Neurophysiology Ion Channels and Transporters Quiz

False (B)

Cell-attached, Whole-cell, Outside-out, or Inside-out

<p>primary active transport</p> Signup and view all the answers

<p>Antiporter = Ions move in opposite directions Symporter = Ions move in the same direction Cotransporters = Use primary transport to facilitate movement</p> Signup and view all the answers

<p>They open in response to a ligand binding. (B)</p> Signup and view all the answers

<p>Which ions can pass through it</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>$\mathrm{\text{Moles of ions}} = \frac{Q}{F}$ (B)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>K+ ions become fully dehydrated and fit precisely into the filter's carbonyl oxygen coordination sites.</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>tetrameric</p> Signup and view all the answers

<p>Avogadro's number</p> Signup and view all the answers

<p>electric field</p> Signup and view all the answers

<p>Voltage-gated Kv channels = 40 genes Ca2+-activated (KCa) channels = 5 genes Two-pore (K2P) channels = 15 genes Inward-rectifying (KIR) channels = 15 genes</p> Signup and view all the answers

<p>Diffusion coefficient (D)</p> Signup and view all the answers

<p>Inactivation (D)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Drift Flux = Flow of particles due to electric field Diffusion Flux = Flow of particles due to concentration gradient Electrical Conductivity = Ability of a material to conduct electric current Mobility = Ease of movement of ions under an electric field</p> Signup and view all the answers

<p>Na+ ions have stronger interactions with water molecules, making it difficult for them to fully dehydrate and fit into the coordination sites.</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>mobility</p> Signup and view all the answers

<p>It increases above $E_R$. (A)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>V_m = E_R + \frac{I_m}{g_m} \cdot \left( 1 - e^{\left( \frac{- t}{\tau} \right)} \right)</p> Signup and view all the answers

<p>uniform</p> Signup and view all the answers

<p>Time constant (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>\Delta V_m(t) = I_m \cdot R_m \cdot \left( 1 - e^{\left( \frac{- t}{\tau} \right)} \right)</p> Signup and view all the answers

<p>Na+ channels decrease depolarization and increase hyperpolarization. (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>The rate of change of voltage is zero. (A)</p> Signup and view all the answers

<p>Restore balance between excitation and inhibition.</p> Signup and view all the answers

<p>positively</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>I = C * dV/dt</p> Signup and view all the answers

<p>Na+ channel = Decreases depolarization K+ channel = Increases depolarization</p> Signup and view all the answers

<p>Ibuprofen (C)</p> Signup and view all the answers

<p>Nernst</p> Signup and view all the answers

<p>Resistor = Charges move through Capacitor = Charges accumulate on both sides IV Curve = Describes current-voltage relationship Conductance = Proportional to the flow of current</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>I = ΔV / R (B)</p> Signup and view all the answers

<p>They are involved in burst firing and corticothalamic feedback.</p> Signup and view all the answers

<p>0.2</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>It is the membrane potential at which there is no net current flow for a given ion.</p> Signup and view all the answers

The movement of particles (ions) due to an electric field.

The movement of particles (ions) due to a concentration gradient, flowing from high concentration to low concentration.

The flow of particles due to the electric field (E): Jdrift = σ ⋅ E

The flow of particles due to a concentration gradient: Jdiff = - D ⋅ d[C]/dx

The number of moles of ions, calculated by dividing the charge (Q) by Faraday's constant (F).

The total number of ions, calculated by multiplying the moles of ions by Avogadro's number (NA).

The movement of ions across a membrane due to differences in concentration or electrical potential. The sum of drift and diffusion flux.

The process where ions move across a membrane, changing the electrical potential across the membrane.

The steady-state membrane potential is determined by the applied current and the membrane conductance.

The time constant represents the time it takes for the membrane potential to reach approximately 63% of its final value during a change in current.

The rate of change of membrane potential is directly proportional to the applied current and inversely proportional to the membrane capacitance. It also depends on the difference between the current membrane potential and the resting potential.

The change in membrane potential over time is described by an exponential function that approaches a steady-state value.

The voltage is uniform over the membrane surface, like a sphere bathed in a constant electric field.

The voltage varies along the length of the membrane, higher at one end and lower at the other, like a cylinder with different charges at each end.

The cell membrane acts like a parallel combination of resistance (due to ion channels) and capacitance (due to the membrane itself).

The membrane potential increases when the applied current exceeds the resting potential, causing the membrane conductance term to increase, thus slowing down the rate of change of membrane potential.

The resting membrane potential (V_rest) is the electrical potential difference across the cell membrane when the cell is at rest and not transmitting any signals. It is primarily determined by the concentration gradients of ions like potassium (K⁺), sodium (Na⁺), and chloride (Cl^-) across the membrane, and their relative permeability.

The Nernst Equation calculates the equilibrium potential for a specific ion across a membrane, based on its concentration gradient. It helps predict the direction of ion movement across the membrane if it were permeable only to that specific ion.

The Goldman-Hodgkin-Katz (GHK) Equation calculates the resting membrane potential by considering the contributions of all the permeant ions, taking into account both their concentration gradients and their relative permeabilities across the cell membrane.

The IV curve (current-voltage curve) of a neuron is a graphical representation of the relationship between the current flowing across the neuron's membrane and the voltage across it. It provides information about the neuron's electrical properties and its response to different stimuli.

The rate of change of voltage over time in a neuron is determined by the current flowing across the membrane. This is represented by the equation dV/dt = -I(V), where V is the membrane potential and I is the current. This relationship helps understand how a neuron's voltage changes in response to incoming signals.

A stable equilibrium in a neuron's IV curve represents a membrane potential where the current is zero and the voltage is not changing. The neuron is at rest and not actively responding to any stimuli.

An unstable equilibrium in a neuron's IV curve represents a membrane potential where the current is zero, but the voltage is at a point where any slight change will push the neuron away from this point, causing further change.

A resistor in a circuit allows charges to flow through it, with resistance controlling the rate of flow. The IV curve of a resistor is linear, meaning the current is directly proportional to the voltage difference.

A capacitor in a circuit stores electrical charge. It doesn't allow current through but accumulates charges on its plates. The IV curve of a capacitor is not linear, as the current is proportional to the rate of change of voltage.

A technique that controls the voltage across a membrane and measures the resulting current. This allows researchers to study how ion channels respond to changes in voltage.

A technique that controls the current flowing across a membrane and measures the resulting voltage. This allows researchers to study how ion channels affect the voltage across the membrane.

A single-electrode technique used when two electrodes can't be inserted, mimicking the voltage clamp with a patch clamp amplifier and feedback resistor.

A technique for studying ion channels by recording currents through single ion channels in a patch of membrane.

A patch-clamp configuration where the electrode is attached to the intact cell membrane. It measures single-channel or capacitive currents.

A technique that measures the opening and closing of ion channels by changing the voltage across the membrane and observing the changes in current.

A type of ion channel where the opening and closing of the channel is controlled by changes in membrane voltage.

The process by which ion channels open and allow ions to flow through the membrane. Different channels have different voltage dependencies.

A condition where ion channel function is disrupted, leading to changes in the electrical activity of cells.

The movement of ions into a neuron, causing a change in membrane potential towards a more positive value.

The movement of ions out of a neuron, causing a change in membrane potential towards a more negative value.

A type of epilepsy characterized by brief, generalized seizures caused by abnormal activity in the thalamocortical network.

The membrane of a neuron acts like a capacitor, storing electrical charge and resisting the flow of current.

The process by which a neuron generates a rapid, transient change in its membrane potential, allowing for communication with other cells.

An experimental method used to study the electrical properties of neurons by inserting electrodes into the cell and measuring changes in membrane potential.

Voltage-gated potassium channels are a type of ion channel responsible for regulating the flow of potassium ions (K+) across the cell membrane. They play a crucial role in maintaining the cell's resting membrane potential and generating action potentials in neurons and muscle cells. These channels are characterized by their sensitivity to changes in membrane voltage, opening when the membrane potential becomes more positive and closing when it becomes more negative.

Calcium-activated potassium channels (KCa channels) are a type of ion channel that opens in response to an increase in intracellular calcium concentration. They contribute to various physiological processes, including neurotransmitter release, muscle contraction, and smooth muscle relaxation.

Two-pore potassium channels (K2P channels) are unique ion channels comprised of two separate pore-forming subunits. Unlike other potassium channels, these channels do not require voltage or calcium for activation. They are constantly active and contribute to maintaining the resting membrane potential.

Inward rectifier potassium channels (KIR channels) are a type of potassium channel with unique properties that allow potassium ions to flow more easily into the cell than out of it. This inward rectification is due to their structure, which allows potassium ions to pass through more easily when the membrane potential is negative.

Potassium channels are remarkably selective for potassium ions, allowing them to pass through the channel's pore while effectively excluding other ions, like sodium. This selective permeability arises from the narrow selectivity filter, a region within the channel's pore that preferentially binds potassium ions.

The selectivity filter of a potassium channel is a narrow region within the channel's pore that is lined with carbonyl oxygens contributed by the protein subunits. When potassium ions enter the filter, they lose their hydration shell and become fully dehydrated. This dehydration is facilitated by the precise arrangement of the carbonyl oxygens that bind to the potassium ions, replacing the water molecules.

Sodium ions (Na+) are smaller than potassium ions and are strongly attracted to water molecules or anionic sites. As a result, they are more difficult to dehydrate compared to potassium ions. This means Na+ ions are less likely to pass through the narrow potassium channel, because they don't fit well in the selectivity filter and struggle to shed their hydration shell.

Sodium channels are also tetrameric proteins, consisting of four subunits that assemble to form a functional channel. These channels are involved in the transmission of nerve impulses, crucial for muscle contraction and other vital functions.