Adipose tissue vs skeletal muscle - ️️Adipose:
- ~ 90% lipids, small fraction of water
Skeletal:
- ~75% water
~18% protein
Cell membrane (plasma membrane) - ️️- double layer (lipid bilayer) with
phospholipids and protein molecules inserted in them
- Carbohydrates are attached to extr...
BMSC 207 Cell membranes
Adipose tissue vs skeletal muscle - ✔️✔️Adipose:
- ~ 90% lipids, small fraction of water
Skeletal:
- ~75% water
~18% protein
Cell membrane (plasma membrane) - ✔️✔️- double layer (lipid bilayer) with
phospholipids and protein molecules inserted in them
- Carbohydrates are attached to extracellular side
Sphingolipid chemical composition and function - ✔️✔️- sphingosine backbone with
fatty acid tail, as well as possible cholines, sugars, attached.
-Longer than phospholipids
- act as Lipid rafts of the cell membrane
Body cavities - ✔️✔️Cranial, thoracic, pelvic
Functional body compartments - ✔️✔️ECF, ICF, cells
Functions of a cell membrane - ✔️✔️- physical isolation separating ICF and ECF as
well as the cell from its environment
- Regulation of exchange with the environment; selectively permeable
- Communication between the cell and its environment ; proteins allow for responding
and interacting
- Structural support; proteins in the membrane make cell-to-cell connections (tissue)
and anchor the cytoskeleton
Cell membrane composition (% of each) - ✔️✔️- 55% proteins
- 45% lipids
- small amount of carbohydrates
- note not all membranes are the same
what determines the amount of protein a cell membrane contains? - ✔️✔️- The more
metabolically active the membrane is the more protein it contains
- how much energy it needs to produce
The 3 lipid types in the cell membrane and its % composition - ✔️✔️- Phospholipid;
approx 50%
- Sphingolipids; approx 30%
- Cholesterol; approx 20%
, Amphipathic - ✔️✔️has both a hydrophilic and hydrophobic side
Phospholipid bilayer - ✔️✔️flat, sheet layer, forms when environment is purely liquid
and no air
Micelles - ✔️✔️Spherical droplets of phospholipids; important in lipid digestion
Liposomes - ✔️✔️Spherical bilayers produced in a lab to get certain substances (ie
drugs) across a cell membrane. Has an aqueous center where the certain substance is
located
Phospholipid chemical composition and function - ✔️✔️- glycerol backbone with fatty
acid tail
- major lipid that makes up most of the cell membrane
Cholesterol Function - ✔️✔️-Increases viscosity, decreases permeability
- shimmies in between phospholipids ; extra security guard for the membrane
- makes membrane less delicate
Current cell membrane model is called - ✔️✔️fluid mosaic model
What does the extracellular surface of the cell membrane contain? - ✔️✔️-
glycoproteins and glycolipids;
- carbohydrates are attached either to proteins or lipids
How many different types of proteins does each cell have in its membrane? - ✔️✔️10-
50 different types
Integral proteins - ✔️✔️- tightly bound to the membrane, bound to fatty acid or external
GPI anchor
- you need to disrupt/damage the cell membrane to remove/isolate it
Integral protein roles - ✔️✔️- membrane receptors
- cell adhesion molecules
- transmembrane movement
- enzymes
- mediators of intracellular signalling
Peripheral protein roles - ✔️✔️- participate in intracellular signalling
- form submembraneous cytoskeleton
Lipid anchored proteins - ✔️✔️- commonly associated with sphingolipids
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