Chapters 5

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Chapters 5

• Diffusion

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Diffusion into what!!!

• Plasma Membrane
• Controls what goes in and out of a cell
• Selectively Permeable
• Only certain molecules can enter or exit
• (VIP Status)
• Where are they trying to stay???
• Who has VIP???
• Whos in charge of this VIP???
• How do they roll???
• Stretch Navigator Limo)
• What hood we in???

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• Where are they trying to stay???
• CELL MEMBRANE STRUCTURE
• 1. Bilayer (means 2 layers) of phospholipids
  with proteins embedded (means inside like myspace
  slideshow comments)
• PHOSPHOLIPIDS 2 Fatty Acids (Tails) with a
• Glycerol (Head)
• Heads are Water Soluble
• Hydrophilic (Water Lovers!)
• Tails are Water Insoluble
• Hydrophobic (Water haters!)

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• More Unsaturated Fatty Acids in a Membrane, the
  more fluid it is.
• Example An amusement park
• The Wide Open Gates are like Unsaturated
  membranes
• The turn style gates that you have to walk
  through individually are like Saturated membranes.

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• Whos in charge of this VIP??? PROTEINS!!!
• 2. PROTEINS!
• TYPE 1
• INTEGRAL (Carrier) Go all the way through the
  membrane (like a host or security guard)
• Job decide what comes in (who has VIP) and
  takes them through the membrane (to the VIP
  room).
• TYPE 2
• PERIPHERAL PROTEINS Located half way through
  the fat layer (like the manager, waiter)
• Job marker, identification for what type of
  cell it is
• Example muscle, nerve, skin cells

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• How do they roll??? Limo)
• CELLULAR TRANSPORT
• Passive Transport
• -requires no energy to move
• substances
• 1. DIFFUSION Movement
• of particles from higher
• concentration to lower
• concentration across a
• membrane
• -Ex more people waiting in
• line outside than already inside
• Continuous Movement until
• DYNAMIC EQUILIBRIUM
• -which is equal amounts
• of a substance on either side.

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• 2 Ways to Diffuse
• Dissolve into the bilayer
• Ex after enter the door, fade into the crowd
• Pass through the pores
• Ex after enter the door, have a direct path to a
  location inside

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• 2. OSMOSIS Diffusion of Water Specifically
• Has its own entrance
• Ex the owner
• Direction determined by concentration of water
  (water) inside and outside the cell

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• What hood we in???
• 3 TYPES OF SOLUTIONS
• 1. ISOTONIC DISSOLVED SUBSTANCES AND WATER
  on both sides of the membrane
• Water Molecules still move, but not all in 1
  direction, maintain Dynamic Equilibrium
• Example popular spot, always packed!
• 2. HYPOTONIC DISSOLVED SUBS. AND WATER
  lower outside than in cell
• Water moves into the cell and Internal Pressure
  (TURGOR PRESSURE) increases
• Example place that lets everyone in

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• CONTRACTILE VACUOLES (animal only cells)-
  Collect excess water and excrete so cell does not
  burst.
• Common in Paramecium
• Example security guards or bouncers, kick out
  excess people

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• 3. HYPERTONIC DISSOLVED SUBSTANCES AND
  WATER higher outside than in the cell
• Water must leave cell - the cell shrinks!
• Example a very exclusive spot (extreme VIP!)
• Hypotonic Isotonic
  Hypertonic

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REAL LIFE EXAMPLE

• Plasmolysis
• Drop in Turgor Pressure because water is leaving
  the cell.
• Ex. Wilting of a plant that was not watered.
• When plants watered, leaves are crisp, high
  turgor pressure

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• Who has VIP???
• Lipid Bilayer keeps most substances out
• Substances too large or repelled
• Water is Polar
• Has a charge, like a magnet
• Repels other polar substances
• Who has VIP with Diffusion???
• Water, Oxygen, Nitrogen, Carbon Dioxide and a few
  other small non-polar molecules

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• Back toHow do they roll???
• FACILITATED DIFFUSION From HIGH to LOW
• uses energy due to size of substance
• 2 Types
• Use of Carrier Proteins
• molecule binds to carrier protein
• Protein takes molecule through the membrane
• Example host or security guard
• Use of Ion Channels
• Tiny channels in membrane for molecules to
  diffuse through

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Use of Carrier Proteins
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Use of Ion Channels
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• Back toHow do they Roll???
• ACTIVE TRANSPORT
• Requires Energy
• From LOW to
• HIGHERAgainst
• Concentration Gradient
• Example Sodium -
• Potassium Pump

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• Types of Active Transport
• ENDOCYTOSIS Cell surrounds the molecule,
  doesnt pass through the membrane.

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• EXOCYTOSIS Release of wastes from the Cell
  Vacuole

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Endocytosis and Exocytosis