Transcript Aim: How does the structure of the cell membrane contribute to its

Aim: How does the structure of the cell
membrane contribute to its function?
Do Now: Describe the function of the
cell membrane.
HW: page 199 #29
What is the function of the
structure below?
• CONTROLS
what enters and
exits the cell.
• provides
protection and
support.
Cell membrane Structure
• Phospholipids
• Proteins
Label the diagram:
• The cell membrane is composed of a special
type of lipid (fat) called a phospholipid.
PHOSPHOLIPID
BI-LAYER
Proteins
Membrane Proteins:
1. Structural Proteins:
2. Transport Proteins:
(Channels)
3. Receptor Proteins
4. Enzymes
STRUCTURAL
PROTEIN
CHANNEL
Receptors
RECEPTORS
Receptors found on the
cell surface aid in cell to
cell communication.
Messengers (hormones)
from other cells bind to
these receptors (based
on shape) and transfer
information.
Why is this model called the fluid
mosaic model?
+
=
Fluid because the molecules are always
changing position with each other and mosaic
because it is made of different kinds of
molecules.
How is the cell membrane different
from an umbrella?
An umbrella is impermeable
It does not allow materials through
How is an umbrella different from a
window screen?
The window screen is permeable
It allows materials through
How is a window screen
similar to the cell
membrane?
The cell
membrane is
semi-permeable
-it allows certain
materials
through
What will get through the
cell membrane?
What is the difference between
these molecules?
Can the elephant get into the house?
Do all things get through the cell
membrane?
NO!!! The cell membrane is
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
What can pass through the cell
membrane?
•
•
•
•
•
•
CO2
O2
H2O
Glucose
Starch
Charged particles (Na+)