What is the role of mRNA in protein synthesis?

DNA-mRNA-ProteinProtein synthesis is a multiple steps biological process. The living cells use mRNA molecules to create all required for their functioning protein molecules. There is a cellular  component which takes part in each of the protein synthesis steps. This vital component is called “messenger RNA” (abbreviated as mRNA). The role of mRNA in protein synthesis is to transfer the information encoded in the DNA to the cytoplasm. The ribosomes are in the the cytoplasm and there the actual protein creation happens. Thus without the presence of mRNA, the process of protein synthesis would be actually not possible.

The Role of mRNA in Protein Synthesis Is to Bring DNA Information to the Ribosomes

As you probably know, each eukaryotic cell stores it’s genetic material in the form of double stranded DNA molecules in its nucleus. These DNA molecules never leave the nucleus, because:

  • as they store huge amount of information, they are quite big
  • the nucleus pores are smaller than the average size of the DNA molecules
  • leaving the nucleus could cause damages (or at least changes) in the molecule, which could affect the stored information in the DNA

Thus the DNA molecules are virtually locked in the nucleus, where they stay in a safe environment.

On the other hand, the protein synthesis organelles of the cell, called ribosomes, reside in the cytoplasm. Ribosomes reside either as free in the cytoplasm or they bind to the outer membrane of the rough endoplasmic reticulum.

mRNA Is Responsible for the Specificity of Protein Synthesis

DNA transcriptionAnother important aspect of the protein synthesis is that each cell does not need to synthesize all of their proteins encoded in it’s DNA. Cells need particular set of proteins at the right time (and place)! Thus the involvement of the mRNA in the process of protein synthesis is very important. The transcription of the DNA information into mRNA sequence copies just a portion of the DNA genetic material, which encodes for a single protein (or a group of related protein molecules). In this  way, the cells have all the required proteins for their current needs. However they do not exhaust their protein synthesis apparatus synthesizing unneeded proteins.

Important Role of mRNA in Protein Synthesis Is to Speed up the Production of Proteins

Besides some multi-copy genes, usually a a cell has just one gene template encoded in their DNA molecules. Each cell needs thousands up to hundreds of thousands of molecules per protein  type. These molecules needs to be renewed with new ones regularly. To synthesize such huge amount of items from a single template, cells have found a clever way to parallelize the process. They use mRNA molecules to multiply the source DNA template into larger number of mRNA templates. Then the ribosomes use these mRNA templates to synthesize multiple number of the same protein in parallel. This speeds up the process of protein synthesis significantly!

So to summarize what is the role of mRNA in protein synthesis, we have to point out 3 main functions. First, the role of mRNA in protein synthesis is to transfer the encoded information in DNA to the ribosomes in the cytoplasm. Secondly, involvement of mRNA as a mediator allows the synthesis of only the required proteins in each particular moment. In addition, the DNA transcription into multiple copies of mRNA, determines the production of enough proteins molecules required for the normal cell functioning.

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