Neurons, Sodium-Potassium Pump, Uniport & Cotransport Flashcards
the sodium potassium pump is an example of the active transport mechanism. This system is utilized in every animal cell to transport … and …, maintaining a relatively high concentration of …. and relatively low concentration of …. inside the cell.
Na+; K+; potassium; sodium
(sodium potassium pump) the pump binds … and then binds … intracellular … ions
ATP; 3; Na+
(sodium potassium pump) ATP is …, leading to … of the pump and subsequent release of …
hydrolyzed; phosphorylation; ADP
(sodium potassium pump) A … change in the pump exposes the Na+ ions to the …. The phosphorylated form of the pump has a low affinity for … ions, so they ….
conformational; outside; Na+; are released
(sodium potassium pump) The pump binds … extracellular … ions. This causes the … of the pump, reverting it to its previous … state, transporting the … ions into the cell.
2; K+; dephosphorylation; conformational; K+
(sodium potassium pump) The unphosphorylated form of the pump has a higher affinity for Na+ ions than K+ ions, so the two bound K+ ions are …. …. binds and the process …
released; ATP; repeats
neurons rely on the unequal distribution of … and … ions to …. (known as …) throughout the nervous system
sodium; potassium; transmit signals; action potentials
in a resting neuron (one not sending signals), the ionic gradient produced by the sodium-potassium pump generates a resting potential of … to … mV
-60; -80
a certain amount of sodium and potassium is always leaking across the membrane through leakage channels, but sodium potassium pumps in the membrane actively
restore the ions to the appropriate side
nerve impulses are passed along neurons by a … of the membrane. an action potential is triggered when the membrane potential increases to between …. and … mV
depolarization; -40;-55
when this … value is reached, … gates open causing these ions to move … the cell
threshold; sodium; into
the influx of Na+ triggers … to open, releasing … ions … the cell. This depolarization of the cell signals the next neuron in the pathway to …
K+ gated channels; potassium; from (outside of); depolarize
the neuron returns to its original state through the action of …. embedded in the membrane and the original concentration gradients are …
sodium/potassium pumps; reestablished
Uniport: when …. type of molecule moves in a … through the cell membrane, independent of other molecules
one; single direction
Symport (co-transporter): … kinds of molecules move in … direction at the same … through the cell membrane
two; the same; time;
Antiport (exchanger): … kinds of molecules move in the … direction through the cell membrane –> binding on … sides of the transport protein
two; opposite; opposite
antiport and symport can be … (but not always)
active transport
facilitated diffusion is
uniport
symport and antiport powered by the … of ….
breakdown; ATP
cotransport incorporates the movement of one type of ion or molecule …. its concentration gradient and one type of ion/molecule … its concentration gradient –> both … and …. transport
against; down; passive; active
sodium potassium pumps are an example of … due to the fact that they are moving in … directions across the membrane
antiport; opposite
ATP synthase is an enzyme complex in the membrane that contains a channel, making it both a … and an … protein
channel; enzymatic
As a channel, ATP synthase allows … to flow down its … gradient - a gradient based on the …. differences and …. across the cell membrane
H+; electrochemical; electrical potential; chemical concentrations
The movement of H+ into the cell provides the necessary … that allows for the production of ….
kinetic energy; ATP
ATP synthase transport is … in that only one type of substance, the …., are being transported through the channel, all moving in the … direction
uniport; hydrogen ions; same
Action potential defines a change in … across the … and consists of three stages: …, …, and …
polarity; axonal membrane; depolarization; repolarization; hyperpolarization
beginning with a resting membrane potential of -70 mV, a sufficiently large … is applied such that the threshold– the minimum change in … necessary for an action potential to occur– is reached and the … is initiated
stimulus; polarity; action potential
the first stage of an action potential is …, in which the intra-axonal portion of the membrane becomes …
depolarization; positive
Depolarization occurs because, when the threshold is reached, many … open, and there is an influx of … into the axon, causing the voltage to increase from … mV to … mV
sodium channels; sodium ions; -70; +40
the significant increase in voltage prompts … to open, while … close
potassium channels; sodium channels
potassium ions then leave the axon in a stage known as …., causing the voltage of the axon to return back to the … of … mV
repolarization; resting membrane potential; -70
however, the voltage continues to decrease, causing …, as the gated potassium channels are …
hyperpolarization; leaky
the axon again returns to -70 mV, due to the … that continually pump … ions out of the cell and …. ions into the cell
sodium/potassium pumps; 3 sodium; 2 potassium
dendrites: receive … (…)
signals; neurotransmitters
nerves … make contact with other nerves/muscles
do not
neurotransmitter: made up of …, suggests that dendrite must have … on the surface
proteins; protein receptors
node of
ranvier
openings of myelin sheath (…) coating the … –> fat because it is … and is …
fat; axon; insulating; slipper
myelin sheath helps to speed up
conduction
without myelin sheath, the signal is …., not going in same …
dispersed; line
action potential (…) always progresses in …. direction due to the … in previous node
saltatory conduction; a single; hyperpolarization
synapse: space between … and between … and …
nerves; nerves; muscles
examples of neurotransmitters: …, …, … (ACL)
dopamine; serotonin; acetylcholine
tetanus - …, leads to … –> muscles locked in …, leads to inability to …, trouble …, interrupting …, …
bacteria; lock jaw; contraction; swallow; breathing; speech; death
tetanus progresses as …, … not broken down in this case
bacteria divide; acetylcholine
node contains: … pump, …
sodium/potassium pump; voltage gated sodium & potassium channels
action potential jumps from … to …, but adjacent ones are never doing the same thing at the same time –> …
node; node; saltatory conduction
ion channels: proteins extending across the cell membrane, allowing for the passage of … into or out of the cell
ions
ion channels are specific to certain ions and are opened for a short amount of time in response to …, meaning that they are …
signals; gated
the transport of ions across ion channels is a form of … transport, as no … is required
passive; energy
two predominant groups of transport proteins:
channel & carrier proteins
both channel and carrier proteins create a passageway for molecules to enter/exit a cell, but carrier proteins …. when moving substances across the membrane
change their shape
ATP pumps are proteins that engage in the active transport of substances … their concentration gradients, powered by the … of … into … and …
against; hydrolysis; ATP; ADP; phosphate
Another example of active transport using an ATP pump is the … exchanger in the stomach
hydrogen/potassium
for the hydrogen/potassium exchanger, hydrogen ions are transported from a region of … concentration to a region of … concentration to make gastric juices especially acidic
low; high
with multiple sclerosis, myethin sheaths are damaged which impedes …. between different regions of the brain. This leads to various stages of …, …. problems, and general …
transmission of signals; paralysis; vision; weakness
