3'2 Moving cellular materials

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3.2 Moving cellular materials
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Passive Transport

• Cells need to be able to take things in and get
  things out of the cell membrane.
• The cell membrane is selectively permeable it
  allows some things in and keeps other things out.
• There are several ways that things get through a
  cell membrane.
• Passive transport is when NO energy is used to
  move things.

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Diffusion

• The random movement of particles from high to low
  concentrations.
• Diffusion if one form of passive transport.
• Equilibrium is the point when the particles are
  spread as far apart as they can or when
  concentrations are equal.
• Diffusion is how your lung and blood stream work.

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Osmosis

• Osmosis is a special case of diffusion where
  water goes across a cell membrane, high to low.
  Still passive transport.
• In plant cells water the diffuses into the cell
  helps support the cell wall.
• If water diffuses out of a cell the plant will
  wilt.

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Facillitated Diffusion

• Another special case of diffusion.
• Passive transport that uses transport proteins to
  allow large thing throught he cell membrane.
• Proteins act as doorways that can be opened and
  shut.

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Active Transport

• Any time energy is required to move a substance.
• Active transport is an uphill process.
• Uses membrane proteins called pumps.

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Endocytosis

• Moves objects very large into the cell
• Surrounds the substance with membrane to form a
  vesicle.
• Vesicles are storage and transport structures in
  a cells cytoplasm.
• Endo in

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Exocytosis

• The exact opposite of endocytosis.
• Very large objects need to be removed from a
  cell.
• Vesicle moves the cell membrane and expells its
  contents.