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51 Cards in this Set
- Front
- Back
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cell membrane is also called ... or ...
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plasma membrane
plasmalemma |
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the cell membrane maintains the integrity of the cell and mediates ... with the extracellular environment and other cells
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communication
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cell membranes communicate with each other through 2 ways, which are...
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-gap junctions
-secreted substances (receptors and ligands) |
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cell membrane can also set up an ... because it generates differences in ion concentrations between the interior and exterior of the cell
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electrical gradient
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the plasma membrane is about #-# nm in diameter, below the resolution of the light microscope and is, therefore, only visible by ...
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8-10
transmission electron microscopy (TEM) |
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within the lipid bilayer of the cell membrane are associated ... and ...
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proteins
glycoproteins |
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the trilaminar adherens is dark staining due to osmium. It stains the ... of the cell membrane
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phosphate heads
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by TEM, the plasma membrane consists of a ... sandwiched between inner and outer electron-dense lines, which reflects the bilayer arrangement of the amphipathic phospholipids
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middle electron lucent layer
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the 2 types of proteins associated with the cell membrane are ... membrane proteins and ... membrane proteins.
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integral
peripheral |
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which membrane proteins interact with the hydrophobic areas of the bilayer?
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integral
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which membrane proteins are loosely associated with the membrane and can easily be removed?
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peripheral
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the membrane surface also contains a variety of carbohydrate moieties like ..., which are sugar molecules attached to proteins ("glycosylated"), and ..., which are sugar molecules attached to membrane lipids
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glycoproteins
glycolipids |
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the 3 functions of the glycoproteins and glycolipids are ...
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-cell to cell recognition
-receptor function -repel other RBCs |
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The carbohydrate components of integral and peripheral membrane proteins (glycoproteins) and to lipids (glycolipids) of the membrane bilayer, are exclusively located on the extracellular surfaces of cell membranes and form a layer at the surface of the cell called a ... or ...
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glycocalyx
cell coat |
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the carbohydrate components are stained with ...
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lithinium red
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these extracellularly located carbohydrates contribute to the establishment of an extracellular microenvironment that have specific functions in ..., cell ... and ..., and as ... for hormones.
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metabolism
recognition and association receptor sites |
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integral membrane proteins can move ... within the plane of the lipid bilayer (usually to be distributed evenly throughout the cell)
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laterally
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This lateral movement of proteins within the lipid bilayer may be important in the mediation of ... (e.g., receptor proteins coupling to transducer proteins)
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hormone response
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movement of these proteins are restricted by their interaction with ... proteins located in the cells cytoplasm or with other proteins located in the extracellular matrix or adjacent cells (e.g., junctions)
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cytoskeletal
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... allows cells to respond to specific chemical signals?
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cell receptors
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Receptors (integral membrane proteins) convey their signal to various ... internal messengers
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hydrophilic
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receptors bind to ...
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ligands
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Water, which is able to form hydrogen bonds internally, like to form complex cage-like structures known as ...
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clathrates
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hydrophobic interactions are maintained not so much by direct interaction between the nonpolar solutes, but by the ... (increased entropy) and ... of the surrounding water molecules
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destablilization
reorganization |
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H20 wants to maximize binding to ...
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itself
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The presence of nonpolar molecules in water results in reorganization in the "caging" or ... formation, of water molecules around the nonpolar solutes
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clathrate
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grouping hydrophobic molecules together into aggregates causes ... between water molecules.
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less disruption of hydrogen bonds
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most eukaryotic membranes are composed of 4 major phospholipids, which are:
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phosphatidylcholine, ethanolamine, serine, and sphingomyelin
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phospholipids are ..., meaning they have both polar and nonpolar characteristics
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amphipathic
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..., ..., and ... are polar molecules (make up the polar "head" of a phospholipid).
the fatty acid "tails" are nonpolar hydrocarbon chains that must be shielded from water. |
choline
ethanolamine serine |
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the lipid bilayer can form a circle, called a ... or ...
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liposome
micelle |
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Phospholipids in membranes usually contain ... saturated fatty acids (longer saturated fatty acids would be solids at physiologic temperatures) and ... unsaturated fatty acids
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C16
longer-chain |
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in addition to phospholipids, membranes contain ... and various ... as well
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cholesterol
glycolipids |
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... are important cell surface molecules involved in cell-cell recognition, cell adhesion, and cell receptors and signaling.
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glycolipids
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... makes up as much as 1/2 of the plasma membranes (lower proportions in intracellular membranes) and mostly affects membrane structure and fluidity.
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cholesterol
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cholesterol is also amphipathic like ...
-carbon ring structure = nonpolar -hydroxyl (-OH) group = polar -aligns in membranes similar to ... |
phospholipids
phospholipids |
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cholesterol separates phospholipids so that the fatty acid chains can't come too close together and ...
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crystallize
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cholesterol provides a more solid bed for membrane proteins to stick to at the cell surface
-cholesterol and sphingomyelin form ... (microdomains) with the membrane |
lipid rafts
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these lipid rafts serve as important attachment sites for proteins involved in ... Invaginated lipid raft domains are called ...
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cell signaling
caveolae |
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Lipids within the membrane (are/are not) uniformly distributed.
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are not (membrane asymmetry)
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Glycolipids, phosphatidylcholine (PC), and sphingomyelin are mostly found on the ... leaflet of the membrane.
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outer
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negatively charged phospholipid head groups (PE, PS, PI) are more abundant on the ... leaflet of the membrane
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inner
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in which 2 regards to membranes differ?
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-when comparing plasma membranes from different cell types
-when comparing cellular membranes from different organelles within the same cell |
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lipid asymmetry is caused by:
-... of lipids within bilayer -... of lipids (mediated by flippase) from one side of the bilayer to the other (especially PC, SM, and cholesterol) |
lateral diffusion
flipping of lipids |
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According to the ... of Singer and Nicholson, biological membranes can be considered as a 2-D liquid where all lipid and protein molecules diffuse more or less freely into their respective positions within the membrane.
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fluid mosaic model
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functions of ... membrane proteins include ion channels, pumps, transporters, and G-protein coupled receptors.
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integral
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functions of ... membrane proteins include G proteins, enzymes, receptors
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peripheral
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integral membrane proteins:
-can be transmembrane or intramembrane -... is the most common structural motif found in integral proteins -... found in some prokaryotic membranes (called porins) |
alpha-helix
beta-barrels |
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several transmembrane alpha-helices can collectively form a channel in the membrane, which allows for movement of ... or ... substances across the nonpolar membrane
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ionic
polar |
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... membrane proteins are attached to the membrane using one of 6 possible attachment strategies:
-isoprenoid tails (15-carbon farnesyl cholesterol derivative) -myristoyl tails (14-carbon saturated fatty acid) -glycosylphosphatidylinositol (GPI) anchor -electrostatic interactions -partial penetration of bilayer -association with integral proteins |
peripheral
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... proteins dissociate following treatment with a polar reagent, such as a solution with an elevated pH or high salt concentrations.
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peripheral
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