HUMB1000 Lecture Notes - Lecture 1: Fluid Mosaic Model, Extracellular Fluid, Fluid Compartments
19 Jun 2018
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Attaches cells to other cells and to the surrounding matrix
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Cells communicate with their environment through their cell
membrane
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Intra- and extracellular environment is different
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Determines what can move into and out of the cell (selectively
permeable)
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Difference in charge across membranes- membrane potential
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Structure= fluid mosaic model
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Lipid bilayer- phospholipids, cholesterol, proteins (channel,
carrier, ATP powered pumps)
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Boundary of cell- encloses and supports cell contents
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Separates intracellular vs extracellular materials
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Fluid Mosaic Model:
This term refers to the theory that the cell membrane is not a rigid
structure but is fluid (constantly moving) in nature and can change
its shape and, to some extent, its composition over time. For
instance, the nature of the phospholipid molecules are influenced by
diet and membrane proteins come and go depending on the
metabolic state of the cell
Plasma Membrane
Tuesday, 20 March 2018
10:51 PM
Cells 2 Page 1
Form a tiny channel through the plasma membrane
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Molecules of certain size, shape, charge can pass through
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Non-gate ion channel (always open)
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Gate ion channels (open of closed by certain stimuli ie: K/Na
pump)
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Channel Proteins
Tuesday, 20 March 2018
10:51 PM
Cells 2 Page 2
Also called transporters
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Specific binding sites
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Protein changes shape to transport ions or molecules
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Resumes original shape after transport
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Uniporters, symporters, antiporters
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Integral proteins move ions from one side of membrane to the
other
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Uniporter
Transport only one molecule
Symporter
The movement of two different ions or
molecules in the same direction across a
plasma membrane, via a carrier/channel
protein.
Antiporter
The movement of two different ions or
molecules in the opposite direction across a
plasma membrane, via a carrier/channel
protein.
Carrier Proteins
Thursday, 5 April 2018
11:13 AM
Cells 2 Page 3
Document Summary
Attaches cells to other cells and to the surrounding matrix. Cells communicate with their environment through their cell membrane. Determines what can move into and out of the cell (selectively permeable) Lipid bilayer- phospholipids, cholesterol, proteins (channel, carrier, atp powered pumps) Boundary of cell- encloses and supports cell contents. This term refers to the theory that the cell membrane is not a rigid structure but is fluid (constantly moving) in nature and can change its shape and, to some extent, its composition over time. For instance, the nature of the phospholipid molecules are influenced by diet and membrane proteins come and go depending on the metabolic state of the cell. Form a tiny channel through the plasma membrane. Molecules of certain size, shape, charge can pass through. Gate ion channels (open of closed by certain stimuli ie: k/na pump) Integral proteins move ions from one side of membrane to the other. Protein changes shape to transport ions or molecules.
