Question

Which of the following makes it necessary for animal cells, although they have no cell walls, to have intercellular junctions?

A) Cell membranes do not distinguish the types of ions and molecules passing through them.
B) Large molecules, such as proteins and RNA molecules, do not readily get through one, much less two, adjacent cell membranes.
C) Cell-to-cell communication requires physical attachment of one cell to another.
D) Maintenance of tissue integrity and barriers to fluid leakage requires cells to adhere tightly to one another.
E) The relative shapelessness of animal cells requires a mechanism for keeping the cells aligned.

Answer 1

Interacellular junctions in animal cells, like tight junctions, desmosomes, and gap junctions, serve to maintain tissue integrity, prevent fluid leakage, and facilitate cell-to-cell communication.

Step-by-step explanation:

Interacellular junctions are crucial in animal cells for several reasons, despite the absence of cell walls. Intercellular junctions like tight junctions, desmosomes, and gap junctions facilitate various functions and maintain the structural integrity of tissues in multicellular organisms. Tight junctions form watertight seals preventing material leakage, desmosomes mechanically attach cells providing tissue strength, and gap junctions allow the transfer of ions and small molecules for cell communication. Among the options provided, the most correct answer is D) Maintenance of tissue integrity and barriers to fluid leakage requires cells to adhere tightly to one another. This is because tight junctions form barrierrs that prevent materials from leaking between the cells and are found in tissues lining internal organs and cavities.