Transcript Cell Membrane - Cloudfront.net

Cell Transport
chap. 7-3
https://www.pinterest.com/pin/225039312606126463/
I. Cell Membrane
1) POLAR ends face INSIDE
& OUTSIDE cell [where
water is]
2) NONPOLAR tails face
each other inside bilayer
[to avoid water]
Outside
of cell
Carbohydrate
chains
Proteins
Cell
membrane
Inside
of cell
(cytoplasm)
Protein
channel
Lipid bilayer
http://www.bioteach.u
bc.ca/Bioindustry/Inex/
3) FUNCTION:
SELECTIVE
PERMEABILITY = allows
only certain materials to
go into & out of cell
a. Why doesn’t the cell
membrane let everything
through?
HOMEOSTASIS!
- Cells maintain a stable
environment by controlling
what enters & leaves.
II. Cellular Transport – Two Major
Types (Passive & Active Transport)
1.Passive Transport = moves
molecules across cell mem.
using NO ENERGY
Movement going with the
concentration gradient
(normal flow)
A. Types of Passive Transport
1.Diffusion – molecules
move from HIGH conc. to
LOW conc.
a. Small molecules: O2,
CO2
b. Slow process
Passive Transport Video Clip

https://www.pinterest.com/pin/225039312
606104881/
PROBLEM for
Cells?
Cell membranes
are
SELECTIVELY
PERMEABLE
2. Facilitated Diffusion –
movement of molecules
with help of a carrier
protein
a.Moves large molecules
like Glucose and
Fructose (C6H12O6)
b. Faster than diffusion
http://www.sirinet.net/~jgjohnso/homeostasis.html
3. Osmosis – diffusion of
WATER across cell
membrane
* H2O moves to area with
LESS WATER
a. Direction of Osmosis:
1) Hypotonic Solution =
H2O moves INTO cell &
CELL EXPANDS
2) Hypertonic Solution =
H2O moves OUT OF cell &
CELL SHRINKS
3) Isotonic Solution = H2O
moves INTO & OUT OF
cell & cell stays NORMAL
SIZE
* EQUILIBRIUM =
concentration of molecules
is same everywhere
* Molecules never stop
moving – even at
equilibrium
nd
2
2.
Type of Transport
 Active Transport
1.moves molecules
across cell
membrane using
ENERGY
B. Types of Active Transport
1. Transport Proteins:
in membrane- move
substances from low
to high conc.
(opposite of how it
wants to move)
2. Endocytosis = cell
surrounds & ingests
materials from
OUTSIDE to
INSIDE cell using
VESICLES
http://www.sirinet.net/~jgjohnso/homeostasis.html
a. Steps:
1) membrane folds in &
forms pocket
2) Pocket closes & pinches
off in cell vesicle
3) vesicle fuses w/
organelles to release
contents
b. Two Types of Endocytosis:
1)Phagocytosis – LARGE
particles (food) or whole
CELLS (bacteria) into
cell
2) Pinocytosis – large
amounts of liquids/
fluids into cell
3. Exocytosis –releases large
amounts of material to the
OUTSIDE of the cell using
VESICLES
a. Steps:
1)Vesicle forms, travels to
& fuses w/ cell mem.
2)Vesicle opens to
outside & releases
contents
http://www.sirinet.net/~jgjohnso/homeostasis.html

Video clip