cell membrane - Manhasset Schools

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Transcript cell membrane - Manhasset Schools

Date: November 18, 2015
Aim #27: How does the structure of the cell
membrane contribute to its function?
Do Now: Warm-Up Notebook
Date
Title of Activity
11/19
Ribosomes and ER
Page #
48
HW:
1) Quiz next Tuesday 11/24 and Wednesday 11/25
2) “Song of the Cell” due Friday
3) Cell Organelle Worksheet
Aim #27: How does the structure of the
cell membrane contribute to its
function?
1) What is the function of the structure
below?
CELL MEMBRANE
Its function is to
CONTROL what enters
and exits the cell. It also
provides protection and
support.
2) What is the cell membrane made up of?
•Phospholipids
•Proteins
3) What is a phospholipid?
• The cell membrane is composed of a special type of
lipid (fat) called a phospholipid.
This part of the
phospholipid is
afraid of water
and tries to
avoid it.
PHOSPHOLIPID
BI-LAYER
phospholipids
4) What are types of proteins in the cell
membrane?
Membrane Proteins:
1. Structural Proteins:
2. Transport Proteins:
(Channels)
3. Receptor Proteins
4. Enzymes
STRUCTURAL
PROTEIN
CHANNEL
5) What are 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. Carbohydrate chains
attached to the surface are
important for cell-to-cell
recognition.
Receptors on cell membrane are involved in cell
communication
Cell receptor
(receptor
molecule)
Signal 1 is released from
cell B and sent to cell A
Signal 2 is released by
cell A and sent to cell B
6) 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.
http://home.earthlink.net/~shalpine/anim/Life/memb.htm
Fluid Mosaic Model…
How is the cell membrane
different from an umbrella?
An umbrella is impermeable
It does not allow materials through
7) 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
permeable-it
allows materials
through
8) Do all things get through the cell
membrane?
NO!
The cell membrane is SELECTIVELY PERMEABLE
because it allows certain substances through and
prevents other substances from passing.
What is the difference between
these molecules?
Can the elephant get into the house?
Why do some things get
through the cell membrane?
Small molecules are more likely to get through the
cell membrane compared to big molecules
10) What will get through the
cell membrane?
• Water
• Glucose
• CO2
• O2
• And other small
molecules
Protein
lipid
Lipid:
hydrophobic
tail
Lipid: hydrophilic head
Big Cell Membrane Foldable
Activity
1. Phospholipid
• Main component of cell membranes
• Each phospholipid contains a polar
head that is made up of phosphate
and choline and it contains two
nonpolar fatty acid tails.
• All the non-polar tails turn towards
one another in an attempt to exclude
as much water (which is a polar
molecule) as possible.
2) Phospholipid bilayer
• Two layers of phospholipids that
are arranged so that each layer
has its hydrophobic fatty acid tails
facing each other to create a
hydrophobic core.
• Selectively permeable
3) Integral Protein
• Have at least one region embedded
within the hydrophobic core of the
bilayer.
• Transmembrane proteins are the
most typical type of integral
proteins. They span the entire
bilayer.
4) Peripheral Protein
• Proteins that lie on and are secured
to the inner or outer surface of the
cell membrane.
• Do not interact with the
hydrophobic core of the bilayer.
5) Cholesterol
• Provide the membrane with the
proper amount of fluidity and
stability.
• Plant and bacterial cells do not
contain cholesterol in their cell
membranes.
6) Glycolipid
• Phospholipid contains a sugar chain
on its surface.
• Function as markers for cell
recognition.
7) Oligosaccharide (Sugar Chain)
• Short chain or branched chain of sugars
that are attached to certain proteins
and phospholipids on the membrane.
This modification of the membrane
only exists on the outside surface.
8) Glycoprotein
• Protein that contains a sugar chain
on its surface.
• Serve many different functions
from structural components to
receptors to enzymes.
9) Transport
• Transport proteins are used to help
substances that cannot cross the
lipid bilayer move across the
membrane. These substances
cannot cross because they are
charged (ions) or too large (glucose)
or both (amino acids). Transport
proteins are used for facilitated
transport and active transport.
10) Attachment and Recognition
• Proteins that are exposed on the
intracellular and extracellular
side of the membrane can have
attachment sites for different
elements on either side of the
membrane.
11) Receptor for signaling
• These proteins are receptors
that can bind to hormones.
When bound they can trigger
a signal that begins a cascade
of reactions within the cell.
12) Enzymatic Activities
• Involved in catalyzing
biochemical reactions