Question

The nicotinic acetylcholine receptors are transmembrane protein found in the plasma membrane of human neurons. You are studying a member of the receptor family that is glycosylated. Based on this information, answer the following questions:

Was the receptor synthesized on cytosolic ribosomes or ER-bound ribosomes? Justify your answer

Describe the cellular path that the receptor likely took from synthesis to the plasma membrane.

Answer 1

ER bound ribosomes - The glycosylated nicotonic acetylcholine receptors are those which are glycosylated by addition of a glycosyl molecule. This is basically attached to the hydroxyl group and hence helps in enzyme directed reaction in the body. The glycosylation reaction is something that takes place in the endoplasmic reticulum and hence it takes place on the ribosome that is present on the ER.

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As the protein or receptor started its synthesis process in the ER, the production of the polypeptide starts on the ribosome that is bound to the ER. Once the receptor is formed, it is glycosylated with a glycosyl molecule which acts as signal for its next process which is transport to the Golgi apparatus in form of vesicle. When it reaches the Golgi apparatus, it is further processed and packaged so that it becomes ready for the transport into the plasma membrane. Once the complete packaging is done, it is transferred with help of vesicles into the plasma membrane where it is fused.