Chart the path of molecules of a secreted protein beginning at the DNA for a eukaryote.

Nucleus :

Holds DNA and all the components of proteins.

All Eukaryotic cells have a nucleus and the rest of the membrane-bound organelles

Prokaryotic cells have no nucleus

Ribosomes :

Take the amino acids and package them into protein chains.

Ribosomes are on the outside of the endoplasmic reticulum

Endoplasmic Reticulum :

Organelle that transports the completed protein within the cell

Golgi Apparatus

Transports the completed protein from the ER to the outside of the cell.  Vesicles carrying the proteins break off the Golgi apparatus moving the proteins outside of the cell

Plasma Membrane

Selectively permeable membrane that allows passage of many materials into and out of the cell.

Transport proteins on the surface help send out messenger proteins to other cells.

Explanation:

Once proteins leave the cell they will be received by another cell.  In this way, cells are able to communicate with each other.  All cells have protein receptors on them which recognize specific proteins.