Cellular Communication Mechanisms Quiz
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Questions and Answers

What is the role of potassium in determining the resting membrane potential?

  • It is not involved in establishing the resting membrane potential.
  • It plays a significant role in maintaining the resting membrane potential. (correct)
  • It has a negligible effect on the resting membrane potential.
  • It contributes equally with calcium to the resting membrane potential.
  • Why is the resting membrane potential closest to the equilibrium potential for potassium (EK = -90 mV)?

  • Potassium leak channels allow potassium efflux at rest. (correct)
  • Potassium has the highest concentration inside the cell.
  • The cell membrane is impermeable to potassium.
  • Potassium has a high equilibrium potential compared to other ions.
  • Which ions have equilibrium potentials far from the resting membrane potential?

  • Potassium and chloride
  • Sodium and calcium (correct)
  • Sodium and potassium
  • Calcium and chloride
  • What does the Goldman-Hodgkin-Katz (GHK) equation determine?

    <p>The membrane permeability to specific ions</p> Signup and view all the answers

    Which cells have a resting membrane potential of around -70 mV?

    <p>Sensory neurons</p> Signup and view all the answers

    How do sodium leak channels affect the resting membrane potential?

    <p>They allow a small influx of sodium ions, helping maintain RMP.</p> Signup and view all the answers

    What are the ions relevant for understanding the cell's electrical properties and action potential?

    <p>K+, Na+, Ca2+, Cl–</p> Signup and view all the answers

    What do ions need in order to move across the cell membrane?

    <p>Pathways provided by ion channels</p> Signup and view all the answers

    What determines the net flux of an ion through the membrane, as per the text?

    <p>Concentration gradient, membrane potential, ion membrane conductance</p> Signup and view all the answers

    In Ohm's law equation (IX = gX(Vm - EX)), what does (Vm - EX) represent?

    <p>Driving force for the movement of ion X+</p> Signup and view all the answers

    What happens when there is an inward current across the cell membrane?

    <p>There is an influx of positive charges</p> Signup and view all the answers

    What is the role of gX in determining the net flux of an ion according to Ohm's law?

    <p>Membrane conductance specific for X+</p> Signup and view all the answers

    What determines the receptor a ligand binds to?

    <p>Chemical nature of the ligand</p> Signup and view all the answers

    How do ligands affect receptor affinity for inhibitory proteins?

    <p>Decrease receptor affinity</p> Signup and view all the answers

    Intracellular receptors modify cell behavior through changes in:

    <p>Gene expression</p> Signup and view all the answers

    Which subunit of G proteins determines receptor coupling to signaling modules?

    <p>Alpha subunit</p> Signup and view all the answers

    What type of signaling involves the activation of membrane-bound adenylyl cyclases and synthesis of cAMP?

    <p>Gs-coupled signaling pathway</p> Signup and view all the answers

    Which ligand-binding modulates signal transduction pathways?

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

    Which type of communication allows the transfer of small molecules and electrical signals from cell to cell?

    <p>Gap junctions</p> Signup and view all the answers

    What defines autocrine signaling?

    <p>Chemical signal acts on the same cell that released it</p> Signup and view all the answers

    Which mode of cell communication uses hormones released into the blood to act on specific receptors in the body?

    <p>Endocrine system</p> Signup and view all the answers

    What plays an important role in the conduction of action potentials of cardiac muscle?

    <p>Gap junctions</p> Signup and view all the answers

    Which signaling occurs when a chemical signal is released and acts on neighboring cells near the site of release?

    <p>Paracrine signaling</p> Signup and view all the answers

    Which term describes the situation where all binding sites for a specific ligand have been occupied?

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

    In what way does the nervous system communicate with cells and specific cell receptors?

    <p>Using both chemical signals and electrical signals</p> Signup and view all the answers

    What type of ligands bind to the receptor and prevent any response from occurring?

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

    What occurs when a high concentration of a signaling molecule results in a decrease in the number of receptors in the membrane?

    <p>Down-regulation</p> Signup and view all the answers

    Which process involves a chemical modulator binding to a receptor, blocking its activation by the ligand?

    <p>Receptor desensitization</p> Signup and view all the answers

    What is the term used for ligands that bind to and activate receptors, causing a response?

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

    In what situation does up-regulation of receptors typically occur?

    <p>Low ligand levels</p> Signup and view all the answers

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