Cell Signaling & Receptors — Cellular & General Physiology

Cell Signaling & Receptors MCQs: practice questions

Sample Cell Signaling & Receptors multiple-choice questions from Cellular & General Physiology.

1. Nitric oxide is unusual as a neurotransmitter because it:

   • A. Is a permeant gas that diffuses to its target cell
   • B. Is stored only in synaptic vesicles
   • C. Acts only through ligand-gated channels
   • D. Cannot cross membranes
   • E. Requires Na+–K+ ATPase for diffusion

2. A metabotropic glutamate receptor differs from an ionotropic glutamate receptor because it:

   • A. Is located only in muscle
   • B. Is always a chloride channel
   • C. Directly pumps Na+ using ATP
   • D. Cannot bind glutamate
   • E. Is coupled to ion channels through a heterotrimeric G protein

3. When acetylcholine binds the nicotinic receptor at the neuromuscular junction, the receptor becomes permeable mainly to:

   • A. H+ only
   • B. Ca2+ only
   • C. Cl− only
   • D. Na+ and K+
   • E. Glucose and Na+

4. A receptor coupled to Gi is activated. Which effect is expected?

   • A. Increased adenylate cyclase activity
   • B. Decreased adenylate cyclase activity
   • C. Direct activation of DNA replication
   • D. Opening of every ion channel
   • E. Increased extracellular Na+

5. NO can participate in signal transduction by activating:

   • A. GABAA receptor
   • B. Na+–K+ ATPase
   • C. Na+–glucose cotransporter
   • D. Guanylyl cyclase
   • E. Voltage-gated K+ channels directly

6. Which neurotransmitter is formed from tryptophan and can be converted to melatonin in the pineal gland?

7. Two excitatory inputs arrive simultaneously at different synapses on the same neuron and their effects add. This is:

8. The nicotinic acetylcholine receptor at the motor end plate is:

9. Two excitatory inputs arrive rapidly one after another at the same synapse and their effects add. This is:

10. A receptor activates phospholipase C through a Gq protein. Which second messengers are generated from membrane phospholipids?

11. Binding of acetylcholine to the nicotinic receptor produces a motor end-plate potential primarily by:

12. A ligand-gated ion channel is best defined as a channel that opens in response to:

13. Which neurotransmitter is primarily inhibitory and is synthesized from glutamate?

14. Which glutamate receptor is an ionotropic, ligand-gated receptor?

15. A neurotransmitter causes hyperpolarization of a postsynaptic membrane. It is best classified functionally as:

16. Activation of GABAB receptors increases:

17. Activation of GABAA receptors increases:

18. Which receptor subtype is the site of action of benzodiazepines and barbiturates?

19. Which receptor class can directly alter gene transcription after binding its ligand?

20. A receptor coupled to Gs is activated. Which intracellular change is most likely?

21. Nitric oxide synthase converts arginine to:

22. D1 dopamine receptors are coupled to adenylate cyclase through:

23. Dopamine released from the hypothalamus acts physiologically as a:

24. Histamine in neurons is formed from:

25. A patient has increased D2 receptor activity in a dopaminergic pathway. Which intracellular change is expected from the receptor mechanism described?

26. D2 dopamine receptors affect adenylate cyclase by coupling to:

27. A drug enhances GABAA receptor activity. Which immediate membrane effect is most consistent with the source?

28. Which neurotransmitter is described as the most prevalent excitatory neurotransmitter in the brain?

29. An excitatory postsynaptic potential (EPSP) generally:

30. A lipid-soluble hormone crosses the plasma membrane before binding its receptor. This is most consistent with a: