So the Svetberg unit usually refers to how quickly something sediments or travels along or down a test tube that is basically rotating with some angular velocity. And the Svedberg unit is directly related to the mass of our particle and it also depends on the size and the shape of the molecule. So heavier molecules will be found farther down the test tube than lighter molecules. So we see that the larger subunits the will be found farther down our test tube than the because the are basically heavier molecules. Now, what exactly is the purpose of these small and large subunits? Well, basically before our translation actually takes place, the small and large subunits are separated.