Cell Signalling and Cellular Responsiveness Overview
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Questions and Answers

What are the main types of local signals discussed in the text?

  • Paracrine Signalling and Synaptic Signalling (correct)
  • Endocrine Signalling and Neurotransmitter Signalling
  • Autocrine Signalling and Hormonal Signalling
  • Chemical Signalling and Electrical Signalling

    • Which type of signalling involves neurotransmitters like acetylcholine zipping across synapses?

  • Synaptic Signalling (correct)
  • Autocrine Signalling
  • Paracrine Signalling
  • Endocrine Signalling

    • What is the purpose of negative feedback loops in cell communication?

  • To adjust cellular actions based on external signals
  • To keep the performance in balance (correct)
  • To amplify responses
  • To coordinate defence mechanisms

    • Which cells form protective barriers according to the text?

    <p>Epithelial cells</p> Signup and view all the answers

    When considering cellular responsiveness, how do cells respond?

    <p>Both individually and as part of a larger ensemble</p> Signup and view all the answers

    What are some examples of chemical signals mentioned in the text?

    <p>Neurotransmitters, hormones, and growth factors</p> Signup and view all the answers

    How do stem cells behave in the cellular orchestra described?

    <p>Await cues for differentiation</p> Signup and view all the answers

    What is the purpose of positive feedback loops in cell communication?

    <p>To amplify responses</p> Signup and view all the answers

    What is the function of G-protein-coupled receptors (GPCRs) mentioned in the text?

    <p>Serving functions related to development and sensory reception</p> Signup and view all the answers

    During the resting state of GPCRs, what is the state of the G protein?

    <p>Bound to GDP</p> Signup and view all the answers

    What happens during the activation phase of GPCRs?

    <p>The enzyme becomes active</p> Signup and view all the answers

    Which molecule displaces GDP from the G protein during ligand binding?

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

    What initiates cellular responses in the GPCR pathway?

    <p>GTPase activity of the G protein</p> Signup and view all the answers

    Which part of the GPCR pathway determines the function through shape alterations?

    <p>Conformational Changes</p> Signup and view all the answers

    How are GPCRs related to modern drugs according to the text?

    <p>Associated with one-third of modern drugs</p> Signup and view all the answers

    What is the significance of GPCRs being associated with many diseases?

    <p>They play a crucial role in cellular signaling</p> Signup and view all the answers

    What is the role of activated proteins in the cell?

    <p>Collaborate to make things happen within the cell</p> Signup and view all the answers

    What ensures signal transmission precision and localization in the human body?

    <p>Exquisite control and specific receptors</p> Signup and view all the answers

    How does the 3D molecular shape of proteins contribute to specificity in signal transmission?

    <p>Acts as a lock for specific ligands</p> Signup and view all the answers

    Where are water-soluble molecules receptors located?

    <p>Membrane-bound</p> Signup and view all the answers

    What is the purpose of G Protein-coupled receptors (GPCRs) and ligand-gated ion channel receptors?

    <p>Control signal transduction pathways</p> Signup and view all the answers

    Why do only target receptors interact with specific signals in the body?

    <p>To activate specific cells at specific times</p> Signup and view all the answers

    How do activated proteins affect cellular processes within the cell?

    <p>Activate or inhibit enzymes, change gene expression, and kickstart cellular processes</p> Signup and view all the answers

    What distinguishes membrane-bound receptors from non-membrane-bound receptors?

    <p>Their presence on the cytoplasmic membrane</p> Signup and view all the answers

    What is the main function of protein kinases in signal transduction?

    <p>Activate target proteins through phosphorylation</p> Signup and view all the answers

    In a phosphorylation cascade, what role is played by the protein kinases?

    <p>Pass a baton to the next kinase</p> Signup and view all the answers

    What can happen if mutations affect the critical serine or threonine residues in proteins?

    <p>Lead to detrimental consequences</p> Signup and view all the answers

    What is the primary role of phosphatases in signal transduction?

    <p>Remove phosphate groups from proteins</p> Signup and view all the answers

    How does adenylyl cyclase get activated in GPCR signaling?

    <p>Stimulated by the Gα subunit of the activated G protein</p> Signup and view all the answers

    What is the consequence of activating adenylyl cyclase?

    <p>Production of cAMP</p> Signup and view all the answers

    Which residues within proteins are typically phosphorylated during signal transduction?

    <p><em>Serine</em> or <em>threonine</em> residues</p> Signup and view all the answers

    What is the primary function of adenylyl cyclase?

    <p>Convert ATP into cAMP</p> Signup and view all the answers

    How does cholera toxin disrupt the signaling pathway involving adenylyl cyclase?

    <p>Permanently activates adenylyl cyclase</p> Signup and view all the answers

    Besides cAMP, which other small molecules participate in cellular signaling cascades?

    <p>Calcium ions</p> Signup and view all the answers

    What is the typical intracellular concentration of calcium ions?

    <p>100 nanomolar (nM)</p> Signup and view all the answers

    Which organelle serves as an intracellular calcium reservoir?

    <p>Endoplasmic Reticulum (ER)</p> Signup and view all the answers

    What is the crucial role of calcium pumps in cellular function?

    <p>Transporting calcium out of the cell</p> Signup and view all the answers

    How does PKA influence cellular processes?

    <p>Phosphorylating proteins</p> Signup and view all the answers

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