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Molecular Signaling within Neurons

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1. Which type of chemical signaling acts over a small neural region encompassing a cluster of nerve cells? a. Endocrine b. Exocrine c. Paracrine d. Synaptic e. Ephaptic Answer: c Textbook Ref... erence: Strategies of Molecular Signaling Bloom’s Level: 1. Remembering 2. In a signal transduction cascade using G-proteins and cAMP, which is not a signal amplification step? a. Activation of G-proteins by an activated receptor b. Activation of adenylyl cyclase molecules by G-proteins c. Creation of cAMP molecules by adenylyl cyclase d. Phosphorylation of target proteins by protein kinase A e. All of the above are steps in which amplification occurs Answer: b Textbook Reference: Strategies of Molecular Signaling Bloom’s Level: 2. Understanding 3. Which statement about cell signaling pathways is true? a. Cellular responses are always short-lived. b. Cellular responses are always long-lived. c. Signaling is always initiated by membrane-bound receptors. d. Signaling is always initiated by intracellular receptors. e. Intracellular signal transduction pathways are always activated by a chemical signaling molecule. Answer: e Textbook Reference: Activation of Signaling Pathways Bloom’s Level: 2. Understanding 4. The acetylcholine receptor at the neuromuscular junction would best be described as a(n) a. channel-linked receptor. b. enzyme-linked receptor. c. G-protein-coupled receptor. d. nuclear receptor. e. gap junction. Answer: a Textbook Reference: Receptor Types Bloom’s Level: 1. Remembering 5. Cholera toxin locks the Gs subunit into an active state, in that GTP is bound and cannot be hydrolyzed back to GDP to turn off the subunit. What effect will cholera toxin have in the cell? a. The Gs subunit will more strongly inhibit adenylyl cyclase. b. Inhibited adenylyl cyclase will lead to increased cyclic AMP levels. c. Activated adenylyl cyclase will lead to decreased cyclic AMP levels. d. Increased cyclic AMP levels will lead to increased protein kinase A activation. e. Decreased cyclic AMP levels will lead to decreased protein kinase A activation. Answer: d Textbook Reference: G-proteins and Their Molecular Targets Bloom’s Level: 4. Analyzing 6. In the marine mollusk, Aplysia, serotonin binds to a G-protein-coupled receptor and activates a Gs subunit. The resulting activation of PKA leads to phosphorylation and closure of K+ channels. What effect would this have on the cell? a. Decreased K+ efflux depolarizing the cell b. Increased K+ efflux hyperpolarizing the cell c. Decreased K+ efflux hyperpolarizing the cell d. Increased K+ efflux depolarizing the cell e. No change in K+ ion flow or membrane potential Answer: a Textbook Reference: G-proteins and Their Molecular Targets Bloom’s Level: 3. Applying 7. Stimulation of metabotropic receptors cannot a. open ion pores in the G-protein structure. b. cause G-proteins to alter ion channels. c. cause G-proteins to start second messenger cascades. d. lead to widespread protein phosphorylation. e. lead to gene transcription. Answer: a Textbook Reference: Second Messengers Bloom’s Level: 2. Understanding 8. Which of the following does not contribute to maintaining low levels of calcium in resting nerve cells? a. Voltage-gated calcium channels b. The plasma membrane calcium ATPase c. The smooth endoplasmic reticulum calcium ATPas [Show More]

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