Haem Synthesis, Porphyrias and Bile Pigments
- Previous year questions on Haem Synthesis, Porphyrias and Bile Pigments for NEET PG (National Eligibility cum Entrance Test - Postgraduate), from the Biochemistry section of the exam.
- Most questions here come from previous-year papers of Indian postgraduate medical entrance and licensing exams; where a paper and year are recorded the question carries them. The image-based questions are original vignettes written around an openly licensed figure, and were never asked in any exam.
- 25 live questions in Haem Synthesis, Porphyrias and Bile Pigments.
- 1 of 25 questions carries a verified exam year: 2019.
- Biochemistry is worth about 16 of 300 questions on the exam. See every subject’s weightage.
- Question set last updated 6 Sept 2026.
Q1.The four pyrole rings in hemoglobin molecule are joined together by?
- ADisulphide bridges
- BMethylene bridges✓ Correct answer
- CHydrogen bonds
- DAlpha bonds
Q2.Which of the following is not true about Porphyria cutanea tarda (PCT)
- AIs the least common type of human porphyria✓ Correct answer
- BDecreased activity of the enzyme uroporphyrinogen decarboxylase
- CPrior hepatitis C virus infection appears to be an independent risk factor.
- DTreatment of PCT consists of repeated phlebotomies.
Q3.All of the following types of porphyria are autosomal dominant Except
- AAcute intermittent porphyria
- BPorphyria cutanea tarda
- CCongenital erythropoetic porphyria✓ Correct answer
- DHereditary coproporphyria
Q4.Conversion of uroporphyrinogen III to coproporphyrinogen III is an example of
- ADeamination
- BDecarboxylation✓ Correct answer
- CHydrogenation
- DDehydrogenation
Q5.In Heme synthesis, which of the following is inhibited by LEAD?
- AXanthine oxidase
- BALA dehydratase✓ Correct answer
- CALA synthase
- DUroporphyrin synthase
Q6.A 16-year-old girl presented with abdominal pain after administration of a sulfa drug. She was incoherent and suffered a seizure. Which of the following is the most likely possibility?
- AAcute intermittent porphyria✓ Correct answer
- BCongenital erythropoietic porphyria
- CAdenosine deaminase deficiency
- DHGPRTase deficiency
Q7.Which TCA intermediate is used in haem synthesis:
- AFumarate
- BAlpha keto gluterate
- CMalate
- DSuccinyl CoA✓ Correct answer
Q8.intermediate of kreb cycle used in heme synthesis;
- Asuccinyl-CoA✓ Correct answer
- BAlpha ketoglutarate
- CCitrate
- DAspartate
Q9.In lead poisoning, there is an inhibition of some of the enzymes of the heme biosynthetic pathway. This is reflected by the accumulation of what substance in blood?
- AUroporphyrinogen III
- BFerrochelatase
- CPorphobilinogen
- DDelta amino levulinic acid✓ Correct answer
Q10.A girl complaints of acute abdominal pain on and off with tingling sensation of limbs. She had a history of eating paint from the wall of newly built house. Which of the following enzyme deficiency will be the cause of her condition?
- AALA dehydratase✓ Correct answer
- BALA synthase
- CCoproporphyrinogen synthase
- DHeme synthase
Answer key
Q1: B. Methylene bridges; Q2: A. Is the least common type of human porphyria; Q3: C. Congenital erythropoetic porphyria; Q4: B. Decarboxylation; Q5: B. ALA dehydratase; Q6: A. Acute intermittent porphyria; Q7: D. Succinyl CoA; Q8: A. succinyl-CoA; Q9: D. Delta amino levulinic acid; Q10: A. ALA dehydratase.
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