Post on 20-Jan-2016
What is the cell membrane?AKA: Plasma membraneThe boundary between the cell and the
environmentDoes every cell have a cell membrane?
Yes!, Each and every cell has a cell membrane.
How do cell membranes help to maintain homeostasis?
The cell membrane allows nutrients to come into the cell
Glucose, amino acids, lipids
The cell membrane removes waste
Selective PermeabilityThe cell membrane lets some molecules in
and keeps others out
EX. A cell is low on glucose so the membrane lets in some glucose, but does not overfill the cell with the monomer.
Structure of the cell membraneWhat does the cell membrane look like up
close?
Lets look at one of these
structures up close
Structure of cell membranePhospholipids
Phosphate headGlycerol2 Fatty acid tails
Phospholipids1.) Phosphate Head
Polar Hydrophilic Make up the outer borders of the
membrane
2.) Fatty Acid Tails Nonpolar Hydrophobic Make up the inner part of the
membrane
Structure of cell membranePhospholipid bilayer
2 layers of phospholipids make up a cell membrane
Phospholipid BilayerRemember polar heads and nonpolar tails
The fluid Mosaic Model of the cell membraneLipid bilayer is not strong & firm
like a hard shell, but it is fluid like a soap bubble consistency
So, it is called the Fluid Mosaic Model (fluid like, with many proteins stuck in it)
The fluid Mosaic Model of the cell membrane
It is a flexible membrane, made fluid because of cholesterol molecules located in the phospholipid bilayer.
Proteins in the membrane move around.
Other components of the cell membraneCholesterol
Helps to stabilize the phospholipids and keep them from sticking together
Other components of the cell membraneCarbohydrates- linked to lipids or proteins
Recognition of Cells – “Name tag of cell”Ex. Is the cell a heart cell, liver cell, or brain cell?Ex. Glycolipids & Glycoproteins (marker protein)
Other components of the cell membrane
Proteins- make up 50 %- 70% of membraneRegulate which molecules enter
and which molecules leave a cell.Receive info & ID the cell
Types of proteins in the cell membraneCarrier Protein
Allow needed substances or waste materials to move through the cell membrane
Types of proteins in the cell membraneReceptor Protein
These have binding sites for molecules such as hormones or substrates to bind to that can cause a chemical rxn in the cell
Types of proteins in the cell membraneChannel or Pore protein
Hydrophilic channel – allows lipid insoluble substances to pass in and out of cell.
Types of proteins in the cell membraneGlycoproteins
Protein with what macromolecule attached to it? Carbohydrate
Functions for cell to cell recognition
Where are proteins located in the cell membrane?
Integral ProteinsProteins inside the cell membrane
Peripheral ProteinsProteins outside the cell membrane
Lets build a cell membrane togetherhttp://www.wisc-online.com/objects/
index_tj.asp?objid=AP1101 Cell membrane animation
Cell membranes help maintain homeostasis, what is that?
Cel
ls b
reat
hin...
Cel
ls g
ettin
g ...
Cel
ls m
aint
ain...
Cel
ls re
produc
...
25% 25%25%25%
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1. Cells breathing2. Cells getting blood
to them3. Cells maintaining
internal conditions4. Cells reproducing
Where would you expect to find water in this cell membrane?
Her
e H
ere
50%50%
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21 22 23 24 25 26 27 28 29 30
1. Here2. Here
When something is hydrophilic, it…
Has
a c
hemic
al...
Has
a c
hemic
al...
50%50%
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1. Has a chemical makeup that likes to be around water
2. Has a chemical makeup that does not like to be around water
This picture shows what type of protein?
Rec
epto
r Pro
te...
Chan
nel P
rote
i...
Gly
copro
tein
Car
rier P
rote
i...
25% 25%25%25%
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
1. Receptor Protein2. Channel Protein3. Glycoprotein4. Carrier Protein
Identify the structure marked on the cell membrane:
Phosp
holipid
Chole
ster
ol
Rec
epto
r pro
te...
Chan
nel p
rote
i...
Gly
copro
tein
Car
rier p
rote
i...
Nucl
eic
acid
14% 14% 14% 14%14%14%14%
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
1. Phospholipid2. Cholesterol3. Receptor protein4. Channel protein5. Glycoprotein6. Carrier protein7. Nucleic acid
Identify the structure marked on the cell membrane:
Phosp
holipid
Chole
ster
ol
Rec
epto
r pro
te...
Chan
nel p
rote
i...
Gly
copro
tein
Car
rier p
rote
i...
Nucl
eic
acid
14% 14% 14% 14%14%14%14%
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
1. Phospholipid2. Cholesterol3. Receptor protein4. Channel protein5. Glycoprotein6. Carrier protein7. Nucleic acid
Identify the structure marked on the cell membrane:
Phosp
holipid
Chole
ster
ol
Rec
epto
r pro
te...
Chan
nel p
rote
i...
Gly
copro
tein
Car
rier p
rote
i...
Nucl
eic
acid
14% 14% 14% 14%14%14%14%
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
1. Phospholipid2. Cholesterol3. Receptor protein4. Channel protein5. Glycoprotein6. Carrier protein7. Nucleic acid
Identify the structure marked on the cell membrane:
Per
ipher
al P
ro...
Inte
gral P
rote
...
50%50%
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
1. Peripheral Protein2. Integral Protein