With your table partner answer these questions: 1. In order for a cell to survive, what substances might need to get into a cell or out of a cell? 2. What structure do things need to get past in order to get in or out of cells? 3. Would it be easier for you to get to a place by walking with the wind or against the wind? Up hill or down hill?
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With your table partner answer these questions:
1. In order for a cell to survive, what substances might need to
get into a cell or out of a cell?
2. What structure do things need to get past in order to get in or
out of cells?
3. Would it be easier for you to get to a place by walking with
the wind or against the wind? Up hill or down hill?
In order to understand the transport of materials in
and out of the cell we will focus on the barrier
between a cell and its environment. Do you know
what that barrier is?
• Why yes of course, it is the cell membrane!
First let’s take a closer look at a
soap bubble, why?
Note how the surface is not static.
It swirls and moves freely.
Or consider the molecules in the
membrane sort of like a ball pit.
They can move around.
THINGS NEED TO PASS THROUGH THE
Cell Membrane The cell membrane is made up a __________________________.
Phospholipids have a head that is attracted to water
_____________________ and a tail that repels water ___________.
DOUBLE LIPID LAYER
HYDROPHILIC HYDROPHOBIC
In the cell, there are 2 layers of phospholipids. As you can see
in the drawing below, the 2 layers of lipids have the “heads”
facing outward toward the water, and the “tails’ facing inward
where there is no water. This double layer of phospholipids
forms a tough yet flexible _________________. MEMBRANE
Also located within the lipid bilayer are ____________________
and ____________________ chains..
Protein channels
carbohydrates
The proteins
can act as
channels or
pumps.
They also
identify your
cells and
sometimes act
as receptor sites.
The carb
chains
identify the
cell as
belonging to
you. They
are like little
labeling
flags. If a cell enters your and has different
carbohydrate chains, the white blood
cells will attack them because they
are foreign invaders of your body.
So how does stuff move in and
out of a cell?
• In some cases it moves very easily by
following a concentration gradient.
• What the heck is that?
A situation in which particles are highly concentrated in one area
and in low concentration elsewhere.
PASSIVE TRANSPORT: Movement of small particles across a
membrane WITHOUT USING ENERGY!
DIFFUSION
Random movement
of particles from
areas of high to low
concentration
OSMOSIS
THINK “H2O-
smosis”
Movement of water
from high to low
concentration
FACILITATED
DIFFUSION
Allows larger
particles to get
through by using
protein channels
THE KEYS THINGS ABOUT PASSIVE TRANSPORT ARE
1- THEY DO NOT REQUIRE ENERGY
and
2- THE THREE TYPES ARE: diffusion, osmosis, and facilitated
diffusion.
OSMOSIS
DIFFUSION OF WATER.
What makes this type of diffusion have a special name?