1. Notes: Plasma Membrane pages 19 – 24
Fluid Mosaic Model
Plasma Membrane Anatomy
(Structure)
Function – regulates what goes in and
out of the cell and holds the cell
together.
2. Fluid Mosaic Model
Plasma Membrane Anatomy (Structure)
Structure - cell membrane is a
phospholipid bilayer.
3. Fluid Mosaic Model
Plasma Membrane Anatomy (Structure)
What does that mean?
•it is bilayer – double layered
•the layers are composed primarily of
a fat molecule (lipids) with one fatty
acid replaced by a phosphate group
•if it dissociates it is easy for it to
reform which also allows it to grow
4. Result of this anatomy of phospholipid
bilayer is:
•plasma membrane has polar heads
and nonpolar tails
http://www.ccs.k12.in.us/chsteachers/Amayhew/Biology%20Notes/transport%20notes_files/image001.gif
5. Result of this anatomy of phospholipid bilayer is:
• polar meaning water loving
(hydrophilic)
• phosphate heads orient themselves
towards the cytoplasm and
extracellular fluids(fluids on outside
of cell which contain water)
6. Result of this anatomy of phospholipid bilayer is:
•nonpolar meaning water hating
(hydrophobic)
•lipid tails have an attraction for
each other and orient themselves
towards each other in the middle of
the bilayer
Resulting in something like this:
9. Molecules found in plasma membrane:
2. Proteins
float in the middle of the bilayer
there are three types
10. Molecules found in plasma membrane:
2. Proteins
A. Channel proteins
• protrude both sides
• have channels through them that
let things in and out
http://kentsimmons.uwinnipeg.ca/cm1504/Image133.gif
11. Molecules found in plasma membrane:
2. Proteins
B. Glycoproteins - exterior
• composed of sugar and protein
• used as markers for recognition
http://www.ideacenter.org/stuff/contentmgr/files/e27b080d92450837e43d44bf73780847/misc/glycoprotein.jpg
12. Molecules found in plasma membrane:
2. Proteins
C. Receptor proteins
• receive messages by chemical means
from other cells
• example type II diabetes
http://www.scq.ubc.ca/wp-content/uploads/2006/07/transduction.gif
13. Molecules found in plasma membrane:
3. Cholesterol
• composes 1/3 of layer
• is nonpolar so found in middle
• gives firmness to layer
http://www.uic.edu/classes/bios/bios100/lectf03am/cholesterol.jpg
http://www.google.com/imgres?imgurl=http://people.csail.mit.edu/seneff/lipid_bilayer.jpg&imgrefurl=http://people.csail.mit.edu/seneff/statins_muscle_damage_heart_failure.html&usg=__tynxmR7yV
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2Bin%2Bplasma%2Bmembrane%26um%3D1%26hl%3Den%26rlz%3D1T4GZHY_enUS231US231%26tbs%3Disch:1&ei=s4MsTNb5I5GTkAXVgfWYCw
16. Physiology (functions) of plasma
membrane
delimits cell – holds it together
provides receptors -sense the
environment receiving messages
controls what moves in and out of
the cell or selective permeability
24. Types of diffusion in the plasma
membrane
A. Simple diffusion
unassisted process
solutes are lipid-soluble
materials or small enough to
pass through membrane pores
25. Types of diffusion in the plasma membrane
1. Simple diffusion
Remember most of membrane
is lipid (nonpolar) and nonpolars
dissolve nonpolars so fat
molecules move easily through
membrane
26. Types of diffusion in the plasma membrane
A. Simple diffusion
B. Osmosis
simple diffusion of water
Highly polar water easily
crosses the plasma
membrane
27. Types of diffusion in the plasma membrane
A. Simple diffusion
B. Osmosis
C. Facilitated/Mediated
diffusion/transport
Substances require a carrier
protein for passive transport
Carrier protein accepts a
certain shaped molecule
31. Types of diffusion in the plasma membrane
A. Simple diffusion
B. Osmosis
C. Facilitated/Mediated diffusion/transport
3 conditions for regulating mediated transport:
i. Specificity – made for specific molecule
ii. Competition – similar shapes compete for
same carrier, greater concentration wins
iii. Saturation – all carriers are full
32. Membrane Transport
There are two basic types of transport in the cells:
1. Passive transport
2. Active transport
The cell must provide metabolic
energy
includes large non-lipid soluble
molecules and the use of the
sodium-potassium pump
33. Membrane Transport
There are two basic types of transport in the cells:
1. Passive transport
2. Active transport
Metabolic energy comes from the
molecule abbreviated ATP
ATP = Adenosine Triphosphate
Energy released when ATP looses a
phosphate group and becomes ADP
34. Types of Active Transport
A. Pump – carrier protein
will grab molecule and
pump it against the
concentration gradient
(low to high)
37. Types of Active Transport
B. Endocytosis – the
process by which large
molecules are taken
into the cell
38. Types of Active Transport
Types of Endocytosis
i. Pinocytosis
Means “water drinking”
A mechanism by which cells
ingest extracellular fluid and its
contents (proteins)
Membrane pinches to form
vesicle containing protein
41. Types of Active Transport
Types of Endocytosis
ii. Phagocytosis
Means “cell eating”
The engulfing of microorganisms
or other cells and foreign
particles
Not all cells can do this
Most common in body are
white blood cells – defense