Next, the two plastid-dividing rings, or PD rings form. The inner plastid-dividing ring is located in the inner side of the chloroplast's inner membrane, and is formed first. The outer plastid-dividing ring is found wrapped around the outer chloroplast membrane. It consists of filaments about 5 nanometers across, arranged in rows 6.4 nanometers apart, and shrinks to squeeze the chloroplast. This is when chloroplast constriction begins.
In a few species like Cyanidioschyzon merolæ, chloroplasts have a third plastid-dividing ring located in the chloroplast's intermembrane space.
How far apart are the outer PD ring's filaments?
6.4 nanometers 6.4 nanometers 6.4 nanometers
It consists of filaments about 5 nanometers across, arranged in rows 6.4 nanometers apart, and shrinks to squeeze the chloroplast.
It consists of filaments about five nanometers across, arranged in rows six point four nanometers apart, and shrinks to squeeze the chloroplast.
How far apart are the outer PD ring's filaments?