The DNA in a cell's nucleus encodes proteins that are eventually targeted to every membrane and compartment in the cell, as well
as proteins that are targeted for secretion from the cell. For example, consider these two proteins:
1. Phosphofructokinase (PFK) is an enzyme that functions in the cytoplasm during
glycolysis.
2. Insulin, a protein that regulates blood sugar levels, is secreted from specialized
pancreatic cells.
The question is incomplete. The part of the question after this is: Assume that you can track the cellular locations of these two proteins from the time that translation is complete until the proteins reach their final destinations.
Answer:
PFK: cytoplasm
insulin: ER--> Golgi--> outside cell
Explanation:
The proteins which are made and have to function in the same cell like Phosphofructokinase (PFK) do not have to undergo the modification processes which are required fro transporting a protein. Such kind of proteins are translated in the free cytoplasmic ribosomes and released into the cytoplasm where they start to function.
The proteins like insulin need to be traveled to different cells where they have to function. Such kind of proteins are formed in the ribosomes which have rough Endoplasmic Reticulum attached to them. From here, they travel to the Golgi complex where they are modified and packaged. From the Golgi-complex, these proteins are moved out of the cell.
