Download Cell Transport

Getting Into and Out of Cells

Regulates what enters and leaves the cell and provides
protection and support.
 Made out of a phospholipid bilayer
▪ Gives it flexibility
 Also find protein embedded in the layer
▪ Which act as tunnels or pumps that help to move
materials.
▪ Some have carbohydrates attached
▪ act like chemical ID cards
▪ Allows individual cells to identify one another
Fluid Mosaic Model
Hydrophilic
Each phospholipid is
composed chemically of
2 fatty acids, a glycerol
and a phosphate.
Hydrophobic
Passive Transport
- no cellular energy required to occur
- goes with the concentration gradient
- diffusion
- facilitated diffusion
- osmosis
 Active Transport
- requires cellular energy to occur
- goes against the concentration gradient
- Endocytosis/Exocytosis
- Sodium Potassium Pump


The concentration gradient is the distribution
of particles across space from high to low
concentration

In passive transport, molecules move with
the concentration gradient
- move from high concentration to low
concentration

Primary means of cell transport
- molecules move from high to low
concentration
- movement continues with the gradient
until
the molecules are evenly distributed
- equilibrium is achieved

Particles move with the
concentration gradient
using a transport protein
in the membrane.
- ions, sugar and amino
acids all move into and
out of cells by
facilitated diffusion

The diffusion of water
across a selectively
permeable membrane
- water moves down
the concentration
gradient.
- water moves toward
higher conc. of
dissolved
material - solute

Hypotonic environment
 Little(below) solute/lots of water
What happens when you place cells in an
environment that is hypotonic to it? Hmm
Animal Cell
Plant Cell
Hypotonic
Hypertonic
Isotonic



If concentrations of dissolved solutes are less
outside the cell than inside, then water will
move into the cell.
Cells without walls will swell and may burst
(lyse) if excess water is not removed from the
cell.
Cells with walls often benefit from the turgor
pressure that develops in hypotonic
environments.



If concentrations of dissolved solutes are
greater outside the cell, then water inside the
cell will flow outwards to attain equilibrium.
This causes the cell to shrink.
As cells lose water, they lose the ability to
function or divide.



Concentration of solute inside and outside of
the cell is equal.
Water moves in and out of the cell at equal
rate.
No change in the cell.
Plasmolyzed
Cells due to
water loss
Cell membrane
pulls away
from the cell
wall.
Cytolysis:
Cell Swelling
from uptake of
water
Normal/Isotonic
Plasmolyzed/Hypertonic
Cytolysis
This usually
takes place
when cells are
placed in a
hypotonic
solution such
as distilled
water.
Normal
In Salt
Water
plasmolyze
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