Question

Which of the following sequences represent a possible pathway in the production of a secretory protein?

• A. Rough ER $\to$ Secretory vesicle $\to$ Ribosome $\to$ Golgi apparatus
• B. Ribosome $\to$ Rough ER $\to$ Golgi apparatus $\to$ Secretory vesicle
• C. Secretory vesicle $\to$ Golgi apparatus $\to$ Ribosomes $\to$ Rough ER
• D. Rough ER $\to$ Ribosomes $\to$ Secretory vesicles $\to$ Golgi apparatus

Answer 1

Answer: (D)

Rough ER $\to$ Ribosomes $\to$ Secretory vesicles $\to$ Golgi apparatus

• The mRNA is produced in the nucleus and then transported out in the cytoplasm.
• The mRNA is translated to form the proteins in the endoplasmic reticulum (ER).
• The rough endoplasmic reticulum contains the ribosomes on the surface. These ribosomes help in the translation of the mRNA.
• The proteins which are formed are packaged in the secretory vesicles.
• These secretory vesicles help in the transport of the proteins to the Golgi apparatus.
• The proteins move from the cis- to medial- and then to trans-Golgi. The proteins are then transported to their destination with the help of transport vesicles.
• The proteins are folded during the process from the nucleus to the ER to Golgi.

Thus, the correct answer is option D.