Pharmacology Quiz
Questions: 16 · 10 minutes
1. Which action best describes the antibacterial mechanism of aminoglycosides?
Inhibition of bacterial cell-wall cross-linking by binding penicillin-binding proteins
Binding to the 30S ribosomal subunit and promoting misreading of messenger RNA
Blockade of DNA gyrase and topoisomerase IV
Inhibition of folate production through blockade of dihydropteroate synthase
2. A patient taking a nonselective beta blocker has a reduced heart rate and may also develop bronchoconstriction. Which action best explains both effects?
Blockade of muscarinic receptors in the heart and bronchial glands
Activation of alpha-1 receptors in blood vessels and beta-2 receptors in the lungs
Blockade of beta-1 receptors in the heart and beta-2 receptors in bronchial smooth muscle
Inhibition of angiotensin-converting enzyme in the lungs and circulation
3. A partial agonist is given while a full agonist is already occupying the same receptor population. What may happen?
The partial agonist must increase the response because it adds to the full agonist's effect
Both drugs lose receptor affinity while retaining full efficacy
The full agonist becomes an irreversible antagonist at the receptor
The overall response may fall because the partial agonist occupies receptors but produces less activation
4. Which signaling mechanism is initiated when insulin binds to its receptor?
Activation of intrinsic receptor tyrosine kinase activity
Opening of a ligand-gated chloride channel
Direct activation of a nuclear transcription receptor
Coupling to a Gs protein that directly raises cyclic AMP
5. Furosemide increases sodium and water excretion by blocking which transporter?
The sodium-chloride cotransporter in the distal convoluted tubule
The sodium-potassium-2 chloride cotransporter in the thick ascending limb
The epithelial sodium channel in the collecting duct
The sodium-glucose cotransporter in the proximal tubule
6. A reversible competitive antagonist is added while studying an agonist's dose-response curve. What change is most likely if enough agonist can overcome the antagonism?
A lower maximum response that cannot be restored by increasing the agonist concentration
A leftward shift of the curve with an increase in agonist potency
A rightward shift of the curve with no change in the maximum response
A response in the absence of agonist because the antagonist activates the receptor
7. An orally administered drug reaches systemic circulation at a much lower concentration than the same intravenous dose. Which process is the most direct explanation?
Extensive binding to plasma proteins after entering the circulation
Metabolism in the intestinal wall or liver before reaching systemic circulation
Rapid receptor internalization following target binding
Active renal secretion before distribution to tissues
8. A drug is eliminated at an approximately constant amount per hour when its elimination pathway is saturated. Which kinetic pattern does this illustrate?
First-order elimination, in which a constant fraction is removed per unit time
Ion trapping, in which urinary pH prevents any further clearance
Flow-limited distribution, in which tissue uptake determines elimination
Zero-order elimination, in which a constant amount is removed per unit time
9. Statins lower cholesterol synthesis by competitively inhibiting which enzyme?
HMG-CoA reductase
Acyl-CoA cholesterol acyltransferase
Lipoprotein lipase
Proprotein convertase subtilisin/kexin type 9
10. Warfarin reduces the production of functional clotting factors through which mechanism?
Inhibition of vitamin K epoxide reductase, reducing vitamin K recycling
Potentiation of antithrombin-mediated factor Xa inhibition
Irreversible blockade of platelet ADP receptors
Direct binding and inactivation of thrombin in circulating blood
11. Unfractionated heparin produces anticoagulation soon after administration. Which mechanism is responsible?
Direct inhibition of vitamin K epoxide reductase in the liver
Enhancement of antithrombin activity against clotting factors such as thrombin and factor Xa
Irreversible inhibition of platelet cyclooxygenase-1
Conversion of plasminogen to plasmin within an existing clot
12. Atropine can reduce salivary and respiratory secretions before a procedure. Which receptor action produces this effect?
Stimulation of alpha-2 adrenergic receptors in the brainstem
Activation of nicotinic acetylcholine receptors at autonomic ganglia
Inhibition of acetylcholinesterase at cholinergic synapses
Competitive antagonism of muscarinic acetylcholine receptors
13. Why can proton pump inhibitors such as omeprazole suppress gastric acid secretion for longer than their plasma half-life alone would suggest?
They permanently neutralize acid already present in the stomach
They remain tightly bound to circulating albumin for several days
They irreversibly inhibit active gastric hydrogen-potassium ATPase pumps
They continuously block histamine H2 receptors after leaving the bloodstream
14. A persistent dry cough develops after initiation of an ACE inhibitor. Which pharmacological effect most directly contributes to this reaction?
Accumulation of bradykinin after reduced enzymatic degradation
Blockade of beta-2 receptors in bronchial smooth muscle
Reduced histamine breakdown in mast cells
Inhibition of carbonic anhydrase in the respiratory tract
15. Naloxone can reverse opioid-induced respiratory depression primarily because it does what?
Prevents opioid absorption by binding the drug in the intestine
Accelerates opioid elimination by inducing hepatic enzymes
Activates GABA-A receptors in the respiratory center
Competitively blocks opioid receptors, including mu receptors
16. How do benzodiazepines enhance signaling at GABA-A receptors?
They inhibit the enzymatic breakdown of GABA in the synaptic cleft
They increase the duration of chloride-channel opening independently of GABA
They increase the frequency of GABA-mediated chloride-channel opening
They directly activate GABA-B receptors coupled to potassium channels