The central dogma of molecular biology explains how genetic information flows inside a living cell.
It describes the process by which the information stored in DNA is used to make proteins, which carry out most of the cell’s functions.
The central dogma can be summarized in three main steps:
- Replication – DNA makes an exact copy of itself.
- This ensures that genetic information is passed from cell to cell during division.
- Transcription – The information in DNA is copied into messenger RNA (mRNA).
- The enzyme RNA polymerase reads the DNA and makes a strand of RNA.
- Translation – The mRNA is used as a template to build a protein.
- Ribosomes read the mRNA code and join amino acids together in the correct sequence to form a protein.
In simple form, the central dogma is:
DNA → RNA → Protein
This means that information flows from DNA to RNA, and then from RNA to protein, but not usually in the reverse direction.
However, in some viruses (like retroviruses), RNA can be converted back into DNA using an enzyme called reverse transcriptase. This is an exception to the usual flow of information.
In short, the central dogma explains how genes control the structure and function of cells by determining which proteins are made.