AAMC FL Practice Exam

What structural feature do desmosomes provide between tissue cells?

1. Cell signaling

2. Strong intercellular junctions

3. Cellular energy transfer

4. Diffusion barriers

The correct answer is: Strong intercellular junctions

Desmosomes are specialized structures that provide strong intercellular junctions between tissue cells, particularly in tissues that experience significant mechanical stress, such as cardiac muscle and epithelial tissues. They consist of proteins that anchor to a plaque on the inside of the plasma membrane, linked to intermediate filaments of the cytoskeleton. This architecture allows desmosomes to create a resilient connection that maintains the structural integrity of tissues, helping to resist tension and shear forces. While cell signaling can occur at various types of junctions, it is not the primary function of desmosomes. Similarly, cellular energy transfer is typically associated with other structures like mitochondria and not related to desmosome function. Diffusion barriers, while important in other contexts such as tight junctions, do not describe the strength and anchoring role that desmosomes fulfill in maintaining tissue cohesion. Therefore, the primary role of desmosomes in providing strong intercellular junctions is what makes this the correct answer.