What is Life?

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What is Life?

• Unit 4.2 The Cell Part 3

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Cell Membrane

• Hydrophilic - Water Loving
• Hydrophobic - Water Fearing

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Cell Membrane
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Cell Membrane

• Hydrophilic Heads
• Hydrophobic Tails

• Point outward attracted to water environment
  inside outside of cell
• Point inward attracted to organic cells

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Cell Membrane

• Membrane Proteins

• Gate Keepers of the Cell Membrane
• Allow certain
• molecules to
• enter leave

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Cell Membrane

• Diffusion

• Molecules move from
• HIGH Concentration
• ? LOW Concentration

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Cell Membrane

• Diffusion
• Also
• Called

• Molecules move from
• HIGH Concentration
• ? LOW Concentration
• Moving DOWN a Concentration Gradient

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Cell Membrane

• Equilibrium

• When solution has constant concentration
  throughout

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Cell Membrane

• Diffusion

• Requires NO ENERGY!
• Works best over small distances and large surface
  areas like
• Lungs
• Capillaries
• Rough ER
• etc.

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Cell Membrane

• Osmosis

• Diffusion of water from HIGH concentration to LOW
  concentration of H2O.
• OR
• From LOW concentration of solute to HIGH
  concentration of solute.

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Cell Membrane

• Transport Proteins
• Facilitated
• Diffusion

• Gate proteins that move molecules across cell
  membrane
• Lock Key mechanism
• When Transport Proteins move molecules across
  cell membrane

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Cell Membrane

• Passive
• Transport

• NO ENERGY required
• Diffusion
• Facilitated Diffusion

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Cell Membrane

• Active
• Transport

• Diffusion requiring ENERGY
• Against a Concentration Gradient

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Cell Membrane
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What is Life?

• Unit 4.2 The Cell Part 3