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6.3 Transport
6.3 Transport:
Predict the results
What do you predict will happen if food coloring is
dropped into a beaker of water?
• Where are the molecules most
concentrated to start?
• Where are the molecules less
concentrated to?
• What is Diffusion?
•The movement of molecules from a
high concentration to a low
concentration.
6.3 Transport
KEY CONCEPT Materials move across membranes
because of concentration differences.
What is a concentration gradient?
Molecules move down a concentration gradient.
Think of a slide.
•Would energy be required?
How is Diffusion Important for cells or
your Body?
For Cellular Transport
Medications, digestion, oxygen, carbon dioxide.
6.3 Passive Transport
Passive transport :
• Molecules can move across the cell membrane
through passive transport.
• Does not require energy input from a cell.
• There are three types of
passive transport.
• Simple diffusion
• Osmosis
• Facilitated diffusion
6.3 Osmosis
Diffusion and osmosis are types of passive
transport.
• Osmosis is the diffusion of water molecules across a
semipermeable membrane.
6.3 Osmosis Solutions
Diffusion and osmosis are types of passive transport.
• There are three types of solutions.
• isotonic
•
hypertonic
•
hypotonic
Facilitated Diffusion
Some molecules can only diffuse through transport
proteins.
• Some molecules cannot easily diffuse across the cell
membrane.
• Facilitated diffusion is
diffusion through transport
proteins.
Facilitated diffusion:
 Diffusion of larger
molecules through the
protein channels in
the cell membrane.
 Passive transport- no
energy needed.
 Molecules move from
____ conc. to ____
conc.
 Examples include:
glucose, water, ions.
Active Transport:
 Movement of molecules
from______ conc. to
______ conc.
 Requires energy (ATP)
 Needs transport proteins
 Examples- Na/K pump,
endocytosis, exocytosis.
Transport of Large Molecules:
 Vesicles used small membrane sacs; move
products into, out, or within a
cell.
 Exocytosis- Materials leave a
cell.
 vesicle containing the protein
fuses with the plasma
membrane and spills its
contents outside the cell.
 Example- release of insulin
 Endocytosis-Takes material
into the cell.
 vesicles bud inward from the
plasma membrane
 Examples- phagocytosis
(solids)