A ribosome is a molecular machine that coordinates protein assembly. Ribosomes are composed of several proteins with tightly coiled RNA (called ribosomal RNA or rRNA) wrapped around them. Ribosomes consist of two parts, the large and small subunits, which clamp around the mRNA that needs to be translated.A ribosome brings together correctly the mRNA, which needs to be translated, and the tRNA, which assists in the translation process, to come together correctly. During translation, tRNA molecules carrying amino acids are positioned in the ribosome’s two docking sites. Afterwards, this machinery can disassemble and be reused many times. In the upcoming animation, you will see a ribosome assembling a polypeptide chain, a future protein.