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Home Biochemistry Cell Signalling and Transduction Comments

  • Question
  • The hormone or ligand can be considered as


  • Options
  • A. first messenger
  • B. second messenger
  • C. both (a) and (b)
  • D. none of these

  • Correct Answer
  • first messenger 


  • Cell Signalling and Transduction problems


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    • 1. Which of the following is a second messenger?

    • Options
    • A. lnositol 1,4,5-triphosphate
    • B. Diacyl glycerol
    • C. Phospholipase C
    • D. Both (a) and (b)
    • Discuss
    • 2. SH2 domains specifically bind to

    • Options
    • A. phosphorylated serine residues
    • B. phosphorylated tyrosine residues
    • C. GDP
    • D. Ca2+
    • Discuss
    • 3. Why is it that inhaling nitric oxide reduces blood pressure only in the lung tissue and not elsewhere in the body*?

    • Options
    • A. Because other body tissues use a different signaling molecule
    • B. Because nitric oxide cannot cross cell membranes and enter the blood
    • C. Because nitric oxide breaks down quickly and thus cannot travel far
    • D. None of the above
    • Discuss
    • 4. Which of the following is true about a hydrophilic signaling molecule?

    • Options
    • A. Its receptor is located in the cytosol of the target cell
    • B. It might trigger a signal cascade that causes some effect in a cell
    • C. Since it can enter the cell, it directly affects some specific cell process
    • D. It is a steroid
    • Discuss
    • 5. If a disease of the blood vessels caused the endothelial cells of the vessel to die, what effect would that have on the cellular activities associated with vasodilation?

    • Options
    • A. Nitric oxide would no longer be produced
    • B. Smooth muscle cells could not be made to relax
    • C. It would be more difficult to increase blood flow and reduce blood pressure
    • D. All of the above
    • Discuss
    • 6. Cell signaling can be classified into

    • Options
    • A. three distinct types based on the distance over which the signaling molecules act
    • B. two distinct types based on the distance over which the signaling molecules act
    • C. three distinct types based on the signaling molecules
    • D. none of the above
    • Discuss
    • 7. The major second messengers are

    • Options
    • A. cAMP
    • B. cGMP
    • C. DAG
    • D. All of these
    • Discuss
    • 8. Simple nerve reflexes use signaling molecules called

    • Options
    • A. neurotransmitters
    • B. nitric oxides
    • C. G proteins
    • D. proteases
    • Discuss
    • 9. The binding of ligands to many G-proteins linked receptors leads to shortlived

    • Options
    • A. increase in the concentration of certain intracellular signaling molecules called second messenger
    • B. decrease in the concentration of certain intracellular signaling molecules called second messenger
    • C. increase in the concentration of certain extracellular signaling molecules called first messenger
    • D. decrease in the concentration of certain extracellular signaling molecules called first messenger
    • Discuss
    • 10. The enzyme that catalyzes the splitting of PIP2 into two molecules of inositol triphosphate (IP3) and diacylglycerol in cell signaling, is

    • Options
    • A. phosphokinase C
    • B. phospholipase C
    • C. phosphodiesterase C
    • D. lipokinase
    • Discuss


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