���˿���

Every cell in a multicellular organism contains a complete set of chromosomes with every gene needed to make every protein that that organism will ever make.

However, in any particular cell, only a very small fraction of these genes are ever expressed.

Each cell is specialised to carry out a certain task and will only need to express certain genes.

Gene expression is the process by which specific genes are activated to produce a required protein. An organism's phenotype is determined by the proteins produced, depending on environmental factors.

The gene expression process is made up of the transcription and translation of DNA sequences. This involves RNA.