RIBOSOMES

Transport processes are based on the movement of matter when a force is exerted upon them (1). Diffusion, centrifugation, and electrophoresis are all based on forces causing moveme

nt or flow of particles. Diffusion is the migration of particles based on a concentration gradient. Sedimentation and electrophoresis are two transport processed in which the force exerted serves to separate particles. Sedimentation depends upon an increase in centrifugal force to cause a flow of matter. Electrophoresis is performed with an electrical field to provide the force necessary to cause the migration of particles through a medium. The purpose of this study is to use the transport processes of sedimentation and electrophoresis to isolate and examine certain components of prokaryotic and eukaryotic ribosomes. Using differential centrifugation, 70S E.coli Mre 600 ribosomes and 80S wheat germ ribosomes will be isolated. A protein extract from these ribosomes will be obtained by acetic acid/acetone precipitation and analyzed by a SDS-PAGE (Sodium dodecylsulfate polyacrylamide gel). A CHCl3 extraction method will be employed to isolate the RNA components of the ribosomes, which will be analyzed on an agarose gel. Standards will be used in both gels, and results will be compared to literature data. Differential centrifugation works upon the principle that the force on various molecules in a centrifugal field differs depending on mass. Fc, the centrifugal force on a molecule, will equal w2rm(1-vp)where r is the radius, m is the mass, w is the angular velocity of the centrifuge, and (1-vp) is the specific density of the molecule. This force differs between molecules due to varying masses of molecules. There is also a frictional force on the particle that depends on mass. The Svedberg constant is defined as m(1-vp)/f, a sedimentation constant which varies between molecules.