Question

Imagine a protein that functions in the ER but requires modification in the Golgi apparatus before achieving that function. Describe the protein's path through the cell, starting with the mRNA molecule that specifies the protein.

Short answer

The mRNA produced from the DNA travels to the cytoplasm, where the ribosome converts these mRNA into proteins. These proteins are transferred to the Golgi apparatus for packaging. The Golgi, in turn, returns the protein to the ER for protein functioning.

Step-by-step solution

Definition of mRNA

mRNA is the messenger RNA that is produced from DNA. The processes through which mRNA is produced are known as transcription. The messenger RNA is the single-stranded molecule that contains the codes for producing the protein.

Structure of the ER and Golgi apparatus

The membranous organelle that is found attached to the nucleus is the endoplasmic reticulum. Ribosomes are found attached to the membrane of ER. The organelle that has stacked pouches and appears like a flattened structure is the Golgi complex.

Fate of protein in ER and Golgi apparatus    

The proteins are produced from the mRNA by the process of translationthat occurs in the ribosome located in the endoplasmic reticulum. Ribosomes are tiny particles that act as a site of protein synthesis.

The protein produced from the endoplasmic lumen travels to the Golgi complex and gets packed in it. After reaching the Golgi complex, the proteins are ready to be dispatched to the targeted organelle or function.

So, the protein functioning in the ER will travel from the Golgi bodies to the ER.