INI-CET 2026 - Biochemistry Practice Questions

Q: A newborn presents with craniofacial abnormalities, severely reduced muscle tone, and seizures. Biochemical analysis reveals elevated very long chain fatty acids in serum. What is the most likely underlying cause?

Peroxisomal biogenesis defect. ***Peroxisomal biogenesis defect*** - The classic presentation of **Zellweger syndrome**, a peroxisomal biogenesis disorder, includes craniofacial abnormalities (e.g., high forehead, large anterior fontanelle), profound hypotonia, and seizures in the neonatal period. - This condition is caused by mutations in **PEX genes**, leading to the absence of functional peroxisomes and the subsequent **accumulation of very long chain fatty acids (VLCFAs)** in the serum. *Mitochondrial inheritance* - Mitochondrial disorders typically present with symptoms such as lactic acidosis, myopathy, or encephalopathy, but they do not specifically cause the elevation of VLCFAs. - Inherited via **maternal lineage**, these defects usually involve defects in the electron transport chain rather than fatty acid oxidation pathways. *Lysosomal storage disorder* - These disorders are characterized by the accumulation of substrates due to deficient enzymes within lysosomes, as seen in conditions like Gaucher or Tay-Sachs disease. - They generally present with progressive organomegaly (e.g., hepatosplenomegaly) and neurodegeneration rather than the characteristic craniofacial dysmorphism and VLCFA elevation seen in peroxisomal defects. *Simultaneously activate multiple tumor suppressor genes* - This is not a mechanism related to metabolic storage diseases or peroxisomal function. - Tumor suppressor gene activation is a concept associated with cancer genetics and abnormal cell growth, not metabolic enzyme deficiencies.

Question 1

A newborn presents with craniofacial abnormalities, severely reduced muscle tone, and
seizures. Biochemical analysis reveals elevated very long chain fatty acids in serum. What is the
most likely underlying cause?

Accepted Answer

Peroxisomal biogenesis defect

Answer

Mitochondrial inheritance

Answer

Lysosomal storage disorder

Answer

Simultaneously activate multiple tumor suppressor genes

Question 2

A laboratory worker accidentally inhales fumes of an oxidative phosphorylation uncoupling
agent. Which of the following physiological changes is most likely to occur?

Accepted Answer

increased O2 consumption, increased Body temperature, decreased ATP production

Answer

decreased O2 consumption, increased Body temperature, increased ATP production

Answer

increased O2 consumption, decreased Body temperature, increased ATP production

Answer

decreased O2 consumption, decreased Body temperature, decreased ATP production

INI-CET 2026 — Biochemistry