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:

8. Molecules found in plasma membrane:
1.Phospholipids – make up bilayer

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

15. Membrane
Transport

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

17. Selective permeability –
ability to let certain materials
in or out while restricting
others.

18. Membrane Transport
Membrane Transport –
movement of substance into and
out of the cell

19. Membrane Transport
There are two basic types of
transport in the cells:
1. Passive transport and
2. Active transport

20. Membrane Transport
1. Passive transport
 No energy is required
 includes diffusion, osmosis, and
facilitated or mediated transport

21. Passive Transport Processes
Diffusion
Particles tend to distribute
themselves evenly
Movement is from high
concentration to low concentration,
or down a concentration gradient

22. Passive Transport Processes

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

28. Diffusion through the Plasma Membrane

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)

35. Example: Sodium Potassium Pump

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

39. Pinocytosis
i

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

42. Phagocytosis

43. Types of Active Transport
C. Exocytosis
the transportation of
material from inside
the cell to outside the
cell
Golgi apparatus plays
a part

44. Exocytosis