Problem Set Chapter 15

  1. Which of the following is NOT an example of a second messenger molecule in signal transduction pathways?
  1. cAMP
  2. Growth Factor
  3. Ca2+
  4. lipid cleavage products
  1. Acetylcholine is to phopholipase C in a smooth muscle cell as epinephrine is to ______in a liver cell.
  1. protein kinase C
  2. cAMP
  3. adenylyl cyclase
  4. GTP
  1. Which mutant form of Ras is likely to cause a cell to become cancerous (uncontrolled cell division)?
  1. a mutation that prevents it from binding GTP
  2. a mutation that prevents it from interacting with the Sos GEF protein.
  3. a mutation that destroys its GTPase activity
  4. a mutation that prevents it from activating the MAP kinase cascade
  1. Epinephrine binds to adrenergic receptors in liver, smooth muscle, and cardiac muscle. In liver epinephrine induces glycogen breakdown, in smooth muscle it leads to muscle relaxation, and in cardiac muscle it leads to muscle contraction. Which of the following does NOT account for different responses to epinephrine in each of these cell types:
  1. each cell type has a different adrenergic receptor
  2. different heterotrimeric G proteins are activated in each cell type
  3. adenylyl cyclase is activated in some cells and inactivated in others.
  4. an enzyme that is activated in all three cell types is capable of catalyzing glycogen breakdown, smooth muscle relaxation, and cardiac muscle contraction.
  1. Beta blocker drugs reduce blood pressure by acting as a ______to epinephrine induction of the 1 adrenergic receptor of cardiac muscle.
  1. agonist
  2. antagonist
  3. second messenger
  4. more than one of the above
  1. Proteins with SH2 domains are to ______in Growth Factor signaling pathways as heterotrimeric G proteins are to G-Protein Couple Receptors in G protein signaling pathways.
  1. Ras
  2. Receptor Tyrosine Kinases
  3. MAP kinases
  4. G proteins
  1. If you break up liver cells and separate the plasma membranes from the cell cytoplasm and then add epinephrine to the soluble cytoplasmic protein fraction, which of the following will occur:
  1. cAMP will be produced
  2. epinephrine will bind the G-protein coupled adrenergic receptor
  3. adenylyl cyclase will be activated
  4. nothing
  1. Which of the following mutations in a Receptor Tyrosine Kinase of a cell that binds a specific Growth Factor will cause the cell to divide constitutively:
  1. mutation of its phosphorylatable Tyrosine to Serine
  2. mutation of its phosphorylatable Tyrosine to Glutamic Acid
  3. mutation of its phosphorylatable Tyrosine to Glycine
  4. mutation of its phosphorylatable Tyrosine to Alanine
  1. Which of the following mutations in a Receptor Tyrosine Kinase of a cell that binds a specific growth factor will prevent the cell from dividing in response to growth factor: (Multiple correct answers)
  1. mutation of its phosphorylatable Tyrosine to Serine
  2. mutation of its phosphorylatable Tyrosine to Glutamic Acid
  3. mutation of its phosphorylatable Tyrosine to Glycine
  4. mutation of its phosphorylatable Tyrosine to Alanine
  1. DAG and IP3 are to ______as cAMP is to epinephrine.
  1. insulin
  2. acetylcholine
  3. growth factors
  4. glucagons
  1. Define each of the following terms used to describe players in signal transduction pathways:

First Messenger (ligand):

Transducer (receptor):

Adapter:

Effector:

Second Messenger:

Target:

12. For each of the following cellular responses, identify the first messenger (ligand), transducer (receptor), adapter, effector, second messenger (if there is one), ultimate targets of the signal transduction pathway:

  1. EXAMPLE: Epinephrine-stimulated glycogen breakdown in liver

first messenger: epinephrine

transducer (receptor): G protein coupled receptor (GPCR)

adapter: heterotrimeric G protein complex

effector: Adenylyl Cyclase

second messenger: cAMP

target: Glycogen phosphorylase which catalyzes the rate limiting step in glycogen breakdown

  1. Acetylcholine stimulation of stomach smooth muscle contraction

first messenger:

transducer (receptor):

adapter

effector:

second messenger:

target:

c. Growth factor stimulation of cell growth

first messenger:

transducer (receptor):

adapter

effector:

second messenger:

target:

  1. Acetylcholine stimulation of vascular smooth muscle relaxation

first messenger:

transducer (receptor):

adapter

effector:

second messenger:

target:

e. Insulin-induced uptake of glucose and glycogen synthesis

first messenger:

transducer (receptor):

adapter

effector:

second messenger:

target:

f. Receptor mediated cell death

first messenger:

transducer (receptor):

adapter

effector:

second messenger:

target:

g. Cellular damage mediated cell death

first messenger:

transducer (receptor):

adapter

effector:

second messenger:

target: