Color enhanced transmission electron microscope (TEM) of a field of monomeric ribosomes. The ribosome is a complex molecular machine, found within all living cells, that serves as the site of biological protein synthesis (translation). Amino acids are natural monomers that polymerize at ribosomes to form proteins. Shown here are several frontal (arrows) and lateral (double arrows) images. Most lateral images are of the "right" type and most frontal images are left-featured, but one is right-featured (marked by a circle). An image which is intermediate between a right-featured frontal and left lateral image is also seen (circle with double arrows). Small subunit partitions are indicated by short arrows. Note that in left-featured frontal images the dense line in between subunits is not prominent towards the right side of the dense spot which is under the small subunit partition. Magnification 225,000x @ 5x7 inches.