Question

Is there any reason as to why Ribosomes are found attached to Endoplasmic Reticulum

Answer 1

Ribosomes are not exactly attached to ER. During protein synthesis ER just provides a surface to which ribosomes can adhere to. On the other occasions the ribosomal subunits i.e. 60s and 40s subunits are free in the cytoplasm.When a mRNA is transcribed then the ribosomes assemble themselves. Also the proteins synthesized by these ribosomes are generally transfered to the ER lumen and then sort of exported outside the cell. While the proteins translated by free cytoplasmic ribosomes are used inside the cell.
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