Ribosome

 A ribosome is the particle upon which mRNA from DNA transcription is translated to a polypeptide with a specific amino acid sequence defined by the genetic code. It is comprised of 2 subunits:

30S unit: This is the smaller unit which can be divided into 21 proteins and a 16S RNA molecule

50S unit: This is the larger unit which can be divided into 34 proteins and 2 RNA molecules, 23S and 5S

The 2 units together form the complete ribosome, known as the 70S unit. S refers to the Svedberg unit, which is a measure of rate at which a compound moves when centrifuged.

As ribosomes contain RNA (also referred to as ribosomal RNA-rRNA) and protiens, they are also referred to as ribonucleoproteins.