Answer to Question #42936 in Microbiology for Rafique alam mengal

Question

Q; Why two subunits of prokaryotic ribosomes 50s plus 30s equal to 70s why not 80s? pleas give me answer in detail.

Answer 1

Ribosomal subunits are identified by their S (Svedberg unit) values,sedimentation coefficients that refer to their rate of sedimentation in a centrifuge. The S values are not necessarily additive when subunits are combined, because rates of sedimentation are affected by shape and surface area as well as mass. Total surface area of ribosome is less than arithmetic sum of the areas of the subunits.