Prokaryotic Ribosomes and Polysomes — NEET Biology
📚 Practice ConceptIn prokaryotes, ribosomes are associated with the plasma membrane of the cell. They are about 15 nm by 20 nm in size and are made of two subunits - 50S and 30S units which when present together form 70S prokaryotic ribosomes. Ribosomes are the site of protein synthesis. Several ribosomes may attach to a single mRNA and form a chain called polyribosomes or polysome. The ribosomes of a polysome translate the mRNA into proteins.
Why are ribosomes in prokaryotes called 70S even though their subunits are 50S and 30S?
View solution & NCERT explanation
Correct answer: C — Because S stands for sedimentation coefficient and it's non-additive
Svedberg units are not additive; they depend on size, shape, and density.
What does NCERT say about prokaryotes ribosomes are associated?
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