Transcript Aim: How does the structure of the cell membrane

Aim: How is the cell membrane
built to do its job?
What are the functions of the cell
membrane?
3 Basic Functions:
•Acts as a
container
•Selectively
permeable
•Communication
Function #1
Acts
as a
container
Holds the contents
of the cell within
Function #2
Receptors
Has
protein shapes
on the cell membrane
to communicate
Function #3
Selectively
permeable
Allows only certain
molecules in and out
Cell Membrane Structure
Bi-layer
of lipids
Embedded
with
proteins
What are the two components of
the cell membrane?
Lipids
Proteins
Components of Cell Membrane
BI-LAYER OF
LIPIDS
Lipids (lots of
lollipops with
legs)
Proteins
Membrane Proteins:
1.Transport
Proteins:
(Channels)
2.Receptor
Proteins
STRUCTURAL
CHANNEL
PROTEIN
Receptors
RECEPTORS
•Proteins for communication
•Chemicals sent from other
cells must fit
•Lock and key concept
Why is this model called the
fluid mosaic model?
+
=
•Fluid – molecules are always moving
•Mosaic – made of many different molecules
http://home.earthlink.net/~shalpine/anim/Life/memb.htm
How do some things get
through the cell membrane?
Can the elephant get into the
house?
How is the cell membrane
different from an umbrella?
An umbrella is impermeable
It does not allow materials
through
How is a window screen similar to
the cell membrane?
Both are semipermeable.
Only certain
molecules pass.
What is the difference between
these molecules?
Some are large…
Polysaccharides – many units
Some are small…
Monosaccharide – one unit
AKA: GLUCOSE
Water (Mickey Mouse)
Predict which molecules will get
through the membrane
SELECTIVELY PERMEABLE
Why do some things get
through the cell
membrane?
Small molecules are more likely to get
through the cell membrane compared to
big molecules