Physics of Biological Membrane

<p>The membrane potential is closer to the equilibrium potential of the ion with the highest permeability. (A)</p> Signup and view all the answers

<p>The resting membrane potential would become more positive, approaching the equilibrium potential of Na+. (C)</p> Signup and view all the answers

<p>The potassium equilibrium potential would become more positive. (D)</p> Signup and view all the answers

<p>The Goldman equation accounts for the permeability of the membrane to each ion. (C)</p> Signup and view all the answers

<p>A decrease in the permeability of the membrane to K+ would make the resting membrane potential more positive. (B)</p> Signup and view all the answers

<p>Blood viscosity is always higher than plasma viscosity, due to the presence of red blood cells. (A)</p> Signup and view all the answers

<p>10-2 - 10-5 Ω.cm-2 (D)</p> Signup and view all the answers

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

<p>Resistance is directly proportional to resistivity. (A)</p> Signup and view all the answers

<p>The plasma membrane is made of lipids, which are inherently poor conductors of electricity. (C)</p> Signup and view all the answers

<p>A dielectric material reduces the electric field between the capacitor's plates. (D)</p> Signup and view all the answers

<p>The viscosity of the membrane is constant regardless of temperature and density. (A)</p> Signup and view all the answers

<p>Body fluids are relatively good conductors of electricity, due to the presence of ions, but not as conductive as metals. (B)</p> Signup and view all the answers

<p>Potassium ions (K+) (C)</p> Signup and view all the answers

<p>It restores the resting potential by actively pumping sodium out and potassium into the cell. (A)</p> Signup and view all the answers

<p>During the depolarization phase. (D)</p> Signup and view all the answers

<p>It corresponds to the period where the membrane is not excitable, even with a strong stimulus. (D)</p> Signup and view all the answers

<p>The rate of change in membrane potential. (B)</p> Signup and view all the answers

<p>The electrical potential across a single nerve fiber over time. (D)</p> Signup and view all the answers

<p>It helps maintain the concentration gradient of sodium and potassium across the membrane. (C)</p> Signup and view all the answers

<p>Only if the stimulus is stronger than the initial one. (A)</p> Signup and view all the answers

<p>-76.7mV (D)</p> Signup and view all the answers

<p>26.7mV (D)</p> Signup and view all the answers

<p>The action potential size remains constant, regardless of the stimulus intensity. (D)</p> Signup and view all the answers

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

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

<p>-55mV (D)</p> Signup and view all the answers

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

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

<p>The thin thickness and high dielectric constant of the cell membrane. (D)</p> Signup and view all the answers

<p>They actively move ions against the electrochemical gradient, creating a potential difference. (D)</p> Signup and view all the answers

<p>The presence of pores that allow ion diffusion. (A)</p> Signup and view all the answers

<p>It contributes to the high capacitance of the membrane, despite its thinness. (C)</p> Signup and view all the answers

<p>It is significantly higher because of the high dielectric constant and thin thickness of the membrane. (A)</p> Signup and view all the answers

<p>An increase in the conductivity of the membrane. (B)</p> Signup and view all the answers

<p>They act as conductive plates in the parallel-plate membrane capacitor model. (C)</p> Signup and view all the answers

<p>Active transport pumps ions against their concentration gradient, maintaining the potential difference. (C)</p> Signup and view all the answers

<p>The electrical gradient for K+ is directed inward, opposing its tendency to move out. (D)</p> Signup and view all the answers

<p>The equilibrium reached between the concentration gradient and the electrical gradient for potassium. (A)</p> Signup and view all the answers

<p>They contribute to a small but consistent efflux of potassium ions, contributing to the membrane potential. (A)</p> Signup and view all the answers

<p>By pumping three sodium ions out for every two potassium ions in, it contributes to the net negative charge inside the cell. (C)</p> Signup and view all the answers

<p>The presence of a large amount of ATP within the cell. (C)</p> Signup and view all the answers

<p>By the combined effect of the concentration and electrical gradients across the membrane, as well as the permeability of the membrane to different ions. (A)</p> Signup and view all the answers

<p>Generating the electrical gradient across the membrane by pumping more negative ions out than positive ions. (B)</p> Signup and view all the answers

<p>Decreasing the permeability of the membrane to potassium ions. (D)</p> Signup and view all the answers

A measure of a material's ability to store electric energy in an electric field.

The ability of a capacitor to store electric charge, measured in microfarads (µF).

Consists of two conducting plates separated by an insulator (dielectric).

The capacitance of cell membranes influenced by their thinness and dielectric properties.

Molecular devices in cell membranes that actively transport ions against their gradient.

The process creating a difference in electric charge across a cell membrane, approx. -90 mV inside.

Loss of energy stored in the capacitor due to ion diffusion through the membrane.

Conductive fluids inside and outside cells that facilitate the flow of electric charge.

The ability of a membrane to resist flow, depending on its composition and temperature.

The thickness and stickiness of blood, influenced by plasma and hematocrit levels.

Describes the relationship between current, voltage, and resistance: V = IR.

Opposition to electric current, measured in ohms (Ω).

Materials that allow easy flow of electric current with low resistance.

Materials that oppose electric current flow, offering high resistance.

An insulating material reducing electric field intensity between conductors.

The structural component of a membrane that contributes to its high resistance.

The constant used in gas equations, measured in joules per kelvin per mole.

The electrical potential difference across a cell's membrane, influenced by ion concentrations.

A mathematical formula used to calculate membrane potential based on ion concentrations and permeabilities.

A stimulus originating from outside the body, like touch and sound.

A stimulus that comes from within the body, like hunger or thirst.

A rapid rise and fall in voltage across a cellular membrane used for nerve signal transmission.

The membrane potential level that must be reached for an action potential to occur, usually around -55mV.

A change in membrane potential that is proportional to the strength of the stimulus, not propagated far.

The membrane allows varying ion passage; K+ easily, Na+ less, Cl- freely.

Essential for potential: charged ions, concentration gradient, membrane permeability.

Ion concentration varies: K+ high inside, Na+ and Cl- high outside neurons.

Ion channels that remain open in resting neurons, allowing ion flow.

Ion channels mainly allowing K+ to pass, important for membrane potential.

Voltage across membrane due to ion distribution; state of polarization before action potential.

Transports 3 Na+ out, 2 K+ in, contributing to membrane potential and polarization.

State where K+ movement out is balanced by movement in, leading to stable membrane potential.

When K+ leaves the cell, it creates a charge imbalance which leads to equilibrium when electrical and chemical forces balance.

The difference in charge between inside and outside of the cell due to K+ movement creates an electrical force opposing further K+ exit.

Electrical force drives K+ back into the cell while chemical force drives it out, leading to equilibrium.

The membrane potential when there is no net movement of K+, as equal amounts enter and leave the cell.

The positive membrane potential that balances Na+ concentration gradient, driving membrane potential positive.

Membrane protein that pumps three Na+ out and two K+ in, maintaining ion concentration gradients.

The phase where sodium ions enter the cell, causing a rise in membrane potential, reaching +40 mV.

The phase where potassium ions exit the cell, returning the membrane potential toward resting state.

The stable membrane potential of a nerve fiber, approximately -90 mV.

The time period when no new action potential can be initiated, from firing level to 2/3 repolarization.

The period during which a new action potential can occur, but only with a stronger stimulus.

The critical level of depolarization needed to initiate an action potential.