What does 'S' refer in a 70S and 80S ribosome?

Explanation

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the meaning of 'S' in the context of ribosomes, specifically in the terms 70S and 80S.

2. **Identifying the 'S'**: The 'S' in 70S and 80S refers to the sedimentation coefficient, which is a measure of how fast a particle sediments when subjected to centrifugal force.

3. **Origin of the Term**: The 'S' stands for the Svedberg unit, named after the Swedish chemist Theodor Svedberg, who developed the method of ultracentrifugation.

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