The "Central Dogma of Biology"


The idea of protein synthesis is often known as the central dogma since it the most elementary concept required to understand all of biology. All living things undergo the process of protein synthesis. The three major players in the central dogma are DNA, RNA and proteins.


The Original Blueprint - DNA

All living things require a blueprint, a recipe book, to make various essential molecules in our body namely proteins. Like most other organisms, the blueprint for humans is found in the form of DNA which we inherit from our parents. DNA is composed of four molecules known as bases: adenine, thymine, guanine and cytosine (A, T, G and C respectively). Segments of various sequences of these bases are what make up genes. Millions of such bases are found in a copy of DNA, allowing for an almost infinite number of combinations of bases to form genes.



A diagram showing DNA to RNA Transcription. The diagram is captioned "Using an enzyme known as RNA polymerase genetic information in DNA is converted, or 'transcribed', into RNA

The modified photocopy - RNA

For proteins to be made, information stored in DNA must be first converted into another form. A process known as transcription converts the gene from DNA to RNA, a very similar molecule. This is like photocopying the original blueprint (DNA) onto a different type of paper. Through evolution, the protein making machinery known as the ribosome, can only understand genetic information in the form of RNA.

Depending upon what the gene codes for, the molecules may proceed onto becoming proteins or remain as RNA. The genes that remain as RNA and don’t proceed to become proteins, serve important functions for the cell including helping other RNA molecules in becoming proteins.



RNA Translation Diagram. The Diagram Reads "The ribosome moves along the RNA, reading the genetic information. As the ribosome reads the gene, amino acids are assembled, as per the information in the gene. These amino acids bond together as the ribosome moves along the RNA strand, to eventually form a complete protein."


The Finished Product - Protein

Proteins are one of the macromolecules, which are essential building blocks of life. A protein is made up of many amino acids bonded together. They are quite abundant in the body, and serve various purposes. Enzymes acting at the molecular level, muscles that move our bodies, hair, nails and eye colour pigment are only a few examples of proteins found in the body. 
Information stored in RNA is converted to proteins by a tiny organelle known as a ribosome. This protein making machine reads the sequence of bases in the RNA. This tells the ribosome where the gene starts, stops and what amino acids are required to assemble the protein. This protein is then transported within the cell where it is required. This central dogma of biology is observed in all living things.