Download Chapter 9: movement of material in and out of cell

Movement of material in and out of cell: The basics & Passive Transport:
*How does stuff move in and out of an animal cell?
Cell membrane
-Selectively permeable
- things can go in and out of cell dependent on pore size.
- this is done to maintain homeostasis or equilibrium.
Equilibrium: Molecules are distributed evenly through out area
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*What does it mean to be concentrated(not constipated or concentration)
*What happens to a piece of cheese when you grate it?
*Does the cheese increase or decrease in concentration?
The movement from one place to another is separated by a concentration gradient
Concentration Gradient
-
a difference in concentration between two places but is gone when
equilibrium is reached
example there is a gradient present in picture a but in b equilibrium has been
reached thus not gradient
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In picture b the molecules are still in movement but they are moving at the same rate(no
net movement)
Picture A
Picture B
2 types of cellular transport
a. passive transport
b. active transport
*What dose passive mean? (Relation to energy)
- No use of energy.
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A. Passive transport
- no energy used by cell to move particles across membrane
- potential energy
-energy not in use
-stored energy
Kinetic Energy – energy in motion
1. Diffusion (example of passive transport)
a. Movement of molecule from greater to lesser concentration until
equilibrium is reached. *hint remember the air freshener in class 
b. Example of Diffusion is Osmosis – the movement of water from high to
low concentration.
B. Active Transport (3 types)
Requires the cell to do work – (2 reasons why energy is required)
A. The cell has to rid itself of excess material the just keeps flowing back into the
cell ….kinda like water in a sinking ship.
B. Some times the molecules are too large to fit through the pores of the
membrane.
3 Type of Active Transport
1. Ion transport (ions are atoms with a change- they are small)
a. A.K.A. Facilitated Diffusion
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*Substances move against the concentration gradient – low -> concentration
2. Endo-Cytosis (endocytosis)
“into Cell”
-Large molecules which are too big to go thru pores can be taken in this
way – this takes energy!
-This is how a cell eats and drinks…..
3. Exo-cytosis (exocytosis)
“out of cell”
Proteins (like insulin) are secreted from cell this is also how the cell rids itself of
waste.
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