Ribosomes are non-membrane bound organelles and they play a vital role in protein synthesis. Thus, the statement that ribosomes have no role in protein synthesis is incorrect.
Other statements are true for ribosome
Ribosomes are made up of two subunits, i.e., large and small.
In prokaryotes it is 70S ( 50S and 30S ).
In eukaryotes it is 80S ( 60S and 40S ).
Polyribosomes
Several ribosomes attach to a single mRNA , and form a chain like structure.
Polysomes
They are formed by the attachment of ribosomes with mRNA.

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