Why does 30 s and 50s together join to form 80 s ribosome and not 70 s ?
Answers
Answered by
0
Because ribisome do the work of protein synthesis
30s+50s=80s
30s+50s=80s
Answered by
2
As others wrote, “s” is the Svedberg coefficient and is a measure of the rate of sendimentation under the influence of density gredient sedimentation.
Now, what happens when you sendiment something? In the Centrifuge machine, during centrifugation, two forces act downward on the sedimenting sample. One is centrifugal force and another one is gravity.
Now apply a little high school physics. Every action has it's equal and opposite reaction. So, there's also an upward pull generated during centrifugation, which pushes the sample up from the beneath. And a sample sediments in it's corresponding zone while simultaneously three forces act upon it from two opposite directions.
Now, what happens when you sediment prokaryotic ribosomal subunits together and individually when these three forces act upon them ?
When you sediment the large subunit, downward push acts on its upper surface while upward pull acts on its lower surface. And it shows a 50s sedimentation.
Similarly, in case of the small subunit sedimentation, both forces act and accordingly it shows a 30s sedimentation.
Now, when you sediment the whole ribosome, you can relate the fact that there is no space in between the two subunits. They are attached together. And so, during sedimentation, only two open surfaces (the upper surface of one subunit and the lower surface of the other subunit) are available to be acted upon by the forces and not the total 4.
So the sedimentation rate of the entire ribosome is not the total sum of that of the individual subunits. It is always less due to the unavailability of two open surfaces.
So it is not 50s + 30s = 80s. In stead, it is 50s + 30s = 70s .
Now you can also figure out the case of sedimentation of eukaryotic ribosome ( Why is it 60s + 40s = 80s )
Now, what happens when you sendiment something? In the Centrifuge machine, during centrifugation, two forces act downward on the sedimenting sample. One is centrifugal force and another one is gravity.
Now apply a little high school physics. Every action has it's equal and opposite reaction. So, there's also an upward pull generated during centrifugation, which pushes the sample up from the beneath. And a sample sediments in it's corresponding zone while simultaneously three forces act upon it from two opposite directions.
Now, what happens when you sediment prokaryotic ribosomal subunits together and individually when these three forces act upon them ?
When you sediment the large subunit, downward push acts on its upper surface while upward pull acts on its lower surface. And it shows a 50s sedimentation.
Similarly, in case of the small subunit sedimentation, both forces act and accordingly it shows a 30s sedimentation.
Now, when you sediment the whole ribosome, you can relate the fact that there is no space in between the two subunits. They are attached together. And so, during sedimentation, only two open surfaces (the upper surface of one subunit and the lower surface of the other subunit) are available to be acted upon by the forces and not the total 4.
So the sedimentation rate of the entire ribosome is not the total sum of that of the individual subunits. It is always less due to the unavailability of two open surfaces.
So it is not 50s + 30s = 80s. In stead, it is 50s + 30s = 70s .
Now you can also figure out the case of sedimentation of eukaryotic ribosome ( Why is it 60s + 40s = 80s )
Similar questions