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Question 565
Biochemistry → General
Classification
Question
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An unidentified membrane-bound vesicle is shown to originate from the endoplasmic reticulum rather than the Golgi apparatus. It participates in oxygen utilisation and degradation of purines to uric acid. Which additional function would support the same identification?
Question Stem
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Options
A
Formation of ribosomal subunits
B
Packaging lysosomal enzymes into primary lysosomes
C
Breakdown of excess fatty acids
D
Chromosome movement during mitosis
E
Processing proteins received at the cis face
Explanation
The organelle is a peroxisome. Peroxisomes are described as membrane-bound vesicles pinched off from the endoplasmic reticulum rather than the Golgi apparatus. Their functions include fatty-acid breakdown by beta-oxidation, detoxification of hydrogen peroxide, oxygen utilisation, acceleration of gluconeogenesis from fats, degradation of purines to uric acid, and roles in myelin and bile-acid formation.
Option Validity
A) Formation of ribosomal subunits is a nuclear function.
B) Lysosomal enzymes are processed and packed by the Golgi apparatus into vesicles that become primary lysosomes.
D) Chromosome movement during cell division is associated with centrioles.
E) Processing proteins entering at the cis face is a Golgi function.
Further Reading
Saxena R. Textbook for MRCOG-1: Basic Sciences in Obstetrics & Gynaecology. Chapter 4 — Peroxisomes. Printed page 126.