Answer:
Rough Endoplasmic reticulum
Step-by-step explanation:
Present in all eukaryotic cells, the Endoplasmic Reticulum is the largest organelle, formed by a network of closed, interconnected, closed tubules and vesicles that form a unique internal space, called the endoplasmic reticulum lumen or cisternal space. There are two types of wndoplasmic reticulum, smooth and rough.
The rough endoplasmic reticulum has ribosomes associated with its membrane. The ribosomes that are associated with RE are in the form of polyribosomes, that is, membrane-bound by a messenger RNA (mRNA) molecule. These ribosomes are responsible for the production of proteins to be used by the RE itself and to be transported to the Golgi, to form the lysosomes or to be secreted by the cell.
It is within the rough endoplasmic reticulum that proteins form their secondary structure.
We can therefore conclude that as messenger RNA is translated by the ribosome, the growing polypeptide chain is inserted into the membrane of the rough endoplasmic reticulum before being sent to its final destination.