Which of the following best describes the electrical state of a neuron at rest?
a. The inside of a neuron is more negatively charged than the outside.
b. The outside of a neuron is more negatively charged than the inside.
c. The inside and the outside of a neuron have the same electrical charge.
d. Potassium ions leak into a neuron at rest.
Introduction:
The electric potential is generated across the membrane by the neurons. The efficient functioning of the neurons is based on the generation of electric potential because it modifies the propagation of the signals across the cells.
Answer to Problem 1U
Correct answer:
The negative potential is maintained inside the neuron as compared to that of the outside when the neuron is at resting position. The difference between the potential between the inside and outside of a neuron is called the resting potential. Therefore, option a. is correct.
Explanation of Solution
Reason for the correct statement:
The negative potential of the inside of the cell is maintained due to the difference of the concentration of ions, such that the inside of the cell has a high level of potassium and low level of sodium. The outside of the cell has a high level of sodium and low level of potassium.
Option a. is given as “The inside of a neuron is more negatively charged than the outside”.
As, “potassium is present in high levels inside the cell, thus the inside of the cell has more negative potential that outside”, is the right answer.
Hence, option a. is correct.
Reasons for the incorrect statements:
Option b. is given as “The outside of a neuron is more negatively charged than the inside”.
The outside region of the cell is more positively charged than the inside of the cell. So, it is a wrong answer.
Option c. is given as “The inside and the outside of a neuron have the same electrical charge”.
Due to the difference between the concentrations of the ions inside and outside of neuron, they both cannot have same electrical charge. So, it is a wrong answer.
Option d. is given as “Potassium ions leak into a neuron at rest”.
There are more potassium ions inside the neuron than that of the outside of the neuron. The potassium ions will leak outside of the neuron. So, it is a wrong answer.
Hence, options b., c., and d. are incorrect.
The resting state of a neuron is defined as the state when the inside of the neuron is more negatively charged than the outside region of the neuron.
Want to see more full solutions like this?
Chapter 43 Solutions
BIOLOGY VOL. II
- Which of the following is true about the conduction of action potentials? a. Thicker axons are faster because there is more surface area on thicker axons. b. Myelin speeds conduction because the glial cells add voltage gated Na+ channels to the neuron. c. Diffusion of Na+ ions between the Nodes of Ranvier happens faster than the wave of opening and closing membrane proteins can travel. d. Neurons that don’t have myelin sheaths undergo saltatory conduction e. Action potentials move slowly.arrow_forwardWhich of the following insulates and protects a neuron’s axon, as well as helps speed along electrical impulses? a. synaptic knobs c. myelin sheath b. receptor sites d. neuromodulatorsarrow_forwardAt rest, a neuron has a lower concentration of sodium than the surrounding fluid. When a neuron sends a signal, it opens sodium channels. What happens to the sodium when the sodium channels open? O A. The sodium diffuses out of the cellI. B. The sodium is pumped into the cell. O C. The sodium is pumped out of the cell. D. The sodium diffuses into the cell. rered MacBook Air 吕口 F3 F1 F2 O00 F4 F5 F6 F7 F8 % & * 2 5 6 8 %244 2# 3arrow_forward
- What part of the membrane composition of a neuron is most important for the permeability of the membrane to various ions? Group of answer choices a. The outside and inside are charged b. There are proteins embedded in the membrane c. There is myelin around some cells d. Its ability to exist in fluid enviornmentarrow_forwardA neuron must reach threshold to fire an action potential. In this context, threshold refers to which event? a. voltage at which damage occurs to the membrane because of the electrical charge b. the voltage at which potassium ions begin to flow in and out of the cell c. the voltage at which voltage-gated sodium channels open d. the voltage at which the neuron can no longer produce an action potential According to studies in developing rodents, testosterone treatment causes detectable changes in: a. the sex region Y gene b. the thalamus c. the hypothalamus d. alpha-fetoproteinarrow_forwardWhich part of the neuron likely contains the most vesicles? a. Dendritesb. Cell bodyc. Nucleusd. Axone. Axon Terminal Which part of the neuron has the most voltage-gated calcium channels? a. Dendritesb. Cell bodyc. Nucleusd. Axone. Axon Terminalarrow_forward
- When a neuron is stimulated, sodium moves into the cell, causing the inside of the neuron to __________. a. become less negative relative to the outside b. become more negative relative to the outside c. remain neutral in charge d. become less positive relative to the outsidearrow_forwardDuring an action potential, the inside of the cell membrane becomes more positive than the outside. Why does this happen? a. During depolarization, the sodium ions rush in and the potassium ions have not begun rushing out, making the inside more positive. b. During depolarization, the sodium ions rush in and the potassium ions have not begun rushing out, making the outside more positive. c. During depolarization, the potassium ions rush in and the sodium ions have begun rushing out, making the inside more positive. d. During depolarization, the sodium ions rush in and the potassium ions have begun rushing out, making the outside more positive.arrow_forwardAt rest, a neuron has a lower concentration of sodium than the surrounding fluid. When a neuron sends a signal, it opens sodium channels. What happens to the sodium when the sodium channels open? A. The sodium diffuses out of the cell. B. The sodium is pumped into the cell. O C. The sodium is pumped out of the cell. O D. The sodium diffuses into the cell. nswered MacBook Air 20 F3 F5 @ $ % & * 2 6 7 8 W E Rarrow_forward
- When a neuron is inactive, more of which of the following exist OUTSIDE the neuron? A. Myelin sheaths B. Positive ions C. Neuropeptides D. Negative ionsarrow_forwardThe nerve impulses always travel in one direction from dendrites to axon terminals. What prevents an action potential from travelling backward? a. Hyperpolarization of the neuron makes the membrane more positive and prevents another action potential. b. After repolarization, the refractory period occurs, where the sodium ions are found outside the cell. c. After repolarization, the reversal of ions prevents another action potential as there would not be enough sodium ions outside the cell to rush in. d. The refractory period prevents another action potential by lowering the threshold potential.arrow_forwardThe presence of an electrical gradient is responsible for both the resting membrane potential and the action potential in the neuron.a. In this case who is responsible for maintaining the electric gradient to produce a potential for the resting membrane?b. Explain what is meant by an electrical gradient in the context of a cell (neuron)!arrow_forward
- Human Anatomy & Physiology (11th Edition)BiologyISBN:9780134580999Author:Elaine N. Marieb, Katja N. HoehnPublisher:PEARSONBiology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStaxAnatomy & PhysiologyBiologyISBN:9781259398629Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa StouterPublisher:Mcgraw Hill Education,
- Molecular Biology of the Cell (Sixth Edition)BiologyISBN:9780815344322Author:Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter WalterPublisher:W. W. Norton & CompanyLaboratory Manual For Human Anatomy & PhysiologyBiologyISBN:9781260159363Author:Martin, Terry R., Prentice-craver, CynthiaPublisher:McGraw-Hill Publishing Co.Inquiry Into Life (16th Edition)BiologyISBN:9781260231700Author:Sylvia S. Mader, Michael WindelspechtPublisher:McGraw Hill Education