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General Biology: Cell Communication and Membrane Transport

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Terms in this set (20)

  • Why is cell communication essential in multicellular organisms?
    It coordinates activities among cells to maintain proper function and response to the environment.
  • What types of signals do cells use to communicate?
    Cells use chemical, electromagnetic, and mechanical signals.
  • What is a signal-transduction pathway?
    A process by which a signal on a cell’s surface is converted into a specific cellular response.
  • Name three types of cell signaling.
    • Paracrine signaling
    • Synaptic signaling (neurotransmitters)
    • Endocrine signaling (hormones)
  • What happens during the reception stage of cell signaling?
    A chemical signal (ligand) binds to a cellular protein, usually at the cell surface.
  • What occurs during the transduction stage of cell signaling?
    Binding activates the receptor, triggering a series of changes along a signal-transduction pathway.
  • What is the final stage of cell signaling and its outcome?
    Response: the transduced signal triggers a specific cellular activity.
  • What is a phosphorylation cascade in cell signaling?
    A series of protein activations by adding phosphate groups, acting as a rapid switch to turn proteins on or off.
  • Give an example of a ligand and its cellular response.
    Epinephrine (ligand) causes glucose release (response).
  • Why do bacteria find it difficult to survive in jam based on osmosis?
    High sugar concentration outside causes water to leave bacterial cells by osmosis, dehydrating and killing them.
  • What is diffusion?
    The movement of molecules from an area of higher concentration to an area of lower concentration.
  • What is osmosis?
    The diffusion of water across a semipermeable membrane from low to high solute concentration.
  • What is the function of the plasma membrane?
    To regulate what enters and leaves the cell and to protect the cell.
  • How do membrane proteins function?
    They assist in transport, signal reception, and maintaining cell structure.
  • How do plasma membranes adapt to cold environments?
    By increasing unsaturated fatty acids to maintain fluidity.
  • How do plasma membranes adapt to hot environments?
    By increasing saturated fatty acids to maintain membrane stability.
  • What does it mean if a dialysis bag gains mass in a sucrose solution?
    Water moved into the bag by osmosis, indicating the bag's solution is hypotonic relative to the outside.
  • What does it mean if a dialysis bag loses mass in a sucrose solution?
    Water moved out of the bag by osmosis, indicating the bag's solution is hypertonic relative to the outside.
  • What is a hypertonic solution?
    A solution with a higher solute concentration compared to another solution.
  • What is a hypotonic solution?
    A solution with a lower solute concentration compared to another solution.