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Intracellular messnegers: Hormones and Nitric Oxide quiz #1 Flashcards

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Intracellular messnegers: Hormones and Nitric Oxide quiz #1
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  • Which hormone regulates the production of red blood cells?
    Red blood cell production is regulated by the hormone erythropoietin.
  • How does testosterone alter cell function at the molecular level?
    Testosterone, a steroid hormone, crosses the plasma membrane and binds to intracellular nuclear receptors. This binding triggers the receptor to move into the nucleus, where it acts as a transcriptional regulator to alter gene expression and thus change cell function.
  • What triggers the transfer of nuclear receptors from the cytosol to the nucleus?
    Binding of a hormone to the nuclear receptor triggers its transfer into the nucleus. This allows the receptor to act as a transcriptional regulator.
  • How do steroid hormones achieve specificity in gene regulation?
    Steroid hormones bind to specific nuclear receptors, which only interact with certain DNA regulatory sites. This ensures that only particular genes are regulated by each hormone-receptor pair.
  • What conformational change occurs when a hormone binds to its nuclear receptor?
    The nuclear receptor undergoes a conformational change upon hormone binding. This change activates the receptor for its role in gene regulation.
  • Where can nuclear receptors be found before hormone activation?
    Nuclear receptors can be located in the cytosol before hormone activation. They move to the nucleus only after binding their specific hormone.
  • What is the role of nitric oxide in blood vessels?
    Nitric oxide is released into blood vessels to stimulate muscle relaxation. This process helps regulate blood flow and pressure.
  • Which intracellular protein does nitric oxide bind to in the mechanism of Viagra?
    Nitric oxide binds to guanylate cyclase inside the cell. This interaction leads to the formation of cyclic GMP, which mediates Viagra's effects.
  • How does nitric oxide cross the plasma membrane?
    Nitric oxide diffuses freely across the plasma membrane without assistance. Its small size and gaseous nature allow this passive movement.
  • What is the downstream effect of cyclic GMP formed by guanylate cyclase activation?
    Cyclic GMP produced by guanylate cyclase leads to physiological effects such as those seen with Viagra. It acts as a secondary messenger in signaling pathways.