Membranes Notes (Class & NJCTL) Flashcards
the term membrane most commonly refers to a …., …-like structure that …. two fluids
thin; film-like; separates
membranes act as a … for biological systems, surrounding protobionts, cells, and organelles
container
the most important lipid that composes the majority of biological membranes is the …
phospholipid
the amphiphilic nature of these lipids cause them to naturally form a
spherical bilayer.
phospholipids form two … lines with their hydrophobic ends in between. the hydrophobic ends are protected from the …. by the hydrophilic ends, creating a ….
parallel; water; bilayer
in animals, cholesterol inserts itself …. into the … in the same orientation as the phospholipid
toward the hydrophobic tail; membrane
cholesterol …. the first few hydrocarbons in the phospholipid, making the bilayer more …, and impenetrable to … molecules
immobilizes; stable; water
membranes act as …. barriers, allowing some particles or chemicals to pass through, but not others
selectively permeable
the properties of the phospholipid bilayer dictate what can …. a membrane
pass through
when phospholipids come together, they create a wall that is tightly packed with a core that is …. However, the individual molecules are not fixed and small …. form as they fluidly move around in the membrane (this is what allows other …. to ….)
nonpolar; gaps; molecules; enter
charged particles …. through the membrane
do not pass
water passes through the membrane because it is very …, and is only ….
small; weakly polar
… molecules or …. molecules will not make it through a lipid bilayer
large; charged
hydrophobic molecules that pass through membrane:
O2, CO2, N2, steroids
small uncharged polar molecules that pass through the membrane:
H2O, glycerol, urea, ethanol
large uncharged polar molecules that DO NOT pass through the membrane:
glucose, sucrose
for important things like sugar and nucleic acids and proteins and sodium that can’t pass through the membrane, … aid in their transportation
embedded (integral) proteins
integral proteins can be …. (…. transport) or …. (…. transport) and are specific to … being transport
channels; passive; pumps; active; one item
proteins embedded in the cell membrane facilitate the movement of large or charged molecules through the barrier. by doing this, the internal chemistry of the cell becomes far different than its
surroundings
the pattern of lipids and proteins in the cell membrane is referred to as the …. model
fluid mosaic
…. proteins stay on only one side of the membrane, but can flip-flop
peripheral
…. proteins pass through the … and often span the membrane from one end to the other
integral; hydrophobic core
proteins in the plasma membrane can … within the bilayer. they are much ….than lipids and move more …. throughout the fluid mosaic
drift; larger; slowly
…. have a carbohydrate attached to a protein and serve as points of attachment for other …, …., …., and many other ….
glycoproteins; cells; bacteria; hormones; molecules
…. are lipids with a carbohydrate attached. Their purpose is to provide … and to act in …
glycolipids; energy; cellular recognition
an integral protein forms a …. that allows specific substances to diffuse across the membrane, even if they are … or have ….
pore; large; charge
antibodies are embedded in cell membranes and bind to antigens on the surface of foreign cells. What type of molecule is an antibody?
glycoprotein
in animal cells, water moves from areas of low solute concentration to areas of high solute concentration during osmosis. In plants, bacteria, and fungi, however, the cell wall exerts a force on the …. of the cell and affects the … of water through the cell membrane.
internal environment; net flow
the effects of solute concentration and the pressure provided by the cell wall are incorporated into a quantity called
water potential
osmosis moves water from areas of …. water potential to areas of …. water potential
high; low
water potential is calculated as follows:
water potential = pressure potential + solute potential
water potential is measured in …. or ….
megapascals; bar
1 MPa = …. bar
10
animal cells do not have cell walls so pressure potential =
0
solute potential is dependent upon …. and …. of solute. Its value can be determined using the following equation: ….
type; concentration; -iCRT
R = pressure constant: …. Lbar/ molK or …. L*MPa/ mol *K
0.0831; 0.00831
every biological cell is surrounded by an aqueous solution containing hundreds, maybe thousands of different …. in a variety of …
chemicals; concentrations
the cell’s membrane has ….. to maintain an internal environment which will allow the cell to perform its functions properly
protein regulators
the …. allow only specific chemicals, in specific ….. into the cell
membrane proteins; concentrations
homeostasis: the regulation of an …, even when the external conditions change
internal condition
larger molecules and ions that cannot squeeze between the phospholipids need the help of a ….. This is called ….
transport protein; facilitated diffusion
in facilitated diffusion, particles move from an area of … to … concentration with the help of a ….
high; low; transport protein
since the substances are going with the natural concentration gradient, facilitated diffusion is a type of …. transport: …. is needed
passive; no energy
in facilitated diffusion, transport proteins …. the passive transport of molecules across the plasma membrane
speed
transport proteins allow passage of …. across the membrane
hydrophilic substances
channel proteins, are one type of ….. that provide …. that allow a specific molecule or ion to cross the membrane
transmembrane transport proteins; corridors
carrier proteins, are another type of ….. that …. slightly when a specific molecule …. in order to help move that molecule across the membrane
transmembrane transport proteins; change shape; binds to it
active transport uses …. to move solutes through a …. against their ….
energy; transport protein; gradients
active transport requires …
energy
active transport is performed by specific …. embedded in the membranes
proteins
…. proteins can also be used in active transport when they are moving specific molecules …. their concentration gradients
carrier; against
the sodium potassium pump is an example of the active transport mechanism. This system is utilized in every animal cell to transport Na+ and K+, maintaining a relatively … concentration of potassium and relatively …. concentration of sodium inside the cell
high; low;
(sodium potassium pump) step 1: the pump, binds …., and then binds 3 ….
ATP; intracellular NA+ ions
(sodium potassium pump) step 2: ATP is …, leading to …. of the pump and subsequent release of …
hydrolyzed; phosphorylation; ADP
(sodium potassium pump) step 3: a conformational change in the pump exposes the …. ions to the ….
Na+; outside
(sodium potassium pump) step 3: The phosphorylated form of the pump has a low affinity for …. ions, so they are ….
Na+; released
(sodium potassium pump) step 4: the pump binds 2 …. ions. this causes the … of the pump, reverting it to its previous conformational state, transporting the …. into the cell
extracellular K+; dephosphorylation; K+ ions
(sodium potassium pump) step 5: the unphosphorylated form of the pump has a higher affinity for … ions than …. ions, so the two bound …. ions are …. ATP binds, and the process starts again
Na+; K+; K+; released
ATP synthase is an integral protein used to generate ATP, by allowing the flow of hydrogen ions across the membrane. This is an example of what type of transport?
facilitated diffusion
(components of cell membrane) hydrophobic substances can typically pass through the membrane with …. energy, as they are similar to the …. that make up the center of the phospholipid bilayer
no; hydrophobic tails
(components of cell membrane) cholesterol moderates the …. of the cell membrane. At high temperatures, it prevents the cell membrane from becoming too …. through …. it, and at low temperatures, it prevents …. by obstructing … between particular phospholipid tails
fluidity; fluid; stiffening; freezing; contact
(components of cell membrane) Extracellular matrix (ECM): the extracellular matrix is a protective matrix located just outside of the bilayer, consisting of … and …
proteins; polysaccharides
(components of cell membrane) The fibers of the ECM hold …. in place. For insatnce, fibronectin binds to the protein integrin in the cell membrane.
integral proteins
(components of cell membrane) amino acids in the ECM form …. that attach to proteins, forming …. which participate in cell …. and guide cell …. Overall, the ECM provides … to the plasma membrane and aids in …
polysaccharides; proteoglycans; signaling; migration; support; intercellular communication
(components of cell membrane) integral proteins are a permanent component of the membrane. They tend to span through the hydrophobic core and have a variety of functions. They can act as … or …. proteins for transporting molecules, as cell … proteins, …. to bring about cellular responses, …. to maintain …., or …. proteins to help … cells
channel; carrier; recognition; receptors; enzymes; metabolism; junction; join
(components of cell membrane) peripheral proteins are at the exterior of the cell membrane and can detach from it. they have similar functions as
integral proteins
cell membranes are fluid due to the …. residues that give it an …. consistency
unsaturated fatty acid; oil-like
with a greater concentration of unsaturated fatty acids, the cell membrane’s fluidity will
increase
The mosaic component of the model is because there are a large number of …., which can eventually change their …. (although it was found that many of these are associated with the ECM and/or cytoskeleton, which helps hold them in place)
embedded proteins; positions
cell membranes separate a cell’s content from its …., enabling chemcial reactions within the cell to occur undisrupted
external environment
cell membranes inhibit the loss of important cell materials, including …., …., …., …., and ….
proteins; nucleic acids; carbohydrates; organic monomers; ATP
commonalities between cell membranes of past and now: …. (component of … in ….), monitor …. —> needed in all cells in order to be living, regulate …. (….)
cytochrome C; electron transport chain; mitochondria; resting membrane potential; energy; ATP synthase
(important functions of the cell membrane for the cell) acts as a … from outside disruptions and therefore protects interior
barrier
(important functions of the cell membrane for the cell) regulates … of … into and out of the cell
transport; molecules
(important functions of the cell membrane for the cell) receives … from the environment and reacts to these
signals
(important functions of the cell membrane for the cell) glycoproteins and glycolipids that are a component of the cell membrane … the cell and therefore allow it to …. with other cells (e.g. white blood cells in immune system)
mark; communicate
(important functions of the cell membrane for the cell) involved in …. due to presence of proteins
metabolic processes
(important functions of the cell membrane for the cell) …. allow for movement of things
vesicles
if a cell grows beyond a certain limit, not enough material will cross the membrane …. to sustain the cell. rate of …
quickly enough; transport decreases
resting membrane potential is the …. across the cell membrane when the cell is at rest
voltage difference
resting potential is determined by … of … across the membrane, particularly referencing the uneven distribution of .. between the inside and outside of the cell
concentration gradients; ions; ions
resting potential: transporting ions … their concentration gradient; suggests that interior of cell is more … than the outside of the cell (typically … millivolts- mV)
up; negative; -70
active transport incorporated in movement of ions for resting potential, as ions are moving
against their gradients
for membrane potential, reference point is … of the cell, and the potential here looks at …
outside; gradients
water potential references the tendency of water to move in a particular manner. this is defined as the … per mole of water and is influenced by … and ….
free energy; solute and prssure potential
solute potential relates to …. and pressure potential refers to the … or … pressure on a solution
solute concentration; positive; negative
potential for water potential also looks at
gradients
resting membrane potential relates to water potential because they both relate to …. and both help to maintain …
concentration gradients; homeostasis
potentials are regulated through either
active/passive transport
osmoregulation: “The maintenance of constant osmotic pressure in fluids of an organism by the control of … and …..”
water; salt concentratoins
countercurrent exchange/ countercurrent multipliers: usiing cell membranes as a ….; heat or some other component crosses between two … in … directions
gradient; flowing bodies (fluids); opposite
respiratory/circulatory countercurrent exchange in sharks: oxygen-rich water passes over the gills in the … direction as oxygen-poor blood such that the blood ….
opposite; gains oxygen
with respiratory countercurrent exchange, an equilibrium is … reached as the blood is ceaselessly encountering water that has a …. than the blood does
never; higher oxygen content
this countercurrent exchange also allows for the … amount of oxygen to pass from the water and into the blood
maximum
countercurrent exchange involves a … alignment
parallel
thermal regulation & countercurrent exchange: when blood travels back to the heart, it is heated by way of …. and …. The heat is then transferred, through …., to …. blood as it passes through veins and arteries. the blood in veins and arteries flow in opposite directions, allowing for the countercurrent heat exchange
muscle contraction; metabolic processes; thermal conduction; arterial;
thermal regulation & countercurrent exchange: alignment is also …. (important- …., allows for ….)
parallel; juxtaposition; heat exchange
thermal regulation & countercurrent exchange: …. carry blood away from the heart; …. carry blood to the heart, …. are warmer than ….
arteries; veins; veins; arteries
countercurrent exchange is intended to maintain a
concentration gradient
sharks are …. (influenced by environmental temperatures) whereas humans are
ectothermic; endothermic
glucose is … transported, but is too big, so it uses … proteins
passively; carrier
