Antibiotic inhibiting bacterial RNA synthesis is:

Correct Answer: B

Rationale: The correct answer is B: Rifampin. Rifampin inhibits bacterial RNA synthesis by binding to the bacterial RNA polymerase enzyme. This prevents transcription of bacterial RNA, leading to inhibition of bacterial growth. Erythromycin (A) inhibits protein synthesis, Chloramphenicol (C) inhibits the peptidyl transferase activity during protein synthesis, and Imipinem (D) is a β-lactam antibiotic that inhibits bacterial cell wall synthesis. Thus, only Rifampin specifically targets bacterial RNA synthesis among the given choices.

Correct Answer: B

Rationale: Step 1: Identify the conditions - ascaridosis and enterobiosis are caused by roundworms and pinworms, respectively. Step 2: Understand mechanism - Pyrantel works by paralyzing the worms, leading to expulsion from the body. Step 3: Specificity - Pyrantel is effective against both roundworms and pinworms. Step 4: Safety - Pyrantel is considered safe for use in treating these infections. Summary: A: Bithionol - used for tapeworm infections, not effective for roundworms or pinworms. C: Praziquantel - effective against tapeworms and flukes, not roundworms or pinworms. D: Suramin - used for African sleeping sickness, not indicated for ascaridosis or enterobiosis.

Correct Answer: D

Rationale: The correct answer is D: Decreased reabsorption of Ca2+ in the loop of Henle. Furosemide is a loop diuretic that inhibits the Na+/K+/2Cl- co-transporter in the thick ascending limb of the loop of Henle, leading to decreased reabsorption of Na+ and Ca2+. This leads to an increase in the excretion of Ca2+ in the urine, resulting in metabolic alkalosis due to loss of H+ ions in exchange for Na+ and Ca2+. A: Increased reabsorption of uric acid is not directly related to furosemide-induced metabolic alkalosis. B: Increased delivery of Na+ to the distal tubule would lead to increased reabsorption of Na+ and water, which would not result in metabolic alkalosis. C: Mild inhibition of carbonic anhydrase would not directly cause furosemide-induced metabolic alkalosis.

Correct Answer: A

Rationale: The correct answer is A: Inhibition of carbonic acid dehydration in the tubular lumen. Acetazolamide inhibits the enzyme carbonic anhydrase in the proximal convoluted tubule of the kidney, leading to decreased reabsorption of bicarbonate ions and subsequent loss of bicarbonate in the urine. This results in a metabolic acidosis which can help alleviate symptoms of congestive heart failure by reducing the workload on the heart. Choice B is incorrect because acetazolamide actually leads to increased bicarbonate excretion, not reabsorption. Choice C is incorrect because acetazolamide does not directly affect Na+ reabsorption in the distal tubule. Choice D is incorrect because acetazolamide does not stimulate H+ reabsorption in the proximal tubule; rather, it inhibits carbonic acid dehydration.

Correct Answer: B

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.