occupied as ribosomes move along it, synthesizing protein according
to its nucleotide sequence. Consequently, the number and spacing of
ribosomes in a polyribosome indicate the length of the mRNA molecule and hence the size of the protein being made. The two subunits
have separate roles in protein synthesis. The 40S subunit is the site of
attachment and translation of mRNA. The 60S subunit is responsible
for the release of the new protein and, where appropriate, attachment
to the endoplasmic reticulum via an intermediate docking protein that
directs the newly synthesized protein through the membrane into the
cisternal space.

###### Golgi apparatus (Golgi complex)
The Golgi apparatus is a distinct cytomembrane system located near the