Physical Phenomena

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Physical Phenomena

• Nancy G. Morris
• Volunteer State Community College

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I. General Definitions

• INTRACELLULAR
• within a cells protoplasm
• internal activity
• INTERCELLULAR
• activities occurring between two or more cells
• EXTRACELLULAR
• outside the cell
• activities occurring outside the cells
  protoplasm

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I. General Definitions

• SOLVENT
• liquid capable of dissolving a solute
• SOLUTE
• the dissolved substance
• SOLUTION
• the mixture of solute and solvent

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I. General Definitions

• DIFFUSION
• movement of substances from where they are more
  concentrated to where they are less concentrated
• diffusion is dependent on
• 1. temperature
• 2. size of diffusing molecule
• 3. concentration
• the greater the difference in concentration
  (concentration gradient) the more rapidly
  diffusion occurs

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I. General Definitions

• DIALYSIS
• diffusion of substances through a semipermeable
  membrane
• requires a concentration gradient

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I. General Definitions

• OSMOSIS
• diffusion of water through a semipermeable
  membrane
• OSMOTIC PRESSURE
• pressure required to stop osmotic movement of
  water into a solution
• a measure of osmotic potential
• OSMOTIC POTENTIAL
• tendency for water to move across a semipermeable
  membrane into a solution
• the greater the concentration, the greater the
  osmotic pressure of the solution

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Osmosis
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I. General Definitions

• CAPILLARITY
• the adhesion of a liquid and a solid
• the attraction of a liquid to a solid surface
• ADSORPTION
• the adhesion of one substance to another

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II. The Process of Diffusion
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III. Comparisions of Solutions

• HYPERTONIC
• solution which is higher in solute concentration
  when compared to another solution
• ISOTONIC
• solution which is same in solute concentration
  when compared to another solution
• HYPOTONIC
• solution which is lower in solute concentration
  when compared to another solution

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Water balance of cells
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IV. Phenomena Created Due to Osmosis

• Turgor Pressure
• internal pressure exerted on the cell wall by
  the cells contents
• Plasmolysis
• shrinking of a cells cytoplasm due to a
  hypertonic environment
• Crenation
• plasmolysis of a red blood cell (erythrocyte)
• Hemolysis
• rupture of a red blood cell due to a hypotonic
  environment

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V. Brownian Movement

• Visible movement of particles in a solution due
  to collisions between molecules
• helps to distribute substances within a cell or
  system

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VI. How materials enter and leave cells

• PASSIVE TRANSPORT
• directional movement of substances due to
  concentration gradient
• simple dialysis
• no energy is expended

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VI. How materials enter and leave cells

• FACILITATED TRANSPORT
• passive transport aided by a carrier molecule
  such as a permease enzyme
• no energy is expended

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One model for Facilitated Transport
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VI. How materials enter and leave cells

• ACTIVE TRANSPORT
• movement of substances across the cell
  membrane against the concentration gradient
• often enzymatic
• revolving door - molecules are picked up
  outside and revolved through the membrane and
  released on the opposite side
• REQUIRES ENERGY

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Comparison of Active and Passive Transport
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8.16 A special type of Active Transport
Cotransport
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VI. How materials enter and leave cells

• ENDOCYTOSIS
• endo within
• cyto cell
• sis process
• pinocytosis
• cell drinking
• phagocytosis
• cell eating

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VI. How materials enter and leave cells

• EXOCYTOSIS
• exo external
• cyto cell
• sis process
• reverse pinocytosis
• reverse phagocytosis

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Endocytosis in animal cells
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VII. The Physical Nature of Protoplasm

• Colloid
• Sol-gel transformation