Question

For each protein, identify its targeting pathway: the sequence of cellular locations in which the protein is found from when translation is complete until it reaches its final (functional) destination. (Note that if an organelle is listed in a pathway, the location implied is inside the organelle, not in the membrane that surrounds the organelle.) View Available Hint(s)

Answer 1

Answer:

PFK (protein): cytoplasm only (targeting pathway)

Insulin (protein): ER->Golgi->outside cell

Explanation:

Translation is often referred to as the mechanism that leads to the formation of protein via the mRNA.

If a certain protein is to act within the same cell, it won't require any kind of modification enabling it's easy transport to the exterior of the cell. Such forms of proteins are translated on free cytoplasmic ribosomes and are transported directly into the cytoplasm to enable it undertake it's duties. Such as, PFK protein.

If a protein needs to act on the exterior of the cell where it is formed, then it needs to undergo modification. This kind of proteins are translated through the rough ER followed by its modification in the Golgi complex and then moved to the exterior of the cell to the region where it needs to act. As in the case of insulin.

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Let's add the missing piece of information for more clarity on the question.

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.

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.

For each protein, identify its targeting pathway: the sequence of cellular locations in which the protein is found from when translation is complete until it reaches its final (functional) destination. (Note that if an organelle is listed in a pathway, the location implied is inside the organelle, not in the membrane that surrounds the organelle.)

a. Cytoplasm only, ER --> cytoplasm, ER --> Golgi --> outside cell, cytoplasm --> ER --> outside cell, Golgi --> ER --> outside cell, cytoplasm --> Golgi --> outside cell, nucleus --> cytoplasm, ER --> Golgi --> cytoplasm

b. Protein Targeting Pathway

c. PFK _______________

d. Insulin _______________