Question

For each enzyme, state the kind of ribosome on which it’s made (cytosolic or RER). If it’s made on a RER ribosome, state the final destination of the protein in the endomembrane system:

- Glucose Na+ symporter
- Actin, which polymerizes into actin filaments, aka microfilaments
- A mature acid hydrolase that will function as an intracellular peptidase

Thank you!

Answer 1

A) Glucose Na+ symporter is synthesized in ribosomes on rough endoplasmic reticulum because it is an membrane protein. It is processed, packed and transported via golgi vesicles to merge it with plasma membrane. The function includes transport of Glucose or sodium ion either into or out of the cell.

B) Actin is a cytoskeleton protein and therefore it is synthesized in the ribosomes of cytosol. It's destination is cytosol itself as it forms the cytoskeleton along with myosin protein. The function includes transport of molecules to various destinations and in cell division to pull chromosomes apart.

C) Acid hydrolase as intracellular peptidase is synthesized in the ribosomes on rough endoplasmic reticulum because it is a lysosomal protein. Once synthesized, it is processed, packed and transported to lysosome by vesicles. The function includes digestion of peptides or proteins which is mal functioned.