Page 18 - The Cell and Its Components

Protein Synthesis
The main job of the ribosome is to make proteins for the
cell. There can be hundreds of proteins that need to be
made for the cell, so the ribosome needs specific
instructions on how to make each protein. These
instructions come from the nucleus in the form of
messenger RNA. Messenger RNA contain specific codes
that act like a recipe to tell the ribosome how to make the
protein.

There are two main steps in making proteins:
transcription and translation. The ribosome does the
translation step. You can go here to learn more
about proteins.

Translation
Translation is the process of taking the instructions from
the messenger RNA and turning it into a protein. Here
are the steps the ribosome takes to make the protein:

 The two subunits join together with the messenger
RNA.
 The ribosome finds the correct starter place on the
RNA called the codon.
 The ribosome moves down the RNA, reading the
instructions on what amino acids to attach to the
protein. Every three letters on the RNA represents
a new amino acid.
 The ribosome attaches amino acids building up
the protein.
 It stops building the protein when it reaches a
"stop" code in the RNA telling it that the protein is
ready.