BioCoach Activity

Concept 8: Molecular Components of Translation 2

Ribosomes

Ribosomes, the organelles on which the mRNA is translated, consist of two subunits, each of which contains rRNA and ribosomal proteins.

In translation, the mRNA passes through the ribosome, where the codons are recognized by tRNAs carrying the specified amino acids.

Each ribosomal subunit consists of rRNA (ribosomal RNA, encoded by rRNA genes) and ribosomal proteins.

In eukaryotes, the large subunit is 60S (named for how fast it sediments during centrifugation) and contains 28S, 5.8S, and 5S rRNAs plus about 50 ribosomal proteins. The small subunit is 40S and contains 18S rRNA plus about 30 proteins.