Which of the following statements concerning vitamin B1 functions are true:

Correct Answer: B

Rationale: The correct answer is B because vitamin B1, also known as thiamine, is indeed an essential coenzyme for the oxidative decarboxylation of alpha-keto acids, including the conversion of pyruvate to acetyl coenzyme A in the citric acid cycle. This process is crucial for energy production in the form of ATP. Choice A is incorrect because vitamin B1 is not primarily an antioxidant but rather a coenzyme involved in energy metabolism. Choice C is incorrect because vitamin B1 is not required for the synthesis of prothrombin or clotting factors. Choice D is incorrect because flavoproteins, FMN, and FAD are associated with vitamin B2 (riboflavin), not vitamin B1.

Correct Answer: D

Rationale: Rationale: A: True. Calcitonin is indeed secreted by parafollicular cells of the thyroid and consists of 32 amino acids. B: True. Calcitonin lowers serum calcium and phosphate levels by acting on bones and kidneys. C: True. Calcitonin inhibits osteoclastic bone resorption, thereby protecting bone density. Therefore, the correct answer is D, as all statements are accurate and collectively describe the functions and characteristics of calcitonin.

Correct Answer: A

Rationale: The correct answer is A: 350-400 mg. The recommended daily allowance of magnesium for adults is typically around 350-400 mg. This amount is based on the average dietary intake needed to maintain optimal health and bodily functions. Magnesium plays a crucial role in various physiological processes such as muscle and nerve function, blood sugar regulation, and bone health. Choice B (6-9 g) is too high for daily magnesium intake and could lead to toxicity symptoms. Choice C (25 g) is also excessively high and can cause serious health issues. Choice D (1.5-4 mg) is too low and would not meet the body's daily magnesium requirements. Therefore, the correct answer is A as it falls within the recommended range for daily magnesium intake to support overall well-being.

Correct Answer: A

Rationale: The correct answer is A: Furosemide (Lasix). Furosemide is a loop diuretic that competitively blocks chloride channels in the ascending loop of Henle, preventing the reabsorption of sodium, potassium, and chloride in the renal tubules. This mechanism leads to increased excretion of these ions and water, resulting in diuresis. Acetazolamide (B) inhibits carbonic anhydrase, Triamterene (C) blocks sodium channels, and Mannitol (D) is an osmotic diuretic. Therefore, these choices do not competitively block chloride channels like Furosemide does in the renal tubular cells.

Correct Answer: C

Rationale: The correct answer is C: Myconazol. Myconazol is not an antibiotic; it is an antifungal drug that belongs to the class of azole antifungals. Antibiotics target bacteria, while antifungal drugs target fungi. Amphotericin B, Nystatin, and Griseofulvin are antifungal drugs that are also considered antibiotics because they inhibit the growth of fungi by various mechanisms. Amphotericin B disrupts fungal cell membrane function, Nystatin binds to ergosterol in fungal cell membranes, and Griseofulvin interferes with fungal cell division. Therefore, Myconazol is the correct answer as it does not belong to the antibiotic class.