Download Notes - Diffusion and the Cell Membrane

Diffusion and the
Cell Membrane
I. Diffusion
http://www.youtube.com/watch?v=Vzwh4hSHS7s
A. Energy- all particles are moving all the
time.
B. Diffusion – particles spread out from
areas of high concentration to areas of
lower concentration until spread evenly.
C. Dynamic Equilibrium – eventually,
particles are evenly spread (but still
moving)
Why do smells go away?
Do oil and water mix?
Why or why not?
II. Phospholipids – Make up the
_________ ________ (or the Cell
membrane)
III. Lipid Bilayer around a Cell
IV. Diffusion and the Cell Membrane
• How do O2, H2O, and Sugar get into a
cell?
• How do cells recognize foreign invaders?
A.
Passive Transport
Simple Diffusion
1. _______________
______________ smaller particles like _____________
Oxygen (O2)
can simply slide into a cell through the
phospholipids
lipid bilayer
_______________
of the __________
from a ______________
to a
higher
______________
lower
concentration.
Facilitated ______________
Diffusion
2. _______________
- larger
particles like ______________
can diffuse from
sugar
a ________________
to a _______________
higher
lower
concentration, but they need doors called
____________
protein _______________.
channels
*** Since both simple diffusion and facilitated
diffusion require no ___________
energy , they are
passive
referred to as _____________
transport.
B.
Active Transport (actually,
it’s the opposite of diffusion)
• Sometimes a cell
needs to move
particles against a
concentration
gradient from a
lower
_____________
to a
______________
higher
concentration.
• For example, bone cells have
a lot of _____________
in
calcium
them. To grow and stay healthy
these cells need to _________
push from outside to inside
calcium
the cell. Since the particles
must be pushed against the
concentration
______________
_____________
from a lower
gradient
to a ____________
higher
concentration, _________
energy
must be used with special
protein channels that
pump
“__________”
the calcium ions
into a cell.
• *** Since this process requires
____________
and the movement of
energy
particles in the opposite direction of
active
diffusion, it is called _____________
transport.
Active vs. Passive Transport
V. Carbohydrate Chains
ID cards
• They are like ___
______
for the cells.
________
White
blood cells
float around your body
looking at the
carbohydrate
________________
chains of cells,
________
looking for
foreign invaders If an
______________.
invader is found, the
WBC will ___________
engulf
______
the invader and break it
apart with
its lysosomes
_______________.