Cell Processes

1
Cell Processes

• Passive Transport - The movement of substances
  across a cell membrane without the cell using
  energy

2
Diffusion

• the movement of molecules from an area of higher
  concentration to an area of lower concentration.
  Occurs using the kinetic energy of the molecules.
  

3

• Molecules will change direction when they hit
  other particles or if there are no particles in
  the way, they will move to less concentrated
  areas.

4
Active Transport

• Energy-requiring process that move material
  across a cell membrane against a concentration
  difference

5
Concentration gradient

• the difference in concentration of a substance
  across space

6
Equilibrium

• when the concentration of the molecules of a
  substance is the same throughout an area state
  in which no net change occurs even though there
  is random movement of molecules

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• Ability for molecule to diffuse across cell
  membrane depends on
• 1. Size of molecule
• 2. Type of molecule
• 3. Chemical nature of molecule

8
Osmosis

• The diffusion of water across a selectively
  permeable membrane water moving from an area of
  greater concentration to a lower concentration
  across a selectively permeable membrane

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http//academic.brooklyn.cuny.edu/biology/bio4fv/p
age/osmofr.htm
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Hypotonic Solution

• a solution whose solute concentration is lower
  than that inside a cell water will move into the
  cell if it is placed in a hypotonic solution

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Hypertonic Solution

• a solution whose solute concentration is higher
  than that inside a cell water will move out of
  the cell if it placed in a hypertonic solution

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Isotonic solution

• a solution whose solute concentration equals that
  inside a cell

13
How Cells Deal with Osmosis

• When in a hypotonic solution, some cells will
  pump out solutes so that water is less likely to
  move into the cell

14
Contractile vacuole

• structure in unicellular organisms that removes
  excess water by contracting requires the cell to
  use energy

15
Endocytosis

• process by which substances are taken into the
  cell.

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Phagocytosis
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Pinocytosis
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Exocytosis
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• http//www.bbc.co.uk/education/asguru/biology/01ce
  llbiology/05pathways/06passivesimple/index.shtml
• http//science.nhmccd.edu/biol/membrane/osfram1.ht
  ml
• http//science.nhmccd.edu/biol/Osotutor.html

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• http//www.biosci.ohiou.edu/introbioslab/Bios170/d
  iffusion/Diffusion.html
• http//academic.brooklyn.cuny.edu/biology/bio4fv/p
  age/phago.htm
• http//www.biology4kids.com/files/cell2_pinocytosi
  s.html
• http//academic.brooklyn.cuny.edu/biology/bio4fv/p
  age/endocytb.htm
• http//academic.brooklyn.cuny.edu/biology/bio4fv/p
  age/endocyta.htm

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• Pinocytosis
• In the process of pinocytosis the plasma membrane
  forms an invagination.
• What ever substance is found within the area of
  invagination is brought into the cell.
• In general this material will be dissolved in
  water and thus this process is also refered to as
  "cellular drinking" to indicate that liquids and
  material dissolved in liquids are ingested by the
  cell.
• This is opposed to the ingestion of large
  particulate material like bacteria or other cells
  or cell debris.

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