Cell Transport

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Cell Transport

• Biology

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Quick Review

• What part of the cell controls what enters and
  exits the cell?
• THE CELL MEMBRANE!

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The Cell Membrane

• The cell membrane is SELECTIVELY PERMEABLE.
• Lets break this phrase down
• Selective choice
• Permeable stuff can pass through it
• Selectively Permeable some substances can pass
  through the cell membrane while others cannot

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How do things move in and out?

• Substances enter/exit the cell in one of three
  ways
• Diffusion
• Osmosis
• Active Transport
• Diffusion Osmosis are
• examples of Passive Transport

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Active vs. Passive Transport

• Passive Transport
• Molecules move from high to low concentration
• Does not require energy
• Examples Diffusion, Osmosis, Facilitated
  Diffusion
• Active Transport
• Molecules move from low to high concentration
• Requires Energy

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DIFFUSION

• The movement of molecules from an area of high
  concentration to an area of low concentration

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OSMOSIS

• The diffusion of water across a selectively
  permeable membrane.

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FACILITATED DIFFUSION

• The passive transport of materials across a
  membrane with the help of proteins.

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SOLUTIONS

• HYPERTONIC concentration of water is higher
  inside the cell than outside- water leaves the
  cell.
• HYPOTONIC concentration of water is higher
  outside the cell than inside- water enters the
  cell.
• ISOTONIC concentration of water is the same
  outside the cell and inside -dynamic equilibrium

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Dynamic Equilibrium

• DYNAMIC movement
• EQUILIBRIUM a balance
• At dynamic equilibrium the molecules have reached
  a balance of movement
• There is no more high to low movement
• Molecules move equally in all directions at the
  same time

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Another Review
Diffusion will always be from an area
of ___________ concentration to an area
of ____________ concentration. It will continue
until _______________ _______________ is
reached.
HIGH
LOW
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Active Transport Proteins

• Use chemical energy from the cell to change their
  shape and allow substances to pass through the
  membrane

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ENDOCYTOSIS-2 types
Cells surround and takes in material from the
environment forming a vesicle or vacuole.

• Phagocytosis
• large particles
• Cell eating
• Pinocytosis
• Water and dissolved substances
• cell drinking

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EXOCYTOSIS

• Vacuoles fuse with the cell membrane and release
  material to the outside of a cell

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ACTIVE TRANSPORT

• From low to high concentration
• Requires energy from the cell

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PASSIVE TRANSPORT

• Molecules move from high to low concentration
• Does not require energy
• Diffusion
• Osmosis
• Facilitated diffusion