Question

Gap junctions are formed by?

1) groups of 8-12 connexons making a pore in one cell.
2) groups of 4-6 innexins or connexins forming a pore in one cell.
3) connexons from adjacent cells connecting with each other to form a cytoplasmic bridge.
4) both A and C
5) both B and C

Answer 1

Gap junctions are formed by the alignment of connexons, complexes of six connexin proteins, across adjacent cell membranes, creating a direct channel for substance exchange, essential for synchronized cell functions. The correct answer is option 5.

Step-by-step explanation:

Gap junctions are specialized intercellular connections between a multitude of animal cell-types. They are formed when connexons, which are complexes of protein channels, meet at the intercellular space. Each connexon is made up of six protein subunits called connexins, which are arranged in a ring or an elongated donut-like configuration to form a pore within one plasma membrane.

When the pores of connexons from adjacent cells align, they create a continuous channel that allows for the direct passage of ions, water, and small molecules. This is essential for numerous physiological processes, such as the synchronized contraction of cardiac muscle cells.

Therefore, the correct answer to the question on how gap junctions are formed is 3) connexons from adjacent cells connecting with each other to form a cytoplasmic bridge. Hence, 5) both B and C is the correct option in the final answer.