Final answer:
In prokaryotes, the large ribosomal subunit is 50S, the small is 30S, and together they form a 70S ribosome. Svedberg (S) units are used to measure these subunits, reflecting their sedimentation rates during ultracentrifugation rather than their actual masses.
Step-by-step explanation:
The value of the large ribosomal subunit in a prokaryote, measured in Svedberg (S) units, is 50S. The value of the small ribosomal subunit is 30S. When combined, they form a 70S ribosome, which is typical for prokaryotes. The measurement in Svedberg units reflects how ribosomal subunits move during ultracentrifugation, which is related to their size and shape, rather than mass directly. Since Svedberg units are not additive, when the 50S and 30S subunits combine, they do not equate to 80S but rather result in the complete 70S prokaryotic ribosome.