HOMEOSTASIS and CELL TRANSPORT

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HOMEOSTASIS and CELL TRANSPORT

• Active Transport

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Active Transport

• In many cases cells must move substances from an
  area of LOW concentration to an area of HIGH
  concentration
• This movement is against or up the concentration
  gradient
• REQUIRES the use of energy

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Active Transport

• Accomplished in two ways
• 1. Cell Membrane Pumps
• 2. Movement in Vesicles

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Cell Membrane Pumps

• Sodium-Potassium Pump
• Transports Na ions and K ions up their
  concentration gradients
• To function normally some animal cells must have
  a higher concentration of Na ions outside of the
  cell and a higher concentration of K ions inside
  the cell

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Sodium-Potassium Pump
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Sodium-Potassium Pump
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Movement In Vesicles

• Endocytosisprocess by which cells ingest
  external fluid, macromolecules and large
  particles
• Two Types
• 1. Pinocytosistransport of liquids
• 2. Phagocytosistransport of particles or whole
  cells

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Endocytosis
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Movement In Vesicles

• Exocytosissubstance is released from the cell
  through a vesicle that transports it to the cell
  surface
• Releases large molecules such as proteins,
  wastes, or toxins

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Exocytosis