DIFFUSION AND OSMOSIS

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DIFFUSION AND OSMOSIS
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3.4 Diffusion and Osmosis
KEY CONCEPT Materials move across membranes
because of concentration differences.
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Diffusion and Osmosis

• Concentration Gradient the gradual difference
  in the concentration of solutes in a solutes in a
  solution between two regions.

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3.4 Diffusion and Osmosis
Passive transport does not require energy input
from a cell.

• Molecules can move across the cell membrane
  through passive transport.

• There are two types of passive transport.

• diffusion

• osmosis

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3.4 Diffusion and Osmosis
Diffusion and osmosis are types of passive
transport.

• Molecules diffuse down a concentration gradient.

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3.4 Diffusion and Osmosis
Diffusion and osmosis are types of passive
transport.

• Osmosis is the diffusion of water molecules
  across a semipermeable membrane.

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3.4 Diffusion and Osmosis
Diffusion and osmosis are types of passive
transport.

• There are three types of solutions.

• isotonic

• hypertonic

• hypotonic

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Diffusion and Osmosis

• In terms of the solution
• Hypertonic When the solution is more
  concentrated than whats inside the cell. This
  means water moves out to try and even out the
  concentration gradient. (The cell shrinks..i.e
  your fingers in the bathtub)
• Hypotonic When the concentration is less
  concentrated than whats inside the cell the
  water moves in to try and even out the
  concentration gradient. (The cell bursts or
  lyses.)
• Isotonic When the concentration inside the cell
  is equal to that outside. No net change in water.
  
• Gizmo

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3.4 Diffusion and Osmosis
Some molecules can only diffuse through transport
proteins.

• Some molecules cannot easily diffuse across the
  cell membrane.

• Facilitated diffusion is diffusion through
  transport proteins.

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Review

• Plants Cells vs Animal Cells
• Two organelles that are in plants that are not in
  animals
• Chloroplasts- which is where photosynthesis
  occurs
• Cell Wall-Which helps make the plant rigid and
  support the change in water pressure.
• You will not see these in animal cells.

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Review

• Prokaryotic Cells Single celled organisms (i.e
  Bacteria) Have no nucleus, have no organelles.
• Eukaryotic single or multicelled organisms. Have
  nucleus, have organelles
• Golgi Apparatus- packages, prepares and
  distributes proteins.
• Nucleus- made up of the nuclear envelope and the
  nucleolus

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Lab Report

• 6 Pieces of Information
• Purpose- raises the question that you sought to
  investigate with the experiment
• Hypothesis- is a tentative explanation for an
  observation. Often written in an if/then format.

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Lab Report

• Materials-List of things needed and used (Needs
  to be as precise as possible include dependent
  and independent variable, make sure you know or
  indicate your control group)
• Procedure- Exactly what you did to test your
  hypothesis. Use action verbs , perhaps number the
  steps

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Lab Report

• Observations and Data- Anything you measured
  during the experiment. (also anything you saw,
  touched, felt, smelled or heard)
• Data Analysis/Results- Did your test support you
  hypothesis. What conclusions can you draw by
  looking at the data.