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51 Cards in this Set

  • Front
  • Back
cell membrane is also called ... or ...
plasma membrane
plasmalemma
the cell membrane maintains the integrity of the cell and mediates ... with the extracellular environment and other cells
communication
cell membranes communicate with each other through 2 ways, which are...
-gap junctions
-secreted substances (receptors and ligands)
cell membrane can also set up an ... because it generates differences in ion concentrations between the interior and exterior of the cell
electrical gradient
the plasma membrane is about #-# nm in diameter, below the resolution of the light microscope and is, therefore, only visible by ...
8-10
transmission electron microscopy (TEM)
within the lipid bilayer of the cell membrane are associated ... and ...
proteins
glycoproteins
the trilaminar adherens is dark staining due to osmium. It stains the ... of the cell membrane
phosphate heads
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
middle electron lucent layer
the 2 types of proteins associated with the cell membrane are ... membrane proteins and ... membrane proteins.
integral
peripheral
which membrane proteins interact with the hydrophobic areas of the bilayer?
integral
which membrane proteins are loosely associated with the membrane and can easily be removed?
peripheral
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
glycoproteins
glycolipids
the 3 functions of the glycoproteins and glycolipids are ...
-cell to cell recognition
-receptor function
-repel other RBCs
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 ...
glycocalyx
cell coat
the carbohydrate components are stained with ...
lithinium red
these extracellularly located carbohydrates contribute to the establishment of an extracellular microenvironment that have specific functions in ..., cell ... and ..., and as ... for hormones.
metabolism
recognition and association
receptor sites
integral membrane proteins can move ... within the plane of the lipid bilayer (usually to be distributed evenly throughout the cell)
laterally
This lateral movement of proteins within the lipid bilayer may be important in the mediation of ... (e.g., receptor proteins coupling to transducer proteins)
hormone response
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)
cytoskeletal
... allows cells to respond to specific chemical signals?
cell receptors
Receptors (integral membrane proteins) convey their signal to various ... internal messengers
hydrophilic
receptors bind to ...
ligands
Water, which is able to form hydrogen bonds internally, like to form complex cage-like structures known as ...
clathrates
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
destablilization
reorganization
H20 wants to maximize binding to ...
itself
The presence of nonpolar molecules in water results in reorganization in the "caging" or ... formation, of water molecules around the nonpolar solutes
clathrate
grouping hydrophobic molecules together into aggregates causes ... between water molecules.
less disruption of hydrogen bonds
most eukaryotic membranes are composed of 4 major phospholipids, which are:
phosphatidylcholine, ethanolamine, serine, and sphingomyelin
phospholipids are ..., meaning they have both polar and nonpolar characteristics
amphipathic
..., ..., 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
the lipid bilayer can form a circle, called a ... or ...
liposome
micelle
Phospholipids in membranes usually contain ... saturated fatty acids (longer saturated fatty acids would be solids at physiologic temperatures) and ... unsaturated fatty acids
C16
longer-chain
in addition to phospholipids, membranes contain ... and various ... as well
cholesterol
glycolipids
... are important cell surface molecules involved in cell-cell recognition, cell adhesion, and cell receptors and signaling.
glycolipids
... makes up as much as 1/2 of the plasma membranes (lower proportions in intracellular membranes) and mostly affects membrane structure and fluidity.
cholesterol
cholesterol is also amphipathic like ...
-carbon ring structure = nonpolar
-hydroxyl (-OH) group = polar
-aligns in membranes similar to ...
phospholipids
phospholipids
cholesterol separates phospholipids so that the fatty acid chains can't come too close together and ...
crystallize
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
these lipid rafts serve as important attachment sites for proteins involved in ... Invaginated lipid raft domains are called ...
cell signaling
caveolae
Lipids within the membrane (are/are not) uniformly distributed.
are not (membrane asymmetry)
Glycolipids, phosphatidylcholine (PC), and sphingomyelin are mostly found on the ... leaflet of the membrane.
outer
negatively charged phospholipid head groups (PE, PS, PI) are more abundant on the ... leaflet of the membrane
inner
in which 2 regards to membranes differ?
-when comparing plasma membranes from different cell types
-when comparing cellular membranes from different organelles within the same cell
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
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.
fluid mosaic model
functions of ... membrane proteins include ion channels, pumps, transporters, and G-protein coupled receptors.
integral
functions of ... membrane proteins include G proteins, enzymes, receptors
peripheral
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
several transmembrane alpha-helices can collectively form a channel in the membrane, which allows for movement of ... or ... substances across the nonpolar membrane
ionic
polar
... 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
... proteins dissociate following treatment with a polar reagent, such as a solution with an elevated pH or high salt concentrations.
peripheral