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Introduction to Cell Signaling quiz #2

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  • What is a fundamental statement of cell theory?

    All living organisms are composed of one or more cells, and the cell is the basic unit of life.
  • What is cell specialization?

    Cell specialization refers to the process by which generic cells change into specific cells meant to do certain tasks within the body.
  • Which of these is responsible for initiating a signal transduction pathway?

    A ligand, which is a signaling molecule, is responsible for initiating a signal transduction pathway by binding to a receptor.
  • What does it mean to say that a signal is transduced?

    Transduction refers to the conversion of a signal from one form to another, typically involving a series of molecular interactions that lead to a cellular response.
  • What theory is the unifying foundation of cell biology?

    B) Cell Theory
  • Which molecule triggers apoptosis?

    Caspases are a family of protease enzymes that play essential roles in apoptosis.
  • What role do phosphatases play in signal transduction pathways?

    Phosphatases remove phosphate groups from proteins, which can deactivate or activate certain signaling pathways.
  • What does quorum sensing allow bacterial cells to determine?

    A) Population density
  • What are the main points of the cell theory?

    The main points of the cell theory are: all living organisms are composed of one or more cells, the cell is the basic unit of life, and all cells arise from pre-existing cells.
  • What is the main function of eicosanoids?

    Eicosanoids are signaling molecules that play roles in inflammation, immunity, and as messengers in the central nervous system.
  • What is paracrine signaling?

    Paracrine signaling is a form of cell signaling where the target cell is close to the signal-releasing cell, allowing the signaling molecules to affect nearby cells.
  • Which of these is the second of the three stages of cell signaling?

    The second stage of cell signaling is transduction.
  • What is autocrine signaling?

    Autocrine signaling is a form of cell signaling where a cell secretes a hormone or chemical messenger that binds to receptors on its own surface, affecting the cell that produced it.
  • What is the role of the protein kinases in a cell?

    Protein kinases are enzymes that modify other proteins by chemically adding phosphate groups, which can activate or deactivate the target proteins.
  • What is the function of receptor tyrosine kinases?

    Receptor tyrosine kinases are cell surface receptors that, upon binding with a ligand, activate their intrinsic kinase activity, leading to phosphorylation of tyrosine residues on certain proteins, which triggers a signal transduction pathway.
  • What is apoptosis? What is its purpose?

    Apoptosis is a form of programmed cell death that is essential for removing unwanted or damaged cells, maintaining homeostasis, and preventing cancer.
  • Which of these is a receptor tyrosine kinase?

    The Epidermal Growth Factor Receptor (EGFR) is an example of a receptor tyrosine kinase.
  • Which molecule is involved in circadian rhythms?

    A) Melatonin
  • Which individual did not contribute to the establishment of cell theory?

    D) Louis Pasteur
  • What is the difference between intracellular signaling and intercellular signaling?

    Intracellular signaling occurs within a cell, while intercellular signaling involves communication between different cells.
  • Which concept is not part of the cell theory?

    Cells can arise spontaneously
  • How can plants and animals affect neighboring cells directly?

    Plants and animals can affect neighboring cells directly through paracrine signaling, where signaling molecules are released and affect nearby target cells.
  • Where are cell surface receptors found?

    Cell surface receptors are found embedded in the plasma membrane of cells.
  • Which of the answer choices is a cellular response to signal transduction? A) Gene expression B) Cell division C) Apoptosis D) All of the above

    D) All of the above
  • Which is a core principle of cell theory?

    A core principle of cell theory is that all living organisms are composed of one or more cells.
  • Which feature is not associated with apoptosis?

    Inflammation
  • Growth factor receptors are typically found where in the cell?

    Growth factor receptors are typically found on the cell surface, embedded in the plasma membrane.
  • How does the ras protein transmit a signal from outside the cell into the cytoplasm?

    The ras protein transmits a signal by acting as a molecular switch that, when activated by a receptor, initiates a cascade of downstream signaling events within the cytoplasm.
  • In autocrine signaling, which cells are the target cells?

    The signaling cell itself
  • Which type of cell signaling molecule crosses the cell membrane the easiest?

    Steroid hormones
  • What is molecular mimicry?

    Molecular mimicry is when a molecule, such as a pathogen, mimics the structure of a host molecule to evade the immune system or to interfere with normal cellular processes.
  • Which is true of the GTP-binding proteins that participate in intracellular signaling?

    GTP-binding proteins, such as G-proteins, act as molecular switches in signaling pathways, becoming active when bound to GTP and inactive when bound to GDP.
  • What does transduction explain in cell signaling?

    Signal conversion
  • When does apoptosis occur?

    Apoptosis occurs during development, in response to cellular damage, or to maintain homeostasis by removing unnecessary or harmful cells.
  • According to modern cell theory, what is the basic unit of life?

    According to modern cell theory, the cell is the basic unit of life.
  • What is cell signaling and why is it important for cells?

    Cell signaling is the process by which cells produce, receive, and respond to external signals, enabling communication with other cells and coordination of cellular activities.
  • What is a ligand in the context of cell signaling?

    A ligand is a small signaling molecule that binds to a specific receptor to initiate a cellular response.
  • What happens when a ligand binds to its receptor?

    When a ligand binds to its receptor, the receptor changes shape (conformational change), which initiates a series of events leading to a cellular response.