Download Cell Transport Foldable Powerpoint

Membrane Transport
1) Passive Transport
• Moves from high to low concentration
• Does not require energy
3) Diffusion
• Movement of small & polar/nonpolar
particles across bilayer.
• Bilayer is permeable to the particle
O2
CO2
Glycerol
No transport proteins
are required
Rates of Diffusion depends on
1. Concentration difference
2. Temperature
3. Pressure
RATES OF DIFFUSION DEPEND ON...
concentration of the diffusing molecule
The greater the difference in concentration between two areas, the
greater the rate of diffusion ∴ direct relationship
temperature
The greater the temperature, the greater the rate of diffusion because
temperature increases the rate of molecular movement ∴ direct
relationship
pressure
The greater the pressure, the greater the rate of diffusion because
pressure increases the rate of molecular movement ∴ direct
relationship
Example:
Diffusion of CO2 and O2 into and out of lung alveoli
Watch this 1:34 minute video
Add red dots to illustrated the
movement of oxygen gas.
Add blue dots to illustrated the
movement of carbon dioxide gas.
Be sure to correctly show movement
from areas of higher to lower
concentration!
Example:
Diffusion of CO2 and O2 into and out of eye cornea cells
The cornea is the transparent front part of the eye that covers
the iris and pupil. Because the cornea must be transparent
(so light can pass through), the cornea does not have blood
vessels. But, the cells of the cornea are alive and must
receive oxygen and get rid of carbon dioxide waste.
How can this happen? You guessed it… the cornea receives
nutrients via diffusion from the tear fluid through the outside
surface and the vitreous humour (eyeball juice) through the
inside surface.
Think about the implications for people who wear contact lenses…
If you can handle it, watch this video of a cornea transplant
4) Osmosis
• Movement of water from low solute
to high solute concentrations across
a membrane
H2O
Solutions:
Hypertonic – high solute
concentration
Hypotonic – low solute
concentration
Isotonic – equal
(equilibrium)
HYPOTONIC
The cell has a higher solute
concentration than the solution. So,
the solution is HYPOTONIC and the
cell is hypertonic. Since water moves
from hypotonic to hypertonic solutions
NET water movement will be into the cell
and the cell will swell. If too much water
moves into the cell, it will burst.
ISOTONIC
The cell has the same solute
concentration as the solution. So, the
cell and the solution are ISOTONIC.
There will be no NET water movement
and the cell will remain the same size.
HYPERTONIC
The cell has a lower solute
concentration than the solution. So,
the solution is HYPERTONIC and the
cell is hypotonic. Since water moves
from hypotonic to hypertonic solutions
NET water movement will be out of the
cell and the cell will shrink. If too much
water leaves the cell, it will die.
Be prepared to explain one of the following:
1. Why organs must be stored in an isotonic solution when
being transported for transplant surgery.
2. Why IV lines given at hospitals must be an isotonic solution
to the blood.
3. Why a person needs to use a contact lens solution and not
just water when storing and cleaning contact lenses.
4. Why salt put on roads during winter storms will kill the plants
along the roadway.
5. Why salting a slug is probably the most unethical way for a
slug to die.
6. Why your fingers will prune (swell) after a bath or swim.
5) Facilitated Diffusion
• Movement of large/charged
particles through proteins
Glucose, Amino Acids, H+
* Diameter and chemical
properties of proteins are
particle specific
PHOSPHOLIPID BILAYER MUST BE...
studded with channel proteins to
allow facilitated diffusion to occur.
Channels are holes through a protein
with very narrow diameter. The
diameter and chemical properties of
the proteins ensure that only one
type of particle can pass through.
For example, sodium ions or
potassium ions, but not both.
Example channel
created by a hole
surrounded by protein
EXAMPLE
The CFTR Channel moves
chloride ions out of the cell.
People with cystic fibrosis
have a mutation that causes
the CFTR channel to have
the wrong shape and as a
result the channel can not
move the chloride ions. The
ions build up in the cell. The
consequences are huge.
Brain Break
2) Active Transport
• Movement of particles against
concentration gradient (CG)
• Requires energy
6) Molecular Active Transport
• Uses ATP for energy to transport
substances against CG with
transport protein.
8) Primary Active Transport
• Moves from low to high
concentration
• protein pump phosphorylated by
ATP
Energy from ATP
changes protein shape
to allow molecule to
pass through
Na-K Pump
9) Secondary Active Transport
• Moves from low to high concentration
• Energy comes from primary active
transport.
Moves in 1 direction
Moves in opposite directions
EXAMPLE:
Sodium Potassium Pump in Neurons
This graphic illustrates one sodium-potassium pump over time.
On your notes, annotate with:
1. direction of sodium transport (into or out of cell)
2. direction of potassium transport (into or out of cell)
3. is sodium moving with or against its concentration gradient?
4. is potassium moving with or against its concentration gradient?
Why does this pump matter?
Long story short… without it
you’d be dead. Here’s why.
EXAMPLE:
Proton Pump
in Cellular Respiration and Photosynthesis
In order for cells to perform photosynthesis and/or
respiration, protons (also known as H+ ions) must be
pumped across the inner membranes of the
mitochondria or chloroplast.
Bonus review
opportunity! Can you
remember why
mitochondria and
chloroplasts have both
an inner and outer
membrane?
7) Bulk Transport
• Movement of large quantities of
substances with vesicles
10) Exocytosis
Removing intracellular contents by fusion
of vesicles with cell membrane
11) Endocytosis
Engulfing extracellular contents with cell
membrane creating vesicles around the
particles
14) Receptor Mediated Endocytosis
Cell engulfs target substances (ligands)
from extracellular environment
• Nutrients
Ligand
12) Phagocytosis
• Engulfs large solid content
• “Cell eating”
Bacteria
Pseudopodium
White blood cell
Phagosome (if food
particle)
13) Pinocytosis
• Engulfs liquid environment
• “Cell drinking”
• Nutrients