Protein Synthesis
- Cell Biology

If you have jumped straight to this page, you may wish to look at the previous page about DNA, which gives background information on protein synthesis.

As mentioned, a string of nucleotides represent the genetic information that makes us unique and the blueprint of who and what we are, and how we operate. Part of this genetic information is devoted to the synthesis of proteins, which are essential to our body and used in a variety of ways. Proteins are created from templates of information in our DNA, illustrated below:

An example nucleotide sequence containing a template for protein synthesis

The X marked nucleotides are an example of a DNA sequence that would be used to code for a particular protein, with the sequence of these nucleotides determining which protein it is.

The sequence of these nucleotides are used to create amino acids, where chains of amino acids form to make a protein.


This genetic information is found in the nucleus, though protein synthesis actually occurs in ribosomes found in the cytoplasm and on rough endoplasmic reticulum. If protein is to be synthesised, then the genetic information in the nucleus must be transferred to these ribosomes. This is done by mRNA (messenger ribonucleic acid). It is very similar to DNA, but fundamentally differs in two ways

  • A base called uracil replaces all thymine bases in mRNA.
  • The deoxyribose sugar in DNA in is replaced by ribose sugar in mRNA.

At the beginning of protein synthesis, just like DNA replication, the double helix structure of DNA uncoils in order for mRNA to replicate the genetic sequence responsible for the coding of a particular protein.

In the beginning, the DNA has uncoiled, allowing the mRNA to move in and transcribe (copy) the genetic information. If the code of DNA looks like this : G-G-C-A-T-T, then the mRNA would look like this C-C-G-U-A-A (remembering that uracil replaces thymine)

With the genetic information responsible for creating substances now available on the mRNA strand, the mRNA moves out of the nucleus and away from the DNA towards the ribosomes.

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