• 1. 
    Many signal transduction pathways use second messengers to:

  • transport a signal through the lipid bilayer portion of the plasma membrane.
  • relay a signal from the outside to the inside of the cell.
  • relay the message from the inside of the membrane throughout the cytoplasm.
  • amplify the message by phosphorylating proteins.
  • 2. 
    What is a G protein?

  • specific type of membrane-receptor protein
  • protein on the cytoplasmic side of a membrane
  • membrane-bound enzyme
  • relay protein
  • 3. 
    Of the following, a receptor protein in a membrane that recognizes a chemical signal is most similar to

  • the active site of an enzyme in the cytoplasm that binds to a specific substrate.
  • RNA specifying the amino acids in a polypeptide.
  • genes making up a chromosome.
  • an enzyme with an optimal pH and temperature for activity.
  • 4. 
    Which of the following can activate a protein by transferring a phosphate group to it?

  • cAMP
  • G proteins
  • phosphodiesterase
  • protein kinase
  • 5. 
    What could happen to the target cells in an animal that lack receptors for local regulators?

  • They could compensate by receiving nutrients via an α factor.
  • They could develop normally in response to neurotransmitters instead.
  • They could divide but never reach full size.
  • They would not be able to multiply in response to growth factors from nearby cells.
  • 6. 
    Which letter represents the cell surface receptor protein?

  • A
  • B
  • C
  • D
  • E
  • 7. 
    Which letter represents the cell membrane?

  • A
  • B
  • C
  • D
  • E
  • 8. 
    Which of the following is a chemical message that usually travels through the bloodstream to target cells?

  • hormone
  • local regulator
  • endocrine cell
  • 9. 
    The 3 steps of signal transduction in order are

  • reception, transduction, response
  • response, transduction, reception
  • reception, response, transduction
  • transduction, reception, response
  • 10. 
    Which letter represents the ligand?

  • A
  • B
  • C
  • D
  • E
  • 11. 
    In cell signaling, how is the flow of specific ionsregulated?

  • Opening and closing of ligand-gated channels
  • Transduction
  • Cytoskeleton rearrangement
  • Endocytosis
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