Cell Membrane Functions and Ion Concentrations Quiz
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Questions and Answers

What is the resting potential of a neuron?

  • -50mV
  • -70mV (correct)
  • -100mV
  • -90mV

    • What is the main role of axons in our vision?

  • Compensating for movement accuracy (correct)
  • Stimulating hormone release
  • Detecting color
  • Regulating sleep patterns

    • What covers a neuron and is composed of 2 layers of phospholipid molecules?

  • Golgi Apparatus
  • Membrane (correct)
  • Endoplasmic Reticulum
  • Mitochondria

    • What provides the membrane of a neuron with a combination of flexibility and firmness?

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

    What is the role of electrical gradient (polarization) in a neuron?

    <p>Maintaining resting potential (D)</p> Signup and view all the answers

    What type of channels permit certain ions to cross through the neuron membrane at a controlled rate?

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

    What is the main reason a neuron inside the membrane has a slightly negative electrical potential with respect to the outside?

    <p>Presence of negatively charged proteins inside the cell (B)</p> Signup and view all the answers

    How is resting potential in a neuron typically measured?

    <p>By inserting a very thin microelectrode into the cell body (A)</p> Signup and view all the answers

    What is the typical level of resting potential in a neuron?

    <p>-70 millivolts (B)</p> Signup and view all the answers

    What is the most common electrode used for recording activity of a neuron?

    <p>A fine glass tube filled with a concentrated salt solution (C)</p> Signup and view all the answers

    Which chemicals pass through a neuron membrane more freely because channels for them are always open?

    <p>Oxygen, carbon dioxide, urea, and water (D)</p> Signup and view all the answers

    What are the biologically important ions that cross membrane channels sometimes open or closed?

    <p>Sodium, potassium, calcium, and chloride (A)</p> Signup and view all the answers

    What happens to the resting potential when the neuron is stimulated?

    <p>It remains stable (A)</p> Signup and view all the answers

    What is the molecular basis of action potential regarding sodium and potassium ions?

    <p>Sodium ions are mostly outside and potassium ions are mostly inside (A)</p> Signup and view all the answers

    What happens at the peak of the action potential?

    <p>Sodium channels close (C)</p> Signup and view all the answers

    What is the function of a voltage-gate channel?

    <p>Regulating the permeability of sodium and potassium based on charge (A)</p> Signup and view all the answers

    During the resting potential, what is the state of potassium channels?

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

    What does hyperpolarization refer to?

    <p>Increase in polarization (A)</p> Signup and view all the answers

    What happens to the sodium-potassium pump after an unusually rapid series of action potentials?

    <p>It accumulates sodium within the axon. (A)</p> Signup and view all the answers

    Under what conditions does excessive stimulation leading to the buildup of toxic sodium typically occur?

    <p>During a stroke or after using certain drugs. (B)</p> Signup and view all the answers

    What is the role of local anesthetic drugs like NOVOCAIN and XYLOCAIN on the sodium channels of the membrane?

    <p>Prevent sodium ions from entering. (C)</p> Signup and view all the answers

    What do action potentials require for their occurrence?

    <p>Movement of both sodium and potassium ions. (B)</p> Signup and view all the answers

    How do local anesthetic drugs like NOVOCAIN and XYLOCAIN affect the transmission of pain signals?

    <p>Prevent pain signal transmission to the brain. (D)</p> Signup and view all the answers

    What happens when a dentist administers NOVOCAIN before a dental procedure?

    <p>Axons cannot transmit pain signals to the brain. (C)</p> Signup and view all the answers

    What is the function of the sodium-potassium pump?

    <p>Transport three sodium ions out of the cell and two potassium ions into the cell (C)</p> Signup and view all the answers

    During rest, why do very few sodium ions cross the membrane?

    <p>Due to the closed sodium channels preventing sodium flow (B)</p> Signup and view all the answers

    What is the role of potassium channels during rest?

    <p>They allow slow potassium flow as they are nearly but not entirely closed (C)</p> Signup and view all the answers

    Which ions are more concentrated outside the neuron when the membrane is at rest?

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

    What happens to the electrical gradient across the membrane as potassium ions leak out slowly?

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

    Why does the selective permeability of the membrane make the Sodium Potassium Pump (SSP) effective?

    <p>To prevent leaking back of sodium ions that are pumped out of the neuron (A)</p> Signup and view all the answers

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