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Flashcards in Membrane Components Deck (21)
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Triacylglcerols and free fatty acids

act as a phospholipid precursors and are found in low levels in the membrane

storage lipids involved in human metabolic processes
3 fatty acid chain esterified to a glycerol molecule



replace one fatty acid with a phosphate molecule, which is often linked to to other hydrophilic groups
used for membrane synthesis
can produce a hydrophilic surface layer on lipoproteins

phospholipids are the primary component of cell membranes - serve not only as structural roles but can also serve as second messengers in signal transduction



present in large amounts and contributes to membrane fluidity and stability
necessary in the synthesis of all steroids, which are derived from cholesterol

occupies space between adjacent phospholipids and prevents the formation of crystal structures in the membrane, increasing fluidity.



present in very small amounts, if at all; they are most prevalent in plants and function in waterproofing and defense.
provide membrane stability
very hydrophobic
composed of a long chain fatty acid and a long chain alcohol
can provide both stability and rigidity within the non polar tail region only.
most serve an extracellular function in protection or waterproofing


Proteins located within the cell membrane act as

transporters, cell adhesion molecules and enzymes


Transmembrane proteins

can have one or more hydrophobic domains and are most likely to function as receptors or channels.
pass completely through the lipid bilayer

ex: transporter, channels and receptors


Embedded proteins

most likely part of a catalytic complex or involved in cellular communication
associated with only the interior of the plasma membrane; partially hydrophobic.


Membrane associated proteins

act as recognition molecules or enzymes

may be found on G proteins in G protein coupled receptors


Carbohydrates can form what kind of coat?

glycoprotein coat and also function in cell recognition


Extracellular ligands can bind to membrane receptors and function as...

channels or enzymes in second messenger pathways


Gap junctions

allow for the rapid exchange of ions and other small molecules between adjacent cells
doesn't transfer proteins


Tight junctions

prevent solutes from leaking into the space between cells via paracellular route, but do not provide intercellular transport
Found in epithelial cells

can limit permeability enough to create a transepithelial voltage difference based on differing concentrations of ions on either side of the epithelium.

To be effective, tight junctions muse form a continuous band around the cell, otherwise fluid could leak through spaces between tight junction.


Desmosomes and hemidesomsomes

anchor layers of epithelial tissue


Unsaturated fatty acids

tend to have one or more double bonds and exist in liquid form at room temperature


Saturated fatty acids

"less healthy"
found in processed food

main components of animal fats and tend to exist as solids at room temperature

decrease the overall membrane fluidity



important constituents of cell membranes
do not contain glycerol but are similar structure to glycerophospholipids in that the contain a hydrophilic region and two fatty acid - derived hydrophobic tails.



act as signaling and recognition molecules


membrane recepts tends to be which proteins?

transmembrane proteins.


cell adhesion molecules (CAMs)

proteins that allow cells to recognize each other and contribute to proper cell differentiation and development



bind adjacent cells by anchoring to their cytoskeletons. Formed by interactions between transmembrane proteins associated with intermediate filaments inside adjacent cells.
Found at the interface between two layers of epithelial tissue



main function is to attach epithelial cells to underlying (basement) membranes