Let us look at mammalian systems as a example to help us understand this question.
Transcription involves the synthesis of RNA from a DNA template. It occurs in the nucleus of cells since that is where the DNA resides. On the other hand, protein synthesis (or translation) occurs in the cytoplasm of cells. Translation involves the synthesis of protein from RNA.
There are three main types of RNA that are transcribed from DNA. The first is messenger RNA ...
This solutions explains why not all transcribed genes are translated into proteins.