Question

Protein synthesis in an animal cell occurs :

• A. only on the ribosomes present in cytosol
• B. on ribosomes present in cytoplasm as well as in mitochondria
• C. only on ribosomes attached to the nuclear envelope and endoplasmic reticulum
• D. on ribosomes present in the nucleolus as well as in cytoplasm

Answer 1

Answer: (B)

on ribosomes present in cytoplasm as well as in mitochondria

Answer 2

Ribosomes are sturdy cellular structures found in the cytoplasm, consisting of ribosomal RNA (rRNA) and a specific group of proteins. They can be either freely floating in the cytosol or attached to the surface of the endoplasmic reticulum (ER). The choice of their location depends on the presence of an ER-targeting signal sequence on the protein being synthesized. Consequently, a given ribosome may be bound to the ER while it synthesizes one protein and reside freely in the cytosol when translating another protein.

So, the correct option is (B): on ribosomes present in cytoplasm as well as in mitochondria