Question

Prokaryotic ribosomes are _______.

• A. $50S$
• B. $60S$
• C. $70S$
• D. $80S$

Answer 1

Answer: (C)

$70S$

All prokaryotes have $70S$ (where S=Svedberg units) ribosomes while eukaryotes contain larger $80S$ ribosomes in their cytosol. The $70S$ ribosome is made up of a $50S$ and $30S$ subunits. The $50S$ subunit contains the $23S$ and $5S$ rRNA while the $30S$ subunit contains the $16S$ rRNA.

So the correct answer is option C.