A

Na+

N

ICF Ca2+ concentration

B

K+

O

Na+ permeability

C

Cl-

P

K+ permeability

D

Ca2+

Q

Cl- permeability

E

Extracellular fluid (ECF)

R

Ca2+ permeability

F

Intracellular fluid (ICF)

S

Voltage-gated Na+ channels

G

ECF Na+ concentration

T

Voltage-gated K+ channels

H

ICF Na+ concentration

U

L-type Ca2+ channels

I

ECF K+ concentration

V

T-type Ca2+ channels

J

ICF K+ concentration

W

Na+ leak channels

K

ECF Cl- concentration

X

K+ leak channels

L

ICF Cl- concentration

Y

Cl- leak channels

M

ECF Ca2+ concentration

Z

Na+/K+ ATPase

Select the one most appropriate answer (enter A to Z) from the options above.

Adding additional [ Select ] across the neuronal membrane would make resting membrane potential more negative than -70mV?.

Question

A

Na+

N

ICF Ca2+ concentration

B

K+

O

Na+ permeability

C

Cl-

P

K+ permeability

D

Ca2+

Q

Cl- permeability

E

Extracellular fluid (ECF)

R

Ca2+ permeability

F

Intracellular fluid (ICF)

S

Voltage-gated Na+ channels

G

ECF Na+ concentration

T

Voltage-gated K+ channels

H

ICF Na+ concentration

U

L-type Ca2+ channels

I

ECF K+ concentration

V

T-type Ca2+ channels

J

ICF K+ concentration

W

Na+ leak channels

K

ECF Cl- concentration

X

K+ leak channels

L

ICF Cl- concentration

Y

Cl- leak channels

M

ECF Ca2+ concentration

Z

Na+/K+ ATPase

Select the one most appropriate answer (enter A to Z) from the options above.

Adding additional [ Select ] across the neuronal membrane would make resting membrane potential more negative than -70mV?.

BlackTom AI · Accepted Answer

Resting potential is dominated by K+ conductance, so increasing K+ leak conductance will make the membrane more negative (hyperpolarize) — answer X (K+ leak channels).

1) Relevant concepts
- Nernst potential for an ion: E = (61.5 mV) log10([out]/[in]) at 37°C. E_K is strongly negative because intracellular K+ is high; E_Na is strongly positive because extracellular Na+ is high.
- Goldman equation: Vm depends on relative permeabilities (P) and concentrations of major ions (primarily K+, Na+, Cl−). Increasing permeability to an ion moves Vm toward that ion’s Nernst potential.
- Leak channels set the baseline permeabilities that determine resting membrane potential (RMP).

2) Step-by-step reasoning
- Compute typical Nernst values (37°C):
  - E_K ≈ 61.5·log10([K+]out/[K+]in). With [K+]out ≈ 4 mM, [K+]in ≈ 140 mM:
    E_K ≈ 61.5·log10(4/140) = 61.5·log10(0.0286) ≈ 61.5·(−1.544) ≈ −95 mV.
  - E_Na ≈ 61.5·log10(145/12) ≈ 61.5·1.082 ≈ +67 mV.
- Typical RMP ≈ −65 to −75 mV because P_K » P_Na; Vm lies between E_K and E_Na but closer to E_K.
- If additional K+ leak channels are added, P_K increases. By the Goldman principle, Vm shifts closer to E_K (≈ −95 mV), i.e., becomes more negative than −70 mV (hyperpolarization).

3) Why X is correct
- K+ leak channels directly increase K+ permeability, pulling Vm toward the negative E_K and making RMP more negative.

4) Why other choices are incorrect (brief)
- More Na+ leak channels would depolarize (move Vm toward +67 mV).
- Increasing Cl− permeability usually clamps Vm near E_Cl (often near RMP) and does not reliably hyperpolarize beyond −70 mV.
- Opening voltage-gated channels (Na+, K+, Ca2+ types) or L/T-type Ca2+ channels affects excitability but are not the primary determinants of a more negative steady RMP in the same way as increasing K+ leak.
- The Na+/K+ ATPase maintains gradients and can cause a small hyperpolarizing current, but adding leak K+ channels produces the direct, larger shift toward the negative E_K.

Conclusion: Increasing K+ leak channels (X) will make the resting membrane potential more negative than −70 mV, matching the provided answer X.

类似问题

A group of neurons expresses a pump which actively transports Vz2- into the cell, and also expresses a limited number of Vz2- leak channels in the cell membrane. How would resting membrane potential change in this scenario compared to a “standard” neuron?

Which of the following statements concerning the neuronal membrane at rest is correct?

The resting potential of a neuron is negative because _____________.

Which ONE of the following factors DOES NOT contribute significantly to the resting membrane potential?

If Na+/K+ ATP-ase were inhibited in a resting neuron, which voltage would the neuron ultimately reach over a long period of time?

Increasing the expression of which membrane protein in a resting neuron would bring RMP closer to threshold voltage?

Which ONE of the following statements about the resting membrane potential of a neuron is NOT CORRECT?

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