Question

Gap junctions are formed by integral membrane protein complexes called ________, which has a channel allowing molecules smaller than ________ kD to pass through?

Answer 1

Gap junctions are formed by connexins and allow the passage of molecules smaller than 1 kD, facilitating critical intercellular communication.

Step-by-step explanation:

Gap junctions are formed by integral membrane protein complexes called connexins, which has a channel allowing molecules smaller than 1,000 daltons (approximately 1 kD) to pass through. These channels are important for cell-to-cell communication and are especially crucial in cardiac muscle where they allow for the efficient transmission of the electrical signal necessary for the heart muscle cells to contract in tandem. Each gap junction channel is formed by the alignment of two connexons, one from each adjacent cell, creating a direct passage for the diffusion of ions and small molecules.