Question

The Acetylcholine receptor is embedded in the cell membrane of the dendrite. Neurotransmitters like dopamine and serotonin are proteins that need to be secreted. Which means both AchR and neurotransmitters are processed through the endomembrane system by being inserted into the ER during translation.

DONT describe signal hypothesis !

Explain differences in the process of insertion in the ER that is found between the AchR and a Neurotransmitter. INCLUDE specific amino acid sequences that differ between the two protein types and their location in the ER after translation is complete.

Answer 1

• These  receptors are composed of five transmembrane polypeptides.
• The signal is released from a nerve terminal at a neuromuscular junction.
• This receptor is present at skeletal muscles where specialized chemical synapse occurs in between motor neuron and a skeletal muscle cell.  

The neurotransmitter is a chemical signal which will be received by a particular receptor.

So the receptor and neurotransmitter are two distinct things.

Acetylcholine itself is a neurotransmitter it is synthesized from acetyl coenzyme A and choline by an enzyme choline acetyltransferase.

• Endomembrane system is nothing but a complete pathway of protein synthesis.
• In which from nucleus to target organelle occurs.
• In this system, protein is synthesized, packed and transported to its place of function.
• So this case is also applied in case of the Acetylcholine receptor because it is a protein.
• But neurotransmitter is not a protein so it is not part of the endomembrane system.
• There is a difference in both but not in case of insertion as their nature is different one is a receptor and another one is a chemical signal.     
• Location of AchR is a skeletal muscle cell and the signal can reach there in the form of neurotransmitter which is transmitted by neurons.