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Question 521
Biochemistry → General
Classification
Question
SSBAQuestion Header
Which pairing correctly matches the site of ribosomal protein synthesis with the destination of the resulting protein?
Question Stem
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Options
A
Free ribosome — lysosomal protein
B
Rough endoplasmic reticulum-bound ribosome — mitochondrial protein
C
Free ribosome — cell-membrane protein
D
Rough endoplasmic reticulum-bound ribosome — lysosomal protein
E
Rough endoplasmic reticulum-bound ribosome — peroxisomal protein
Explanation
Ribosomes attached to rough endoplasmic reticulum synthesise proteins including lysosomal, membrane, enzymatic and hormonal proteins. Free ribosomes synthesise proteins including those destined for mitochondria and peroxisomes.
Option Validity
A) Lysosomal proteins are synthesised by ribosomes attached to rough endoplasmic reticulum.
B) Mitochondrial proteins are among those synthesised by free ribosomes.
C) Cell-membrane proteins are synthesised by ribosomes attached to rough endoplasmic reticulum.
E) Peroxisomal proteins are among those synthesised by free ribosomes.
Further Reading
Richa Saxena. Textbook for MRCOG-1: Basic Sciences in Obstetrics & Gynaecology. Biochemistry and Nutrition — Biochemistry — Ribosomes. Printed page 127.