<img src="https://d5nxst8fruw4z.cloudfront.net/atrk.gif?account=iA1Pi1a8Dy00ym" style="display:none" height="1" width="1" alt="" />
Skip Navigation

Protein Synthesis

Molecular events required to generate a polypeptide from a DNA sequence in eukaryotes.

Atoms Practice
Estimated3 minsto complete
Practice Protein Synthesis
This indicates how strong in your memory this concept is
Estimated3 minsto complete
Practice Now
Turn In
Protein Synthesis

Photograph of an assembly line

Credit: Image copyright Mikheyev Viktor, 2014
Source: http://www.shutterstock.com
License: CC BY-NC 3.0

What an organized process!

The assembly line is an American invention that was developed around 1901 to mass-produce cars. Prior to that time, teams of workers would build a car together. With the advent of the assembly line, cars could be produced much more quickly and at lower cost. The assembly line idea quickly spread to other products, like the light bulbs shown above. Being able to line up parts in order and have a smooth process for putting those parts together means that an item can be produced quickly and reproducibly, coming out the same way every time.

Protein Synthesis

The process of protein synthesis is summarized in the diagram below. DNA produces an RNA template which then directs the amino acids to be introduced into the growing protein chain in the proper sequence. A specific transfer-RNA (tRNA) attaches to each specific amino acid and brings the amino acid to the RNA for incorporation.

Overview of protein synthesis

Credit: Courtesy of the National Institutes of Health
Source: http://commons.wikimedia.org/wiki/File:MRNA-interaction.png
License: CC BY-NC 3.0

Overview of protein synthesis[Figure2]

The first step in the process is transcription - the unfolding of DNA and the production of a messenger-RNA (mRNA) strand. This step takes place in the nucleus of the cell.

Overview of transcription

Credit: User:Calibuon/En.Wikibooks
Source: http://commons.wikimedia.org/wiki/File:Transcription.jpg
License: CC BY-NC 3.0

Formation of RNA from DNA[Figure3]

The DNA uncoils and provides the pattern for the formation of a single strand of mRNA. After production of the RNA, the DNA refolds into the original double helix. The mRNA is exported to the cytoplasm (outside the nucleus) for further processing.

Amino acids will link with specific tRNA molecules for proper placement in the protein chain. The tRNA is a small coiled molecule that accepts an amino acid on one end and matches up to a specific three-base portion of the mRNA on the other end. The tRNA interacts with the mRNA so as to put the amino acid in the proper sequence for the developing protein. After adding the amino acid to the sequence, the tRNA is then cleaved from the amino acid and recycled for further use in the process.

The process of amino acid assembly takes place in the ribosome. This structure consists of two subunits containing ribosomal RNA that enclose the mRNA and catalyze the formation of the amide linkages in the growing protein in a process known as translation. When protein synthesis is complete, the two subunits dissociate and release the completed protein chain. 

The process of protein synthesis is fairly fast. Amino acids are added to the growing peptide chain at a rate of about 3-5 amino acids per second. A small protein (100-200 amino acids) can be produced in a minute or less.

Overview of translation

Credit: Mariana Ruiz Villarreal (Wikimedia: LadyofHats)
Source: http://commons.wikimedia.org/wiki/File:TRNA_ribosomes_diagram_en.svg
License: CC BY-NC 3.0

Role of ribosome in protein synthesis[Figure4]


  1. What is transcription?
  2. What is translation?
  3. What molecule gets the amino acid in the sequence at the proper time?

Notes/Highlights Having trouble? Report an issue.

Color Highlighted Text Notes
Please to create your own Highlights / Notes
Show More

Image Attributions

  1. [1]^ Credit: Image copyright Mikheyev Viktor, 2014; Source: http://www.shutterstock.com; License: CC BY-NC 3.0
  2. [2]^ Credit: Courtesy of the National Institutes of Health; Source: http://commons.wikimedia.org/wiki/File:MRNA-interaction.png; License: CC BY-NC 3.0
  3. [3]^ Credit: User:Calibuon/En.Wikibooks; Source: http://commons.wikimedia.org/wiki/File:Transcription.jpg; License: CC BY-NC 3.0
  4. [4]^ Credit: Mariana Ruiz Villarreal (Wikimedia: LadyofHats); Source: http://commons.wikimedia.org/wiki/File:TRNA_ribosomes_diagram_en.svg; License: CC BY-NC 3.0

Explore More

Sign in to explore more, including practice questions and solutions for Protein Synthesis.
Please wait...
Please wait...