In the following schematic drawing of connexons as seen from the cytosol of a cell, what is the approximate diameter of each of the pores? Which of the indicated connexons (1 or 2) is more likely to have been incorporated more recently?
A) About 20 nm; connexon 1
B) About 4 nm; connexon 1
C) About 1.5 nm; connexon 1
D) About 4 nm; connexon 2
E) About 1.5 nm; connexon 2

Question

In the following schematic drawing of connexons as seen from the cytosol of a cell, what is the approximate diameter of each of the pores? Which of the indicated connexons (1 or 2) is more likely to have been incorporated more recently? 
A) About 20 nm; connexon 1 
B) About 4 nm; connexon 1 
C) About 1.5 nm; connexon 1 
D) About 4 nm; connexon 2 
E) About 1.5 nm; connexon 2

Quizplus · Accepted Answer

The pore formed by the intercellular channels in gap junctions is about 1.5 nm in diameter, allowing the diffusion of only small molecules. Gap-junction plaques are dynamic structures; new channels are added at the periphery and older channels are removed from near the center of the plaque.

In the Following Schematic Drawing of Connexons as Seen from the Cytosol