by which large
  molecules in the cell are transported to the
  external environment.
• Materials are contained in vesicles. The
  vesicles fuse with the membrane and then the
  material is released.
• USED BY waste materials released from the cell.
  Transmitter chemicals emitted from nerve cells.

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Organizer

• Make a chart to organize the following key terms
• Cellular transport
• Diffusion
• Osmosis
• Facilitated diffusion
• Active transport
• Endocytosis
• Transporters
• Passive transport
• Exocytosis

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Questions

• Why are cell membranes a bilayer?
• Why are proteins important for the functioning of
  a cell? Provide examples
• Why are cells so small?
• Compare and contrast
• Passive Active transport
• Diffusion Facilitated Diffusion
• Diffusion and Osmosis
• Why must tissues used in medical procedures be
  bathed in a solution of the same osmolarity as
  the cytoplasm?

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Reference images

• http//faculty.southwest.tn.edu/rburkett/GB1-osmos
  is.htm