The Cell in Its Environment

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The Cell in Its Environment

• Mrs. Brunner
• Chapter 1 4
• 7th Grade

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• I. The Cell in Its Environment
• A. Cell Membrane Gatekeeper
• 1. Selective Permeability
• 2. what does the cell want to let in?
• 3. 3 ways materials move into and out of cells
• a.
• b.
• c.
• B. Diffusion Molecules in Motion
• 1. process by which molecules move from areas
• 2. main method
• 3. Remember the demonstrations?
• 4. when molecules move they bump into each other
• 5. over time
• C. Osmosis Diffusion of Water

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• C. Osmosis
• a. diffusion of water
• b. important because all chemical reactions take
  place in water
• c. if too much water moves into the cells
• d. if too much water moves out of the cell
• D. Active Transport
• a. materials move into the cell
  (diffusion/osmosis) without using energy this
  is passive transport
• b. materials that move from inside the cell to
  the outside of the cell takes energy this is
  active transport
• c. in other wordsactive transport takes
  materials from areas of less concentration to
  areas of greater concentration

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• d. main difference
• e. 2 types of active transport
• 1. transport proteins proteins in cell
  membrane that actually pick up substances
  and carry them
• 2. engulfing cell surrounds a material, absorbs
  and forms a vacuole around the substance

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• E. Why are cells so small?
• a. materials inside cell travel on a stream of
  cytoplasm
• b. if the cell was too big, the materials would
  have too far to travel and cell would probably die