BCSE Pharmacology and Toxicology 4

Question 1

Fluoroquinolones exert their bactericidal effect by inhibiting which bacterial enzyme?

Accepted Answer

DNA gyrase (topoisomerase II) and topoisomerase IV

Answer

Fluoroquinolones inhibit bacterial DNA gyrase and topoisomerase IV, enzymes necessary for DNA supercoiling and decatenation, halting DNA replication and causing bacterial cell death.

Question 2

A patient on chemotherapy develops peripheral neuropathy and the Vinca alkaloid vincristine is suspected. What is the mechanism of this toxicity?

Accepted Answer

Binding beta-tubulin and inhibiting microtubule polymerization

Answer

Vincristine binds beta-tubulin dimers and prevents microtubule assembly, disrupting axonal transport in peripheral neurons, which leads to sensorimotor neuropathy.

Question 3

Which first-line drug for type 2 diabetes primarily reduces hepatic glucose production?

Accepted Answer

Metformin

Answer

Metformin activates AMP-activated protein kinase (AMPK), suppressing hepatic gluconeogenesis and glycogenolysis, thereby reducing fasting plasma glucose without causing hypoglycemia.

Question 4

Lead poisoning in children is most associated with which neurological sequela?

Accepted Answer

Cognitive impairment and reduced IQ

Answer

Chronic low-level lead exposure in children disrupts synaptic development and calcium-mediated neurotransmitter release, causing irreversible cognitive deficits and reduced IQ.

Question 5

Which antiepileptic drug acts primarily by prolonging sodium channel inactivation?

Accepted Answer

Phenytoin

Answer

Phenytoin stabilizes the inactive state of voltage-gated sodium channels, reducing repetitive high-frequency neuronal firing without affecting normal baseline neuronal activity.

BCSE - Basic and Clinical Sciences Examination Practice Test

BCSE - Basic and Clinical Sciences Examination Practice Test

BCSE Pharmacology and Toxicology 4