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Question 562
Biochemistry → General
Classification
Question
SSBAQuestion Header
Which pair of proteins would both be expected to originate from rough-ER-bound ribosomes?
Question Stem
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Options
A
Mitochondrial and peroxisomal proteins
B
Haemoglobin and mitochondrial proteins
C
Peroxisomal and lysosomal proteins
D
Lysosomal and cell-membrane proteins
E
Haemoglobin and peroxisomal proteins
Explanation
Rough-ER-bound ribosomes synthesise enzymatic proteins, hormonal proteins, lysosomal proteins and cell-membrane proteins. Free cytoplasmic ribosomes synthesise proteins associated with haemoglobin, peroxisomes and mitochondria.
Option Validity
A) Both mitochondrial and peroxisomal proteins are assigned to free ribosomes.
B) Both haemoglobin-associated and mitochondrial proteins are assigned to free ribosomes.
C) Lysosomal proteins are associated with rough-ER-bound ribosomes, but peroxisomal proteins with free ribosomes.
E) Both are assigned to free cytoplasmic ribosomes.
Further Reading
Saxena R. Textbook for MRCOG-1: Basic Sciences in Obstetrics & Gynaecology. Chapter 4 — Ribosomes. Printed page 127.