Heredity is the passing of characteristics/traits of parents to their offspring.On the other hand, variation is the process of the changes occurring, or the differences of the inherited characteristics/traits. 

The process converting the information in a sequence of nitrogenousbases in mRNA into a sequence of amino acids that make a protein isknown as translation. While transcription is the process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA)