Final answer:
Larger molecules like proteins and nucleic acids cannot pass through gap junctions, which are channels formed by connexins that allow small molecules and ions to transfer between adjacent animal cells.
Step-by-step explanation:
The type of cell constituent that does not pass through a gap junction is larger molecules such as proteins and nucleic acids. Gap junctions are specialized structures in animal cells that allow for the transport of water, ions, and small molecules between adjacent cells.
They are made up of proteins called connexins that arrange into a connexon, forming a channel for communication and enabling vital functions such as the synchronized contraction of heart muscle cells through the efficient transmission of electrical signals. In contrast to gap junctions, structures like plasmodesmata in plant cells serve a similar communication role but differ structurally.