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Date Submitted: 07/17/2015 04:19 AM
PHYSIOLOGY
CELL MEMBRANE AND TRANSPORT (1st Lec)
DR. MILAGROS B. RABE
OBJECTIVES
1.
2.
3.
4.
5.
6.
I.
• In 1972, J. Singer and G. Nicolson proposed that the
membrane is a mosaic of proteins dispersed within the bilayer
Give the functions of the cell membrane
Describe the Fluid-Mosaic model of the plasma
membrane.
Give the composition of the plasma membrane
-Identify the different lipids and their roles
-Enumerate the types of proteins and their functions
-Give the roles of carbohydrates in the membrane.
Describe the membrane transport systems.
Describe the transmembrane transport.
-Explain Fick’s Law of Diffusion.
-Differentiate active and passive transport.
-Give examples of each type of transport systems
Describe transport across the cell membrane.
-Classify the types of endocytosis.
-Describe exocytosis.
JUNE
18
2014
Cell
FLUID MOSAIC MODEL
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Fluid Mosaic Model – cellular membranes are fluid
structures
o
o
Lipids and Proteins may move freely in the
6/18/2014
membrane but they go from one
phospholipid to another (“flip-flop”) at a slow
rate.
Not all membrane components can be
diffused through the membrane.
B. MEMBRANE STRUCTURE
The most abundant constituents of the cellular
membrane are the proteins and phospholipids.
II.
CELL MEMBRANE
A. FUNCTIONS OF CELL MEMBRANE
-‐
-‐
-‐
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regulate TRANSPORT of molecules into and out of
cell (selective permeability)
cell RECOGNITION (surface antigens)
cell COMMUNICATION (neurotransmitters,
hormones, signal transduction)
TISSUE ORGANIZATION – temporary and
permanent cell junctions; cell adhesion molecules
ENZYMATIC ACTIVITY – when external internal
Determination of cell SHAPE – link to cytoskeleton
-‐
-‐
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1. Phospholipids
Consists of a polar head group and two nonpolar,
hydrophobic fatty acyl chains
Tends to orient with their hydrophobic fatty acyl
chains away from contact with...