Assertion: membrane's molecule | /r/CreatedBy | one cell
Facets:
Source sentences:
text: an extracellular signaling molecule is produced by one cell and is at least capable of traveling to neighboring cells.
text: It takes molecules produced by the cell, such as proteins and lipids, modifies them if necessary (such as folding for proteins), and packs them into vesicles so that they can be shipped around or outside of the cell.