Plasma Membrane

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Plasma Membrane

• Structure
• Function
• Activity

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Plasma Membrane

• Phospholipids
• Basic molecular component of membrane
• Must be fluid
• Membrane proteins
• Fluid Mosaic Model

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Plasma Membrane

• Phospholipid bilayer
• Formed by association of hydrophobic tails
• Polar (hydrophillic) groups form inside and
  outside of membrane

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Plasma Membrane

• Membrane Proteins
• Proteins are integral or peripheral
• Proteins involved in plasma membrane functions

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Plasma Membrane

• Fluid Mosaic Model
• Membrane must be fluid to function
• Components are free (to a degree) to move across
  surface

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Plasma Membrane

• Functions
• Boundary between inside and outside
• Recognition
• Energy (respiration and photosynthesis)
• Selective permeability of materials
• Diffusion
• Active transport
• Bulk transport

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Plasma Membrane
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Plasma Membrane

• Diffusion Processes
• Simple Diffusion movement of small uncharged
  molecules
• Osmosis special case of diffusion diffusion of
  water in response to solute concentration
• Facilitated Diffusion diffusion using a channel
  protein

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Plasma Membrane

• Diffusion the movement of molecules from area
  of high concentration to low concentration

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Plasma Membrane

• Osmosis
• Isotonic
• Solute concentration same on both sides of plasma
  membrane

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Plasma Membrane

• Hypotonic
• Hypo- below
• Solute concentration less outside cell than
  inside cell

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Plasma Membrane

• Hypertonic
• Hyper- above
• Solute concentration greater outside cell than
  inside

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Plasma Membrane

• Facilitated Diffusion
• Diffusion that occurs through use of a channel
  protein

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Plasma Membrane

• Active Transport
• Movement against energy concentration gradient
• Requires energy usually in form of ATP

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Plasma Membrane

• Bulk transport
• Eukaryotic cells only
• Endocytosis
• Pinocytosis
• Phagocytosis
• Exocytosis secretory processes