image
Figure 2–70. Cheme, elucidating the common features and differences in mitochondria and chloroplast structures.
image
Figure 2–71. Chloroplast of Chrysanthemum segetum in course of division (After Lance, 1958; From Kirk and Tilney-Bassett, 1967).
Ribosomes
They are small spheric formations (Fig. 2–72), extremely uniform in shape,
structure and chemical composition. Their dimensions vary from 15 to 35 nm.
They are observed in all kinds of cells — prokaryotic and eukaryotic. The
ribosomes are freely located in cytoplasm or attached to the outer
membranes of some organelles — mitochondria, chloroplasts, endoplasmatic
reticulum, etc.