Mineral and Trace Element Metabolism MCQs

Biochemistry · 29 free questions with answers & explanations.

1. A 30-year-old woman presents with hepatic cirrhosis, Kayser-Fleischer rings and neuropsychiatric symptoms. Serum ceruloplasmin is low. In Wilson's disease, the defective protein ATP7B normally functions to:
2. Hepcidin is the master regulator of systemic iron homeostasis. It reduces serum iron by which mechanism?
3. Selenium deficiency (Keshan disease) manifests as cardiomyopathy. Selenium is essential because it is incorporated as selenocysteine in which critical antioxidant enzyme?
4. Zinc is a cofactor for more than 300 enzymes. Acrodermatitis enteropathica is an autosomal recessive condition due to defective zinc absorption. The protein mutated is:
5. Hepcidin is the master regulator of iron homeostasis. In chronic inflammatory states (anemia of chronic disease), hepcidin levels are markedly elevated. The molecular mechanism by which elevated hepcidin causes hypoferremia is:
6. In Wilson's disease (hepatolenticular degeneration), the defective ATP7B protein fails to incorporate copper into ceruloplasmin and excrete it into bile. Kayser-Fleischer rings form due to copper deposition in which structure?
7. Zinc is an essential cofactor for carbonic anhydrase. In severe zinc deficiency (as in acrodermatitis enteropathica), reduced zinc-dependent enzyme activity would impair which physiological process?
8. Hepcidin is the master regulator of iron homeostasis. In a patient with anemia of chronic disease (ACD), the MECHANISM by which elevated hepcidin sequesters iron is:
9. Wilson's disease is a genetic disorder of copper metabolism. The defective protein ATP7B normally functions to:
10. A premature neonate develops neonatal tetany with hypocalcaemia. Lab findings: serum Ca2+ 1.4 mmol/L (low), phosphate 2.8 mmol/L (high), PTH low-normal, vitamin D normal. The MOST likely diagnosis is:
11. Zinc is a cofactor for multiple metalloenzymes. Which enzyme's activity is classically used as a FUNCTIONAL biomarker of zinc status in clinical biochemistry?
12. Hepcidin is the master regulator of systemic iron homeostasis. In the setting of anaemia of chronic disease (ACD), serum hepcidin is elevated. The mechanism by which elevated hepcidin causes iron-restricted erythropoiesis is:
13. Wilson's disease is caused by mutations in ATP7B. Excess copper accumulates causing hepatic and neurological disease. The biochemical reason kayser-Fleischer rings form in Descemet's membrane of the cornea rather than elsewhere is:
14. Zinc deficiency causes acrodermatitis enteropathica, alopecia, impaired wound healing, and immune dysfunction. The molecular explanation for zinc's role in immune function involves:
15. FGF23 (fibroblast growth factor 23) is produced by osteocytes in response to hyperphosphataemia and elevated vitamin D. The primary renal action of FGF23 (acting via FGFR1-Klotho receptor complex) is:
16. Hepcidin is the master regulator of systemic iron homeostasis. In chronic inflammation (e.g., rheumatoid arthritis), elevated hepcidin causes anemia of chronic disease. The MOLECULAR mechanism of hepcidin action is:
17. Wilson's disease (hepatolenticular degeneration) is caused by ATP7B mutation. The biochemical consequence of ATP7B dysfunction that explains both the hepatic and neurological manifestations is:
18. FGF23 is a phosphatonin secreted by osteocytes in response to elevated phosphate. In X-linked hypophosphatemia (XLH), PHEX gene mutations cause elevated FGF23. The mechanism by which elevated FGF23 causes hypophosphatemia is:
19. A patient with acrodermatitis enteropathica has a mutation in SLC39A4 (ZIP4), a zinc transporter. Zinc deficiency impairs wound healing primarily because zinc is a cofactor for:
20. Hereditary haemochromatosis (HFE-associated) results in excessive dietary iron absorption. The molecular mechanism involves defective HFE protein failing to upregulate which hepatic hormone that normally reduces ferroportin-mediated iron export from enterocytes and macrophages?
21. Wilson's disease results from impaired copper excretion due to ATP7B mutation. In which organelle does ATP7B normally incorporate copper into ceruloplasmin and direct excess copper into bile?
22. A 6-month-old exclusively breastfed infant presents with acrodermatitis enteropathica — vesiculobullous rash around orifices, alopecia, and diarrhoea. The defect impairs absorption of which mineral via a ZIP4 transporter?
23. Calcitriol (1,25-dihydroxyvitamin D) promotes intestinal calcium absorption by inducing synthesis of which calcium-binding protein in enterocytes?
24. Selenium is an essential trace element incorporated as selenocysteine (the 21st amino acid) into selenoproteins. Which clinically important selenoprotein protects thyroid hormone from excess oxidation during synthesis?
25. Hepcidin, the master regulator of iron homeostasis, causes iron deficiency anaemia of chronic disease by:
26. Wilson's disease results from mutation in ATP7B (copper-transporting ATPase) and manifests with all of the following EXCEPT:
27. Zinc deficiency classically presents with all of the following EXCEPT:
28. A patient with chronic kidney disease has hyperphosphataemia, hypocalcaemia, and elevated PTH. The elevated PTH in this setting is most directly driven by:
29. Selenium is an essential trace element required as selenocysteine in which important antioxidant enzyme?