Facilitated Diffusion

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Active Transport

• Sometimes cells must move against the
  concentration gradient-
• From areas of low concentration to areas of high
• This requires the cells energy ATP
• Done by transport proteins called pumps
• Larger molecules can also be transported across
  the membrane by
• endocytosis and exocytosis

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Active Transport Lab

• Background Information Congo red is a biological
  dye, that diffuses easily into the cell, like
  water
• This diffusion does not require energy
• You are using yeast cells, that I woke up by
  adding water and sugar- they are currently alive

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Lab Results

1. Macroscopically which sample is darker?
2. Microscopically. Which cells have absorbed the
   dye?
3. Are the (not boiled) yeast cells alive?
4. Are the boiled yeast cells alive?
5. Which cells moved the dye via active transport?
6. Of the cells that moved the dyeDid they move the
   dye in or out?
7. If active transport was used to move the dye, out
   via what mechanism did the dye get in?

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Endocytosis

• Endocytosis taking material into the cell by
  means of infoldings, of the cell membrane.
• The pocket is called an ENDOSOME
• Large molecules, clumps of food, and even whole
  cells can be taken up in this way.
• Two examples phagocytosis and pinocytosis.

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Phagocytosis

• Phagocytosis means cell eating.
• In phagocytosis, extensions of cytoplasm surround
  a particle and package it within a food vacuole.
  The cell then engulfs it.
• Amoebas use this method of taking in food.

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PINOCYTOSIS

• Cell drinking
• cells take up liquid from the surrounding
  environment. Tiny pockets form along the cell
  membrane, fill with liquid, and pinch off to form
  vacuoles within the cell.
• Occurs continuously and in almost all cells

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EXOCYTOSIS

• Many cells also release large amounts of material
  from the cell.
• Vesicles in the cell travel to the cell membrane,
  fuse with it, and expel the contents to the ECF.

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• http//www.maxanim.com/physiology/Endocytosis20an
  d20Exocytosis/Endocytosis20and20Exocytosis.htm