Video Transcript
What is a subunit of a ribosome
made of? (A) A long rRNA folded in many
loops. (B) rRNA and many different types
of polypeptides. (C) tRNA and many different
polypeptide chains. (D) A subsection of the nucleolus
and its associated DNA. (E) mRNA, tRNA, and rRNA.
In order to answer this question,
we need to review the structure and function of ribosomes. The ribosome is an organelle that
translates mRNA into a sequence of amino acids using transfer or tRNA molecules. Ribosomes contain a large and small
subunit that sandwich the messenger RNA during translation. The large subunit is made up of
noncoding RNA called ribosomal RNA or rRNA and about 49 different polypeptides in
eukaryotes, while the smaller subunit also contains rRNA and about 33 different
polypeptides in eukaryotes.
Therefore, the correct answer is
(B), rRNA and many different types of polypeptides.
